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{{redirect|Morphia|other uses|Morphia (disambiguation)|and|Morphine (disambiguation)}}
GOD'S DIVINE ESSENCE OF PERFECTNESS STRAIGHT FROM HEAVEN.{{Analgesics}}
{{distinguish|Morphinae|Morphea|Morpholine}}
{{Use dmy dates|date=June 2015}}
{{Drugbox
| Watchedfields = same
| verifiedrevid = 477170110
| drug_name =
| IUPAC_name = (4R,4aR,7S,7aR,12bS)-3-methyl-2,3,4,4a,7,7a-hexahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinoline-7,9-diol
| image = Morphin - Morphine.svg
| image2 = Morphine-from-xtal-3D-balls.png

<!--Clinical data-->
| pronounce = {{IPAc-en|ˈ|m|ɔr|f|iː|n}}
| tradename = MScontin, Oramorph, Sevredol, and others<ref name="drugs.com-page" />
| Drugs.com = {{drugs.com|monograph|morphine-sulfate}}
| pregnancy_AU = C
| pregnancy_US = C
| legal_AU = S8
| legal_CA = Schedule I
| legal_DE = Anlage III
| legal_NZ = Class B
| legal_US = Schedule II
| legal_UK = Class A
| legal_UN = N I III
| legal_status =
| dependency_liability = Physical: High<br />Psychological: Moderate-High
| addiction_liability = High
| routes_of_administration = [[Inhalation]] ([[smoking]]), [[Insufflation (medicine)|insufflation]] (snorting), [[oral administration|oral]] (PO), [[rectal]], [[Subcutaneous injection|subcutaneous]] (SC), [[intramuscular]] (IM), [[intravenous]] (IV), [[epidural]], and [[intrathecal]] (IT)

<!--Pharmacokinetic data-->
| bioavailability = 20–40% (oral), 36–71% (rectally),<ref name="pmid3387374">{{cite journal |vauthors=Jonsson T, Christensen CB, Jordening H, Frølund C | title = The bioavailability of rectally administered morphine | journal = Pharmacol. Toxicol. | volume = 62 | issue = 4 | pages = 203–5 |date=April 1988 | pmid = 3387374 | doi = 10.1111/j.1600-0773.1988.tb01872.x }}</ref> 100% (IV/IM)
| protein_bound = 30–40%
| metabolism = [[Hepatic]] 90%
| onset = 5 min (IV), 15 min (IM),<ref>{{cite book|last1=Whimster|first1=Fiona|title=Cambridge textbook of accident and emergency medicine|date=1997|publisher=Cambridge University Press|location=Cambridge|isbn=978-0-521-43379-2|page=191|url=https://books.google.ca/books?id=m0bNaDhkaukC&pg=PA191}}</ref> 20 min (PO)<ref>{{cite book|last1=Liben|first1=Stephen|title=Oxford textbook of palliative care for children|date=2012|publisher=Oxford University Press|location=Oxford|isbn=978-0-19-959510-5|page=240|edition=2|url=https://books.google.ca/books?id=k3XNeNseoHIC&pg=PA240}}</ref>
| elimination_half-life = 2–3 h
| duration_of_action = 3 to 7 hours<ref name=AHFS2015 /><ref name=Rockwood2009 />
| excretion = Renal 90%, biliary 10%

<!--Identifiers-->
| CAS_number_Ref = {{cascite|correct|??}}
| CAS_number = 57-27-2
| CAS_supplemental = <br />64-31-3 (neutral sulfate),<br />52-26-6 (hydrochloride)
| ATC_prefix = N02
| ATC_suffix = AA01
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 17303
| PubChem = 5288826
| IUPHAR_ligand = 1627
| DrugBank_Ref = {{drugbankcite|correct|drugbank}}
| DrugBank = DB00295
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 4450907
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 76I7G6D29C
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = D08233
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 70

<!--Chemical data-->
| C=17 | H=19 | N=1 | O=3
| molecular_weight = 285.34 g/mol
| smiles = CN1CC[C@]23C4=C5C=CC(O)=C4O[C@H]2[C@@H](O)C=C[C@H]3[C@H]1C5
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C17H19NO3/c1-18-7-6-17-10-3-5-13(20)16(17)21-15-12(19)4-2-9(14(15)17)8-11(10)18/h2-5,10-11,13,16,19-20H,6-8H2,1H3/t10-,11+,13-,16-,17-/m0/s1
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = BQJCRHHNABKAKU-KBQPJGBKSA-N
| solubility = HCl & sulf.: 60
}}

<!-- Definition and uses -->
'''Morphine''', sold under many [[trade names]],<ref name="drugs.com-page" /> is a [[analgesic|pain medication]] of the [[opiate]] type.<!-- <ref name=AHFS2015 /> --> It acts directly on the [[central nervous system]] (CNS) to decrease the feeling of pain.<!-- <ref name=AHFS2015 /> --> It can be used for both [[acute pain]] and [[chronic pain]].<!-- <ref name=AHFS2015 /> --> Morphine is also frequently used for pain from [[myocardial infarction]] and during [[Childbirth|labour]].<!-- <ref name=AHFS2015 /> --> It can be given by mouth, by [[intramuscular|injection into a muscle]], by [[Subcutaneous injection|injecting under the skin]], [[intravenously]], into the space around the [[spinal cord]], or [[rectal administration|rectally]].<ref name=AHFS2015 /> Maximum effect is around 20 min when given intravenously and 60 min when given by mouth while duration of effect is between three and seven hours.<ref name=AHFS2015 /><ref name=Rockwood2009>{{cite book|last1=Rockwood|first1=Charles A.|title=Rockwood and Wilkins' fractures in children.|date=2009|publisher=Lippincott Williams & Wilkins|location=Philadelphia, Pa.|isbn=978-1-58255-784-7|page=54|edition=7th|url=https://books.google.ca/books?id=QVIdXV_F8M4C&pg=PA54}}</ref> Long-acting formulations also exist.<ref name=AHFS2015>{{cite web|title=Morphine sulfate|url=http://www.drugs.com/monograph/morphine-sulfate.html|publisher=The American Society of Health-System Pharmacists|accessdate=1 June 2015}}</ref>

<!-- Side effects -->
Potentially serious [[side effects]] include a decreased respiratory effort and [[hypotension|low blood pressure]].<!-- <ref name=AHFS2015 /> --> Morphine has a high potential for [[addiction]] and [[substance abuse|abuse]].<!-- <ref name=AHFS2015 /> --> If the dose is reduced after long-term use, [[opioid withdrawal|withdrawal]] may occur.<!-- <ref name=AHFS2015 /> --> Common side effects include drowsiness, vomiting, and constipation.<!-- <ref name=AHFS2015 /> --> Caution is advised when used during [[pregnancy]] or [[breast feeding]], as morphine will affect the infant.<ref name=AHFS2015 />

<!-- History -->
Morphine was first isolated between 1803 and 1805 by [[Friedrich Sertürner]].<ref name=Court2009>{{cite book|last1=Courtwright|first1=David T.|title=Forces of habit drugs and the making of the modern world|date=2009|publisher=Harvard University Press|location=Cambridge, Mass.|isbn=978-0-674-02990-3|pages=36–37|edition=1|url=https://books.google.ca/books?id=GHqV3elHYvMC&pg=PA36}}</ref> This is generally believed to be the first isolation of an [[active ingredient]] from a plant.<ref name=Luch2009>{{cite book | url = https://books.google.com/?id=MtOiLVWBn8cC&pg=PA20 | page = 20 | title = Molecular, clinical and environmental toxicology | editor = Luch A | publisher = Springer | year = 2009 | isbn = 3-7643-8335-6 }}</ref> [[Merck KGaA|Merck]] began marketing it commercially in 1827.<ref name=Court2009 /> Morphine was more widely used after the invention of the [[hypodermic syringe]] in 1853–1855.<ref name=Court2009 /><ref name=Clay2013 /> Sertürner originally named the substance ''morphium'' after the Greek god of dreams, [[Morpheus (mythology)|Morpheus]], for its tendency to cause sleep.<ref name=Clay2013>{{cite book|author1=Clayton J. Mosher|title=Drugs and Drug Policy: The Control of Consciousness Alteration|date=2013|publisher=SAGE Publications|isbn=978-1-4833-2188-2|page=123|url=https://books.google.ca/books?id=2UQXBAAAQBAJ&pg=PA123}}</ref><ref>{{cite book|last1=Fisher|first1=Gary L.|title=Encyclopedia of substance abuse prevention, treatment, & recovery|date=2009|publisher=SAGE|location=Los Angeles|isbn=978-1-4522-6601-5|page=564|url=https://books.google.ca/books?id=DFR2AwAAQBAJ&pg=PT598}}</ref>

<!-- Society and culture -->
The primary source of morphine is isolation from [[poppy straw]] of the [[opium poppy]].<ref>{{cite book|title=Narcotic Drugs Estimated World Requirements for 2008, Statistics for 2006.|date=2008|publisher=United Nations Pubns|location=New York|isbn=9789210481199|page=77|url=https://books.google.ca/books?id=0_9QHvacPzYC&pg=PA77}}</ref> In 2013, an estimated 523,000 kilograms of morphine were produced.<ref name=UN2015 /> About 45,000 kilograms were used directly for pain, an increase over the last twenty years of four times.<ref name=UN2015 /> Most use for this purpose was in the [[developed world]].<ref name=UN2015>{{cite book|title=Narcotic Drugs 2014|date=2015|publisher=INTERNATIONAL NARCOTICS CONTROL BOARD|isbn=9789210481571|pages=21, 30|url=https://www.incb.org/documents/Narcotic-Drugs/Technical-Publications/2014/Narcotic_Drugs_Report_2014.pdf|format=pdf}}</ref> About 70% of morphine is used to make other opioids such as [[hydromorphone]], [[oxycodone]] and [[heroin]].<ref name=UN2015 /><ref name=Trig2006>{{cite book|last1=Triggle|first1=David J.|title=Morphine|date=2006|publisher=Chelsea House Publishers|location=New York|isbn=978-1-4381-0211-5|pages=20–21|url=https://books.google.ca/books?id=sud4ORAMNkYC&pg=PA20}}</ref><ref name=Kar2006>{{cite book|last1=Karch|first1=Steven B.|title=Drug abuse handbook|date=2006|publisher=CRC/Taylor & Francis|location=Boca Raton|isbn=978-1-4200-0346-8|pages=7–8|edition=2nd|url=https://books.google.ca/books?id=F0mUte90ATUC&pg=PA7}}</ref> It is a Schedule II drug in the [[United States]],<ref name=Trig2006 /> Class A in the [[United Kingdom]],<ref>{{cite book|last1=Macpherson|first1=edited by Gordon|title=Black's medical dictionary|date=2002|publisher=A & C Black|location=London|isbn=978-0-7136-5442-4|page=162|edition=40th|url=https://books.google.ca/books?id=bUnCAwAAQBAJ&pg=PA162}}</ref> and Schedule I in [[Canada]].<ref>{{cite book|title=Davis's Canadian Drug Guide for Nurses|date=2014|publisher=F.A. Davis|isbn=978-0-8036-4086-3|page=1409|url=https://books.google.ca/books?id=0Y8QBAAAQBAJ&pg=PA1409}}</ref> It is on the [[WHO Model List of Essential Medicines]], the most important medications needed in a basic [[health system]].<ref>{{cite web|title=WHO Model List of Essential Medicines|format=PDF|url=http://apps.who.int/iris/bitstream/10665/93142/1/EML_18_eng.pdf?ua=1|work=World Health Organization|accessdate=22 April 2014|date=October 2013}}</ref>
{{TOC limit|3}}

== Medical uses ==

=== Pain ===
Morphine is used primarily to treat both acute and chronic severe [[pain]]. It is also used for pain due to [[myocardial infarction]] and for labor pains.<ref name=AHFS>{{cite web | title=Morphine Sulfate | url = http://www.drugs.com/monograph/morphine-sulfate.html | publisher = The American Society of Health-System Pharmacists | accessdate = 3 April 2011}}</ref> Its duration of analgesia is about three to seven hours.<ref name=AHFS2015 /><ref name=Rockwood2009 />

However, concerns exist that morphine may increase mortality in the setting of [[non ST elevation myocardial infarction]].<ref name="pmid15976786">{{cite journal |vauthors=Meine TJ, Roe MT, Chen AY, Patel MR, Washam JB, Ohman EM, Peacock WF, Pollack CV, Gibler WB, Peterson ED | title = Association of intravenous morphine use and outcomes in acute coronary syndromes: results from the CRUSADE Quality Improvement Initiative | journal = Am. Heart J. | volume = 149 | issue = 6 | pages = 1043–9 |date=June 2005 | pmid = 15976786 | doi = 10.1016/j.ahj.2005.02.010 }}</ref> Morphine has also traditionally been used in the treatment of [[acute pulmonary edema]].<ref name=AHFS /> A 2006 review, though, found little evidence to support this practice.<ref>{{cite web | url = http://www.bestbets.org/bets/bet.php?id=376 | title = BestBets: Does the application of opiates, during an attack of Acute Cardiogenic Pulmonary Oedma, reduce patients' mortality and morbidity? | author = Sosnowski MA | work = BestBets | publisher = Best Evidence Topics | accessdate = 6 December 2008 }}</ref> A 2016 Cochrane review concluded that morphine is effective in relieving cancer pain. Side-effects of nausea and constipation are rarely severe enough to warrant stopping treatment.<ref>{{cite journal|last1=Wiffen|first1=Philip J|last2=Wee|first2=Bee|last3=Moore|first3=R Andrew|title=Oral morphine for cancer pain|journal=Cochrane Database of Systematic Reviews|date=22 April 2016|volume=4|doi=10.1002/14651858.cd003868.pub4|url=http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD003868.pub4/full|accessdate=26 April 2016|publisher=John Wiley & Sons, Ltd|language=en}}</ref>

=== Shortness of breath ===
Immediate-release morphine is beneficial in reducing the symptom of [[shortness of breath]] due to both [[cancer]] and noncancer causes.<ref name=Pal2010>{{cite journal |vauthors=Schrijvers D, van Fraeyenhove F |title=Emergencies in palliative care |journal=Cancer J |volume=16 |issue=5 |pages=514–20 |year=2010 |pmid=20890149 |doi=10.1097/PPO.0b013e3181f28a8d }}</ref><ref>{{cite journal |vauthors=Naqvi F, Cervo F, Fields S |title=Evidence-based review of interventions to improve palliation of pain, dyspnea, depression |journal=Geriatrics |volume=64 |issue=8 |pages=8–10, 12–4 |date=August 2009 |pmid=20722311 |doi= }}</ref> In the setting of breathlessness at rest or on minimal exertion from conditions such as advanced cancer or end-stage cardiorespiratory diseases, regular, low-dose sustained-release morphine significantly reduces breathlessness safely, with its benefits maintained over time.<ref name="pmid22336677">{{cite journal |vauthors=Parshall MB, Schwartzstein RM, Adams L, Banzett RB, Manning HL, Bourbeau J, Calverley PM, Gift AG, Harver A, Lareau SC, Mahler DA, Meek PM, O'Donnell DE | title = An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea | journal = Am. J. Respir. Crit. Care Med. | volume = 185 | issue = 4 | pages = 435–52 |date=February 2012 | pmid = 22336677 | doi = 10.1164/rccm.201111-2042ST }}</ref><ref name="pmid20202949">{{cite journal |vauthors=Mahler DA, Selecky PA, Harrod CG, Benditt JO, Carrieri-Kohlman V, Curtis JR, Manning HL, Mularski RA, Varkey B, Campbell M, Carter ER, Chiong JR, Ely EW, Hansen-Flaschen J, O'Donnell DE, Waller A | title = American College of Chest Physicians consensus statement on the management of dyspnea in patients with advanced lung or heart disease | journal = Chest | volume = 137 | issue = 3 | pages = 674–91 |date=March 2010 | pmid = 20202949 | doi = 10.1378/chest.09-1543 }}</ref>

=== Opioid use disorder ===
Morphine is also available as a slow-release formulation for [[opiate substitution therapy]] (OST) in Austria, Bulgaria, and Slovenia, for addicts who cannot tolerate either methadone or [[buprenorphine]].<ref name="NEPOD Report">{{cite book | url = http://www.health.gov.au/internet/drugstrategy/publishing.nsf/Content/8BA50209EE22B9C6CA2575B40013539D/$File/mono52.pdf+ | title = National Evaluation of Pharmacotherapies for Opioid Dependence (NEPOD): Report of Results and Recommendation |author1=Mattick RP |author2=Digiusto E |author3=Doran C |author4=O’Brien S |author5=Kimber J |author6=Henderson N |author7=Breen B |author8=Shearer J |author9=Gates J |author10=Shakeshaft A |author11=NEPOD Trial Investigators | year = 2004 | format = PDF | work = Monograph Series No. 52 | publisher = Australian Government | isbn = 0-642-82459-2 }}</ref>

== Contraindications ==
Relative [[contraindication]]s to morphine include:
* [[Hypoventilation|respiratory depression]] when appropriate equipment is not available<ref name=AHFS2015 />
* Although it has previously been thought that morphine was contraindicated in [[acute pancreatitis]], a review of the literature shows no evidence for this.<ref name="pmid11316181">{{cite journal | author = Thompson DR | title = Narcotic analgesic effects on the sphincter of Oddi: a review of the data and therapeutic implications in treating pancreatitis | journal = Am. J. Gastroenterol. | volume = 96 | issue = 4 | pages = 1266–72 |date=April 2001 | pmid = 11316181 | doi = 10.1111/j.1572-0241.2001.03536.x }}</ref>

== Adverse effects ==
{{quote box
|title=Adverse effects of opioids
|
;Common and short term
* [[Itch]]<ref name="Furlan">{{cite journal |vauthors=Furlan AD, Sandoval JA, Mailis-Gagnon A, Tunks E | title = Opioids for chronic noncancer pain: A meta-analysis of effectiveness and side effects | journal = Canadian Medical Association Journal | volume = 174 | issue = 11 | pages = 1589–1594 | year = 2006 | pmid = 16717269 | pmc = 1459894 | doi = 10.1503/cmaj.051528 }}</ref>
* [[Nausea]]<ref name="Furlan" />
* [[Vomiting]]<ref name="Furlan" />
* [[Constipation]]<ref name="Furlan" />
* [[Somnolence|Drowsiness]]<ref name="Furlan" />
* [[Xerostomia|dry mouth]]<ref name="Furlan" />
;Other
* [[Opioid dependence]]
* [[Dizziness]]
* Decreased sex drive
* impaired sexual function
* Decreased testosterone levels
* [[Depression (mood)|Depression]]
* [[Immunodeficiency]]
* [[Opioid-induced hyperalgesia|opioid-induced abnormal pain sensitivity]]
* [[Irregular menstruation]]
* Increased risk of [[Falling (accident)|falls]]
* Slowed breathing
}}
[[File:MorphineRx.JPG|thumb|A localized reaction to intravenous morphine caused by histamine release in the veins]]

=== Constipation ===
Like [[loperamide]] and other opioids, morphine acts on the [[myenteric plexus]] in the intestinal tract, reducing gut motility, causing constipation. The gastrointestinal effects of morphine are mediated primarily by [[mu Opioid receptor|μ-opioid receptors]] in the bowel. By inhibiting gastric emptying and reducing propulsive [[peristalsis]] of the intestine, morphine decreases the rate of intestinal transit. Reduction in gut secretion and increased intestinal fluid absorption also contribute to the constipating effect. Opioids also may act on the gut indirectly through tonic gut spasms after inhibition of [[nitric oxide]] generation.<ref name="pmid15082884">{{cite journal |vauthors=Stefano GB, Zhu W, Cadet P, Bilfinger TV, Mantione K | title = Morphine enhances nitric oxide release in the mammalian gastrointestinal tract via the micro(3) opiate receptor subtype: a hormonal role for endogenous morphine | journal = J. Physiol. Pharmacol. | volume = 55 | issue = 1 Pt 2 | pages = 279–88 |date=March 2004 | pmid = 15082884 | doi = }}</ref> This effect was shown in animals when a nitric oxide precursor, [[L-arginine]], reversed morphine-induced changes in gut motility.<ref name="Calignano, Moncada and Di Rosa">{{cite journal |vauthors=Calignano A, Moncada S, Di Rosa M | title = Endogenous nitric oxide modulates morphine-induced constipation | journal = Biochem. Biophys. Res. Commun. | volume = 181 | issue = 2 | pages = 889–93 |date=December 1991 | pmid = 1755865 | doi = 10.1016/0006-291X(91)91274-G }}</ref>

=== Hormone imbalance ===
{{See also|Opioid#Hormone_imbalance}}
Clinical studies consistently conclude that morphine, like other opioids, often causes [[hypogonadism]] and [[hormone imbalance]]s in chronic users of both sexes. This side effect is [[dose–response relationship|dose-dependent]] and occurs in both therapeutic and recreational users. Morphine can interfere with menstruation in women by suppressing levels of [[luteinizing hormone]]. Many studies suggest the majority (perhaps as much as 90%) of chronic opioid users have opioid-induced hypogonadism. This effect may cause the increased likelihood of [[osteoporosis]] and [[bone fracture]] observed in chronic morphine users. Studies suggest the effect is temporary. {{As of|2013}}, the effect of low-dose or acute use of morphine on the endocrine system is unclear.<ref name="pmid23414717">{{cite journal | author = Brennan MJ | title = The effect of opioid therapy on endocrine function | journal = Am. J. Med. | volume = 126 | issue = 3 Suppl 1 | pages = S12–8 |date=March 2013 | pmid = 23414717 | doi = 10.1016/j.amjmed.2012.12.001 }}</ref><ref name="pmid19193821">{{cite journal |vauthors=Colameco S, Coren JS | title = Opioid-induced endocrinopathy | journal = J Am Osteopath Assoc | volume = 109 | issue = 1 | pages = 20–5 |date=January 2009 | pmid = 19193821 | doi = }}</ref>

=== Effects on human performance ===
Most reviews conclude that opioids produce minimal impairment of human performance on tests of sensory, motor, or attentional abilities. However, recent studies have been able to show some impairments caused by morphine, which is not surprising, given that morphine is a [[central nervous system]] [[depressant]]. Morphine has resulted in impaired functioning on critical flicker frequency (a measure of overall CNS arousal) and impaired performance on the [[Maddox Wing]] test (a measure of deviation of the visual axes of the eyes). Few studies have investigated the effects of morphine on motor abilities; a high dose of morphine can impair finger tapping and the ability to maintain a low constant level of [[isometric exercise|isometric force]] (i.e. fine motor control is impaired),<ref name="pmid1755931">{{cite journal |vauthors=Kerr B, Hill H, Coda B, Calogero M, Chapman CR, Hunt E, Buffington V, Mackie A | title = Concentration-related effects of morphine on cognition and motor control in human subjects | journal = Neuropsychopharmacology | volume = 5 | issue = 3 | pages = 157–66 |date=November 1991 | pmid = 1755931 | doi = }}</ref> though no studies have shown a correlation between morphine and gross motor abilities.

In terms of [[cognitive]] abilities, one study has shown that morphine may have a negative impact on [[anterograde amnesia|anterograde]] and [[retrograde amnesia|retrograde memory]],<ref>{{cite journal |vauthors=Friswell J, Phillips C, Holding J, Morgan CJ, Brandner B, Curran HV |title=Acute effects of opioids on memory functions of healthy men and women |journal=Psychopharmacology (Berl.) |volume=198 |issue=2 |pages=243–50 |year=2008|pmid=18379759 |doi=10.1007/s00213-008-1123-x}}</ref> but these effects are minimal and transient. Overall, it seems that acute doses of opioids in non-tolerant subjects produce minor effects in some sensory and motor abilities, and perhaps also in [[attention]] and cognition. It is likely that the effects of morphine will be more pronounced in opioid-naive subjects than chronic opioid users.

In chronic opioid users, such as those on Chronic Opioid Analgesic Therapy (COAT) for managing severe, [[chronic pain]], behavioural testing has shown normal functioning on perception, cognition, coordination and behaviour in most cases. One recent study<ref>{{cite journal |vauthors=Galski T, Williams JB, Ehle HT |title=Effects of opioids on driving ability |journal=J Pain Symptom Manage |volume=19 |issue=3 |pages=200–8 |year=2000 |pmid=10760625 |doi=10.1016/S0885-3924(99)00158-X}}</ref> analysed COAT patients to determine whether they were able to safely operate a motor vehicle. The findings from this study suggest that stable opioid use does not significantly impair abilities inherent in driving (this includes physical, cognitive and perceptual skills). COAT patients showed rapid completion of tasks that require speed of responding for successful performance (e.g., [[Rey Complex Figure]] Test) but made more errors than controls. COAT patients showed no deficits in visual-spatial perception and organization (as shown in the [[Wechsler Adult Intelligence Scale|WAIS-R]] Block Design Test) but did show impaired immediate and short-term visual memory (as shown on the Rey Complex Figure Test&nbsp;– Recall). These patients showed no impairments in higher order cognitive abilities (i.e., Planning). COAT patients appeared to have difficulty following instructions and showed a propensity toward impulsive behaviour, yet this did not reach statistical significance. It is important to note that this study reveals that COAT patients have no domain-specific deficits, which supports the notion that chronic opioid use has minor effects on [[Psychomotor learning|psychomotor]], [[cognitive]], or [[neuropsychological]] functioning.

=== Reinforcement disorders ===

==== Addiction ====

[[File:Santiago Rusinol Before the Morphine.jpg|thumb|''Before the Morphine'' by [[Santiago Rusiñol]]]]

Morphine is a highly [[addictive]] substance. In controlled studies comparing the physiological and subjective effects of [[heroin]] and morphine in individuals formerly addicted to opiates, subjects showed no preference for one drug over the other. Equipotent, injected doses had comparable action courses, with no difference in subjects' self-rated feelings of euphoria, ambition, nervousness, relaxation, drowsiness, or sleepiness.<ref name="martin and fraser" /> Short-term addiction studies by the same researchers demonstrated that tolerance developed at a similar rate to both heroin and morphine. When compared to the opioids [[hydromorphone]], [[fentanyl]], [[oxycodone]], and [[pethidine]]/[[meperidine]], former addicts showed a strong preference for heroin and morphine, suggesting that heroin and morphine are particularly susceptible to abuse and addiction. Morphine and heroin were also much more likely to produce euphoria and other positive subjective effects when compared to these other opioids.<ref name="martin and fraser" /> The choice of heroin and morphine over other opioids by former drug addicts may also be because heroin (also known as morphine diacetate, diamorphine, or diacetyl morphine) is an ester of morphine and a morphine [[prodrug]], essentially meaning they are identical drugs ''in vivo''. Heroin is converted to morphine before binding to the [[opioid receptor]]s in the brain and spinal cord, where morphine causes the subjective effects, which is what the addicted individuals are seeking.<ref name="urlDrugFacts: Heroin | National Institute on Drug Abuse (NIDA)">{{cite web | url = http://www.nida.nih.gov/infofacts/heroin.html | title = Heroin | author = National Institute on Drug Abuse (NIDA) | date = April 2013 | work = DrugFacts | publisher = U.S. National Institutes of Health }}</ref>

==== Tolerance ====
Several hypotheses are given about how tolerance develops, including opioid receptor [[phosphorylation]] (which would change the receptor conformation), functional decoupling of receptors from [[G-proteins]] (leading to receptor desensitization),<ref>{{cite journal |vauthors=Roshanpour M, Ghasemi M, Riazi K, Rafiei-Tabatabaei N, Ghahremani MH, Dehpour AR |title=Tolerance to the anticonvulsant effect of morphine in mice: blockage by ultra-low dose naltrexone |journal=Epilepsy Res. |volume=83 |issue=2–3 |pages=261–4 |year=2009|pmid=19059761 |doi=10.1016/j.eplepsyres.2008.10.011}}</ref> μ-opioid receptor internalization or receptor down-regulation (reducing the number of available receptors for morphine to act on), and upregulation of the [[cyclic adenosine monophosphate|cAMP]] pathway (a counterregulatory mechanism to opioid effects) (For a review of these processes, see Koch and Hollt.<ref>{{cite journal |vauthors=Koch T, Höllt V |title=Role of receptor internalization in opioid tolerance and dependence |journal=Pharmacol. Ther. |volume=117 |issue=2 |pages=199–206 |year=2008|pmid=18076994 |doi=10.1016/j.pharmthera.2007.10.003}}</ref>) [[Cholecystokinin|CCK]] might mediate some counter-regulatory pathways responsible for opioid tolerance. CCK-antagonist drugs, specifically [[proglumide]], have been shown to slow the development of tolerance to morphine.

==== Dependence and withdrawal ====
{{See also|Opioid dependence|Opioid withdrawal}}
Cessation of dosing with morphine creates the prototypical opioid withdrawal syndrome, which, unlike that of [[barbiturates]], [[benzodiazepines]], [[ethanol|alcohol]], or sedative-hypnotics, is not fatal by itself in neurologically healthy patients without heart or lung problems.

Acute morphine withdrawal, along with that of any other opioid, proceeds through a number of stages. Other opioids differ in the intensity and length of each, and weak opioids and mixed agonist-antagonists may have acute withdrawal syndromes that do not reach the highest level. As commonly cited{{by whom|date=November 2010}}, they are:
* '''Stage I''', 6 to 14 hours after last dose: Drug craving, anxiety, irritability, perspiration, and mild to moderate [[dysphoria]] {{Citation needed|date=March 2015}}
* '''Stage II''', 14 to 18 hours after last dose: Yawning, heavy perspiration, mild depression, lacrimation, crying, headaches, runny nose, [[dysphoria]], also intensification of the above symptoms, "yen sleep" (a waking trance-like state) {{clarify|date=October 2010}}
* '''Stage III''', 16 to 24 hours after last dose: [[Rhinorrhea]] (runny nose) and increase in other of the above, dilated pupils, piloerection (goose bumps – giving the name 'cold turkey'), muscle twitches, hot flashes, cold flashes, aching bones and muscles, loss of appetite, and the beginning of intestinal cramping {{Citation needed|date=March 2015}}
* '''Stage IV''', 24 to 36 hours after last dose: Increase in all of the above including severe cramping and involuntary leg movements ("kicking the habit" also called [[restless leg syndrome]]), loose stool, insomnia, elevation of blood pressure, moderate elevation in body temperature, increase in frequency of breathing and tidal volume, [[tachycardia]] (elevated pulse), restlessness, nausea {{Citation needed|date=March 2015}}
* '''Stage V''', 36 to 72 hours after last dose: Increase in the above, fetal position, vomiting, free and frequent liquid diarrhea, which sometimes can accelerate the time of passage of food from mouth to out of system, weight loss of 2 to 5&nbsp;kg per 24 hours, increased [[White blood cell|white cell count]], and other blood changes {{Citation needed|date=March 2015}}
* '''Stage VI''', after completion of above: Recovery of appetite and normal bowel function, beginning of transition to postacute and chronic symptoms that are mainly psychological, but may also include increased sensitivity to pain, hypertension, [[colitis]] or other gastrointestinal afflictions related to motility, and problems with weight control in either direction {{Citation needed|date=March 2015}}

In advanced stages of withdrawal, ultrasonographic evidence of pancreatitis has been demonstrated in some patients and is presumably attributed to spasm of the pancreatic [[sphincter of Oddi]].<ref>[http://www.livestrong.com/article/68215-opiate-withdrawal-stages/]</ref>

The withdrawal symptoms associated with morphine addiction are usually experienced shortly before the time of the next scheduled dose, sometimes within as early as a few hours (usually 6–12 hours) after the last administration. Early symptoms include watery eyes, insomnia, diarrhea, runny nose, yawning, [[dysphoria]], sweating, and in some cases a strong drug craving. Severe headache, restlessness, irritability, loss of appetite, body aches, severe abdominal pain, nausea and vomiting, tremors, and even stronger and more intense drug craving appear as the syndrome progresses. Severe depression and vomiting are very common. During the acute withdrawal period, systolic and diastolic blood pressures increase, usually beyond premorphine levels, and heart rate increases,<ref name="Chan, Irvine, and White">{{cite journal |vauthors=Chan R, Irvine R, White J |title=Cardiovascular changes during morphine administration and spontaneous withdrawal in the rat |journal=Eur. J. Pharmacol. |volume=368 |issue=1 |pages=25–33 |year=1999 |pmid=10096766 |doi=10.1016/S0014-2999(98)00984-4}}</ref> which have potential to cause a heart attack, blood clot, or stroke.

Chills or cold flashes with goose bumps ("cold turkey") alternating with flushing (hot flashes), kicking movements of the legs ("kicking the habit"<ref name="urlDrugFacts: Heroin | National Institute on Drug Abuse (NIDA)" />) and excessive sweating are also characteristic symptoms.<ref name="urlDrugs and Human Performance FACT SHEETS – Morphine (and Heroin)">{{cite web | url = http://www.nhtsa.dot.gov/People/injury/research/job185drugs/morphine.htm | title = Morphine (and Heroin) | date = | work = Drugs and Human Performance Fact Sheets | publisher = U.S. National Traffic Safety Administration }}</ref> Severe pains in the bones and muscles of the back and extremities occur, as do muscle spasms. At any point during this process, a suitable narcotic can be administered that will dramatically reverse the withdrawal symptoms. Major withdrawal symptoms peak between 48 and 96 hours after the last dose and subside after about 8 to 12 days. Sudden withdrawal by heavily dependent users who are in poor health is very rarely fatal. Morphine withdrawal is considered less dangerous than alcohol, barbiturate, or benzodiazepine withdrawal.<ref>{{cite web|url=http://www.justice.gov/dea/concern/narcotics.html |title=Narcotics |work=DEA Briefs & Background, Drugs and Drug Abuse, Drug Descriptions |publisher=U.S. Drug Enforcement Administration |deadurl=unfit |archiveurl=https://web.archive.org/web/20120114150200/http://www.justice.gov/dea/concern/narcotics.html |archivedate=14 January 2012 }}</ref><ref>{{Cite book | author = Dalrymple T | authorlink = Theodore Dalrymple | title = Romancing Opiates: Pharmacological Lies and the Addiction Bureaucracy | publisher = Encounter | year = 2006 | pages = 160 | url = http://www.encounterbooks.com/books/romancingopiates/ | isbn = 978-1-59403-087-1 }}</ref>

The psychological dependence associated with morphine [[Substance use disorder|addiction]] is complex and protracted. Long after the physical need for morphine has passed, the addict will usually continue to think and talk about the use of morphine (or other drugs) and feel strange or overwhelmed coping with daily activities without being under the influence of morphine. Psychological withdrawal from morphine is usually a very long and painful process.<ref name="pmid11594449">{{cite journal |vauthors=Anraku T, Ikegaya Y, Matsuki N, Nishiyama N | title = Withdrawal from chronic morphine administration causes prolonged enhancement of immobility in rat forced swimming test | journal = Psychopharmacology (Berl.) | volume = 157 | issue = 2 | pages = 217–20 |date=September 2001 | pmid = 11594449 | doi = 10.1007/s002130100793 }}</ref>{{Unreliable medical source|date=January 2014|sure=y}} Addicts often suffer severe depression, anxiety, insomnia, mood swings, amnesia (forgetfulness), low self-esteem, confusion, paranoia, and other psychological disorders. Without intervention, the syndrome will run its course, and most of the overt physical symptoms will disappear within 7 to 10 days including psychological dependence. A high probability of relapse exists after morphine withdrawal when neither the physical environment nor the behavioral motivators that contributed to the abuse have been altered. Testimony to morphine's addictive and reinforcing nature is its relapse rate. Abusers of morphine (and heroin) have one of the highest relapse rates among all drug users, ranging up to 98% in the estimation of some medical experts.<ref>{{Cite book | author = O'Neil MJ | title = The Merck index : an encyclopedia of chemicals, drugs, and biological | year = 2006 | publisher = Merck | location = Whitehouse Station, N.J. | isbn = 0-911910-00-X | pages = }}</ref>

== Overdose ==
{{See also|Opioid overdose}}
A large [[overdose]] can cause [[asphyxia]] and death by respiratory depression if the person does not receive medical attention immediately.<ref name=Duldner>[https://www.nlm.nih.gov/medlineplus/ency/article/002502.htm MedlinePlus – Morphine overdose] Update Date: 2 March 2009. Updated by: John E. Duldner, Jr., MD</ref> Overdose treatment includes the administration of [[naloxone]]. The latter completely reverses morphine's effects, but may result in immediate onset of withdrawal in opiate-addicted subjects. Multiple doses may be needed.<ref name=Duldner />

The [[lethal dose#Lowest lethal dose|minimum lethal dose]] is 200&nbsp;mg, but in case of hypersensitivity, 60&nbsp;mg can bring sudden death. In serious drug dependency (high tolerance), 2000–3000&nbsp;mg per day can be tolerated.<ref>{{cite book | author = Macchiarelli L, Arbarello Cave Bondi P. Di Luca NM, Feola T | title = Medicina Legale (compendio) | edition = II | publisher = Minerva Medica Publications | location = Italy, Turin | year = 2002}}</ref>

== Pharmacology ==

=== Pharmacodynamics ===
{{Main|Opioid receptor}}
{{Update|section|inaccurate=yes|date=July 2014}}
Endogenous opioids include [[endorphin]]s, [[enkephalin]]s, [[dynorphin]]s, and even morphine itself. Morphine appears to mimic endorphins. Endorphins, a contraction of the term endogenous morphines, are responsible for [[analgesia]] (reducing pain), causing sleepiness, and feelings of pleasure. They can be released in response to pain, strenuous exercise, orgasm, or excitement.

Morphine is the prototype narcotic drug and is the standard against which all other opioids are tested. It interacts predominantly with the μ–δ-opioid (Mu-Delta) [[GPCR oligomer|receptor heteromer]].<ref>{{cite journal |vauthors=Yekkirala AS, Kalyuzhny AE, Portoghese PS |title=Standard opioid agonists activate heteromeric opioid receptors: evidence for morphine and [d-Ala(2)-MePhe(4)-Glyol(5)]enkephalin as selective μ-δ agonists |journal=ACS Chem Neurosci |volume=1 |issue=2 |pages=146–54 |year=2010 |pmid=22816017 |doi=10.1021/cn9000236 |url= |pmc=3398540}}</ref><ref>{{cite journal |vauthors=Yekkirala AS, Banks ML, Lunzer MM, Negus SS, Rice KC, Portoghese PS |title=Clinically employed opioid analgesics produce antinociception via μ-δ opioid receptor heteromers in Rhesus monkeys |journal=ACS Chem Neurosci |volume=3 |issue=9 |pages=720–7 |year=2012 |pmid=23019498 |pmc=3447399 |doi=10.1021/cn300049m |url=}}</ref> The μ-binding sites are discretely distributed in the [[human brain]], with high densities in the posterior [[amygdala]], [[hypothalamus]], [[thalamus]], [[nucleus caudatus]], [[putamen]], and certain cortical areas. They are also found on the [[chemical synapse|terminal axons]] of primary afferents within laminae [[posteromarginal nucleus|I]] and II ([[substantia gelatinosa of Rolando|substantia gelatinosa]]) of the spinal cord and in the spinal nucleus of the [[trigeminal nerve]].<ref name="rxlist.com">{{cite web | url = http://www.rxlist.com/cgi/generic/ms_cp.htm | title = MS-Contin (Morphine Sulfate Controlled-Release) Drug Information: Clinical Pharmacology | date = | work = Prescribing Information | publisher = RxList }}</ref>

Morphine is a [[phenanthrene]] [[opioid receptor]] [[receptor agonist|agonist]]&nbsp;– its main effect is binding to and activating the [[mu opioid receptor|μ-opioid]] receptors in the [[central nervous system]]. In clinical settings, morphine exerts its principal pharmacological effect on the central nervous system and [[Human gastrointestinal tract|gastrointestinal tract]]. Its primary actions of therapeutic value are analgesia and sedation. Activation of the [[mu opioid receptor|μ-opioid]] receptors is associated with analgesia, sedation, [[Euphoria (emotion)|euphoria]], physical [[Chemical dependency|dependence]], and [[respiratory depression]]. Morphine is a rapid-acting narcotic, and it is known to bind very strongly to the [[mu opioid receptor|μ-opioid]] receptors, and for this reason, it often has a higher incidence of euphoria/dysphoria, respiratory depression, sedation, pruritus, tolerance, and physical and psychological dependence when compared to other opioids at equianalgesic doses. Morphine is also a [[kappa opioid receptor|κ-opioid]] and [[delta opioid receptor|δ-opioid]] receptor agonist, κ-opioid's action is associated with spinal analgesia, [[miosis]] (pinpoint pupils) and [[psychotomimetic]] effects. δ-Opioid is thought to play a role in analgesia.<ref name="rxlist.com" /> Although morphine does not bind to the [[sigma receptor|σ-receptor]], it has been shown that σ-agonists, such as (+)-[[pentazocine]], inhibit morphine analgesia, and σ-antagonists enhance morphine analgesia,<ref>{{cite journal |vauthors=Chien CC, Pasternak GW |title=Sigma antagonists potentiate opioid analgesia in rats |journal=Neurosci. Lett. |volume=190 |issue=2 |pages=137–9 |year=1995 |pmid=7644123 |doi=10.1016/0304-3940(95)11504-P}}</ref> suggesting downstream involvement of the σ-receptor in the actions of morphine.

The effects of morphine can be countered with opioid [[receptor antagonist|antagonists]] such as [[naloxone]] and [[naltrexone]]; the development of tolerance to morphine may be inhibited by [[NMDA]] antagonists such as [[ketamine]] or [[dextromethorphan]].<ref>{{cite journal |vauthors=Herman BH, Vocci F, Bridge P |title=The effects of NMDA receptor antagonists and nitric oxide synthase inhibitors on opioid tolerance and withdrawal. Medication development issues for opiate addiction |journal=Neuropsychopharmacology |volume=13 |issue=4 |pages=269–93 |year=1995 |pmid=8747752 |doi=10.1016/0893-133X(95)00140-9}}</ref> The rotation of morphine with chemically dissimilar opioids in the long-term treatment of pain will slow down the growth of tolerance in the longer run, particularly agents known to have significantly incomplete cross-tolerance with morphine such as [[levorphanol]], [[ketobemidone]], [[piritramide]], and [[methadone]] and its derivatives; all of these drugs also have NMDA antagonist properties. It is believed that the strong opioid with the most incomplete cross-tolerance with morphine is either methadone or [[dextromoramide]].

==== Gene expression ====
Studies have shown that morphine can alter the expression of a number of [[genes]]. A single injection of morphine has been shown to alter the expression of two major groups of genes, for proteins involved in [[mitochondria]]l respiration and for [[cytoskeleton]]-related proteins.<ref>{{cite journal |vauthors=Loguinov A, Anderson L, Crosby G, Yukhananov R |title=Gene expression following acute morphine administration |journal=Physiol Genomics |volume=6 |issue=3 |pages=169–81 |year=2001 |pmid=11526201}}</ref>

==== Effects on the immune system ====
Morphine has long been known to act on receptors expressed on cells of the [[central nervous system]] resulting in pain relief and [[analgesia]]. In the 1970s and '80s, evidence suggesting that opioid drug addicts show increased risk of infection (such as increased [[pneumonia]], [[tuberculosis]], and [[HIV/AIDS]]) led scientists to believe that morphine may also affect the [[immune system]]. This possibility increased interest in the effect of chronic morphine use on the immune system.

The first step of determining that morphine may affect the immune system was to establish that the opiate receptors known to be expressed on cells of the central nervous system are also expressed on cells of the immune system. One study successfully showed that [[dendritic cells]], part of the innate immune system, display opiate receptors. Dendritic cells are responsible for producing [[cytokine]]s, which are the tools for communication in the immune system. This same study showed that dendritic cells chronically treated with morphine during their differentiation produce more [[interleukin-12]] (IL-12), a cytokine responsible for promoting the proliferation, growth, and differentiation of T-cells (another cell of the adaptive immune system) and less [[interleukin-10]] (IL-10), a cytokine responsible for promoting a B-cell immune response (B cells produce antibodies to fight off infection).<ref name="messmer 2006">{{cite journal |vauthors=Messmer D, Hatsukari I, Hitosugi N, Schmidt-Wolf IG, Singhal PC |title=Morphine reciprocally regulates IL-10 and IL-12 production by monocyte-derived human dendritic cells and enhances T cell activation |journal=Mol. Med. |volume=12 |issue=11–12 |pages=284–90 |year=2006 |pmid=17380193 |pmc=1829197 |doi=10.2119/2006-00043.Messmer}}</ref>

This regulation of cytokines appear to occur via the [[p38 MAPK pathway|p38 MAPKs (mitogen-activated protein kinase)-dependent pathway]]. Usually, the p38 within the dendritic cell expresses [[TLR 4]] (toll-like receptor 4), which is activated through the ligand LPS ([[lipopolysaccharide]]). This causes the p38 MAPK to be [[phosphorylation|phosphorylated]]. This phosphorylation activates the [[p38 mitogen-activated protein kinases|p38 MAPK]] to begin producing IL-10 and IL-12. When the dendritic cells are chronically exposed to morphine during their differentiation process then treated with LPS, the production of cytokines is different. Once treated with morphine, the p38 MAPK does not produce IL-10, instead favoring production of IL-12. The exact mechanism through which the production of one cytokine is increased in favor over another is not known. Most likely, the morphine causes increased phosphorylation of the p38 MAPK. Transcriptional level interactions between IL-10 and IL-12 may further increase the production of IL-12 once IL-10 is not being produced. This increased production of IL-12 causes increased T-cell immune response.

Further studies on the effects of morphine on the immune system have shown that morphine influences the production of [[neutrophils]] and other [[cytokines]]. Since cytokines are produced as part of the immediate immunological response ([[inflammation]]), it has been suggested that they may also influence pain. In this way, cytokines may be a logical target for analgesic development. Recently, one study has used an animal model (hind-paw incision) to observe the effects of morphine administration on the acute immunological response. Following hind-paw incision, pain thresholds and cytokine production were measured. Normally, cytokine production in and around the wounded area increases in order to fight [[infection]] and control healing (and, possibly, to control pain), but pre-incisional morphine administration (0.1–10.0&nbsp;mg/kg) reduced the number of cytokines found around the wound in a dose-dependent manner. The authors suggest that morphine administration in the acute post-injury period may reduce resistance to infection and may impair the healing of the wound.<ref name="pmid17908329">{{cite journal |vauthors=Clark JD, Shi X, Li X, Qiao Y, Liang D, Angst MS, Yeomans DC | title = Morphine reduces local cytokine expression and neutrophil infiltration after incision | journal = Mol Pain | volume = 3 | issue = | pages = 28 | year = 2007 | pmid = 17908329 | pmc = 2096620 | doi = 10.1186/1744-8069-3-28 }}</ref>

=== Pharmacokinetics ===

==== Absorption and metabolism ====
Morphine can be taken [[oral administration|orally]], [[Sublingual administration|sublingually]], [[Buccal space|bucally]], [[rectal administration|rectally]], [[subcutaneous injection|subcutaneously]], [[Insufflation (medicine)|intranasally]], [[intravenous]]ly, [[intrathecal]]ly or [[epidural]]ly and inhaled via a nebulizer. On the streets, it is becoming more common to inhale ("[[Chasing the Dragon]]"), but, for medical purposes, intravenous (IV) injection is the most common method of administration. Morphine is subject to extensive [[first-pass metabolism]] (a large proportion is broken down in the liver), so, if taken orally, only 40–50% of the dose reaches the central nervous system. Resultant plasma levels after subcutaneous (SC), intramuscular (IM), and IV injection are all comparable. After IM or SC injections, morphine plasma levels peak in approximately 20 minutes, and, after oral administration, levels peak in approximately 30 minutes.<ref>{{cite journal |vauthors=Trescot AM, Datta S, Lee M, Hansen H |title=Opioid pharmacology |journal=Pain Physician |volume=11 |issue=2 Suppl |pages=S133–53 |year=2008 |pmid=18443637}}</ref> Morphine is [[metabolised]] primarily in the [[liver]] and approximately 87% of a dose of morphine is excreted in the [[urine]] within 72 hours of administration. Morphine is metabolized primarily into [[morphine-3-glucuronide]] (M3G) and [[morphine-6-glucuronide]] (M6G)<ref>{{cite journal|author1=Kilpatrick G.J. |author2=Smith T.W. |title=Morphine-6-glucuronide: actions and mechanisms|journal=Med. Res. Rev.|year=2005|volume=25|issue=5|pages=521–544|pmid=15952175|doi=10.1002/med.20035}}</ref> via [[glucuronidation]] by phase II metabolism enzyme [[UGT2B7|UDP-glucuronosyl transferase-2B7]] (UGT2B7). About 60% of morphine is converted to M3G, and 6–10% is converted to M6G.<ref name="van Dorp" /> Not only does the metabolism occur in the liver but it may also take place in the brain and the kidneys. M3G does not undergo opioid receptor binding and has no analgesic effect. M6G binds to μ-receptors and is half as potent an analgesic as morphine in humans.<ref name="van Dorp">{{cite journal|vauthors=van Dorp EL, Romberg R, Sarton E, Bovill JG, Dahan A |title=Morphine-6-glucuronide: morphine's successor for postoperative pain relief?|journal=Anesthesia and Analgesia|volume=102|issue=6|pages=1789–1797|pmid=16717327|url=http://www.anesthesia-analgesia.org/cgi/content/full/102/6/1789|doi=10.1213/01.ane.0000217197.96784.c3|year=2006}}</ref> Morphine may also be metabolized into small amounts of [[normorphine]], [[codeine]], and [[hydromorphone]]. Metabolism rate is determined by gender, age, diet, genetic makeup, disease state (if any), and use of other medications. The elimination [[half-life]] of morphine is approximately 120 minutes, though there may be slight differences between men and women. Morphine can be stored in fat, and, thus, can be detectable even after death. Morphine can cross the [[blood–brain barrier]], but, because of poor lipid solubility, protein binding, rapid conjugation with glucuronic acid and ionization, it does not cross easily. [[Diacetylmorphine]], which is derived from morphine, crosses the blood–brain barrier more easily, making it more potent.<ref name="Jenkins AJ 2008">Jenkins AJ (2008) Pharmacokinetics of specific drugs. In Karch SB (''Ed''), ''Pharmacokinetics and pharmacodynamics of abused drugs''. CRC Press: Boca Raton.</ref>

==== Extended-release ====
{{Main|Extended-release morphine}}
There are [[Time release technology|extended-release]] formulations of orally administered morphine whose effect last longer, which can be given once per day. Brand names for this formulation of morphine include Avinza,<ref name=maryland /> Kadian,<ref name=maryland /> MS Contin<ref name=maryland>{{cite web|url=https://umm.edu/health/medical/drug-notes/notes/morphine-slow-release-by-mouth|title=Morphine, slow release (By mouth)|website=[[University of Maryland Medical Center]]}}</ref> and Dolcontin.<ref name="PedersenFredheim2015">{{cite journal|last1=Pedersen|first1=L|last2=Fredheim|first2=OMS|title=Opioids for Chronic Noncancer Pain: Still No Evidence for Superiority of Sustained-Release Opioids|journal=Clinical Pharmacology & Therapeutics|volume=97|issue=2|year=2015|pages=114–115|issn=0009-9236|doi=10.1002/cpt.26}} Last reviewed on 11/18/2015</ref> For constant pain, the relieving effect of extended-release morphine given once (for Kadian)<ref name=medscape>{{cite web|url=http://reference.medscape.com/drug/ms-contin-astramorph-morphine-343319|title=Dosing & Uses|website=[[Medscape]]|accessdate=2015-12-21}}</ref> or twice (for MS Contin)<ref name=medscape /> every 24 hours is roughly the same as multiple administrations of ''immediate release'' (or "regular") morphine.<ref name=northwestern>{{cite web|url=http://endoflife.northwestern.edu/pain_management/morphine.pdf|title=EndLink: An Internet-based End of Life Care Education Program – Morphine Dosing|website=[[Northwestern University]]}}</ref> Extended-release morphine can be administered together with "rescue doses" of immediate-release morphine as needed in case of breakthrough pain, each generally consisting of 5% to 15% of the 24-hour extended-release dosage.<ref name=northwestern />

==== Detection in body fluids ====
Morphine and its major metabolites, morphine-3-glucuronide and morphine-6-glucuronide, can be detected in blood, plasma, hair, and urine using an [[immunoassay]]. [[Chromatography]] can be used to test for each of these substances individually. Some testing procedures [[hydrolysis|hydrolyze]] metabolic products into morphine before the immunoassay, which must be considered when comparing morphine levels in separately published results. Morphine can also be isolated from whole blood samples by [[solid phase extraction]] (SPE) and detected using [[liquid chromatography-mass spectrometry]] (LC-MS).

Ingestion of codeine or food containing poppy seeds can cause false positives.<ref>{{Cite book | author = Baselt RC | title = Disposition of Toxic Drugs and Chemicals in Man | year = 2008 | edition = 8th | publisher = Biomedical Publications | location = Foster City, CA | isbn = 0-9626523-7-7 | pages = 1057–1062 }}</ref>

A 1999 review estimated that relatively low doses of heroin (which metabolizes immediately into morphine) are detectable by standard urine tests for 1-1.5 days after use.<ref name="pmid11484423">{{cite journal |vauthors=Vandevenne M, Vandenbussche H, Verstraete A | title = Detection time of drugs of abuse in urine | journal = Acta Clin Belg | volume = 55 | issue = 6 | pages = 323–33 | year = 2000 | pmid = 11484423 | doi = }}</ref> A 2009 review determined that, when the [[analyte]] is morphine and the [[limit of detection]] is 1{{space}}ng/ml, a 20{{space}}mg intravenous (IV) dose of morphine is detectable for 12–24 hours. A limit of detection of 0.6{{space}}ng/ml had similar results.<ref name="pmid15228165">{{cite journal | author = Verstraete AG | title = Detection times of drugs of abuse in blood, urine, and oral fluid | journal = Ther Drug Monit | volume = 26 | issue = 2 | pages = 200–5 |date=April 2004 | pmid = 15228165 | doi =10.1097/00007691-200404000-00020 }}</ref>

== Natural occurrence ==
{{See also|Opium}}
[[File:Slaapbol R0017600.JPG|thumb|A freshly-scored opium poppy seedpod bleeding latex.]]
Morphine is the most abundant opiate found in [[opium]], the dried [[latex]] extracted by shallowly scoring the unripe seedpods of the ''[[Papaver somniferum]]'' poppy. Morphine is generally 8–14% of the dry weight of opium,<ref name=Kapoor>{{cite book |author = Kapoor L | title = Opium Poppy: Botany, Chemistry, and Pharmacology | year = 1995 | publisher = CRC Press | location = United States | isbn = 1-56024-923-4 | pages = 164 }}</ref> although specially bred [[cultivar]]s reach 26% or produce little morphine at all (under 1%, perhaps down to 0.04%). The latter varieties, including the 'Przemko' and 'Norman' cultivars of the opium poppy, are used to produce two other alkaloids, [[thebaine]] and [[oripavine]], which are used in the manufacture of semi-synthetic and synthetic opioids like [[oxycodone]] and [[etorphine]] and some other types of drugs. ''[[Papaver bracteatum|P. bracteatum]]'' does not contain morphine or [[codeine]], or other narcotic [[phenanthrene]]-type, alkaloids. This species is rather a source of [[thebaine]].<ref name="pmid925935">{{cite journal |vauthors=Vincent PG, Bare CE, Gentner WA | title = Thebaine content of selections of Papaver bracteatum Lindl. at different ages | journal = J Pharm Sci | volume = 66 | issue = 12 | pages = 1716–9 |date=December 1977 | pmid = 925935 | doi = 10.1002/jps.2600661215 }}</ref> Occurrence of morphine in other [[Papaverales]] and [[Papaveraceae]], as well as in some species of [[hops]] and [[mulberry]] trees has not been confirmed. Morphine is produced most predominantly early in the life cycle of the plant. Past the optimum point for extraction, various processes in the plant produce codeine, [[thebaine]], and in some cases negligible amounts of [[hydromorphone]], [[dihydromorphine]], [[dihydrocodeine]], tetrahydro-thebaine, and [[hydrocodone]] (these compounds are rather synthesized from thebaine and oripavine). The human body produces [[endorphins]],<ref>{{MerriamWebsterDictionary|endorphin}}</ref> which are [[endogenous]] [[opioid]] [[peptide]]s that function as [[neurotransmitters]] and have similar effects.<ref>{{Cite book | author = Stewart O | title = Functional Neuroscience | year = 2000 | publisher = Springer | location = New York | isbn = 0-387-98543-3 | page = 116 | url = https://books.google.com/?id=nNH3p29wjK4C&pg=PA116&dq=endorphins+neurotransmitter#v=onepage&q=endorphins%20neurotransmitter&f=false }}</ref>

== Physical and chemical properties ==
[[File:Benzylisoquinoline structure in Morphine.svg|thumb|Chemical structure of morphine. The [[benzylisoquinoline]] backbone is shown in green.]]
[[File:Morphine stereo structure.svg|thumb|Same structure with correct 3D configuration; backbone in blue.]]

Morphine is a [[benzylisoquinoline]] alkaloid with two additional ring closures. It has:
* A rigid [[pentacyclic]] structure consisting of a [[benzene]] ring (A), two partially unsaturated [[cyclohexane]] rings (B and C), a [[piperidine]] ring (D) and a [[tetrahydrofuran]] ring (E). Rings A, B and C are the [[phenanthrene]] ring system. This ring system has little conformational flexibility.
* Two hydroxyl functional groups: a C3-[[phenol]]ic OH (p''K''<sub>a</sub> 9.9) and a C6-[[allyl]]ic [[hydroxyl|OH]],
* An [[ether]] linkage between C4 and C5,
* [[Saturated and unsaturated compounds|Unsaturation]] between C7 and C8,
* A basic, tertiary [[amine]] function at position 17,
* 5 centers of [[chirality]] (C5, C6, C9, C13 and C14) with morphine exhibiting a high degree of [[stereoselectivity]] of analgesic action.<ref name="urlwww.auburn.edu">{{cite web | url = http://www.auburn.edu/~deruija/opioids_morphine.pdf | title = Narcotic analgesics: morphine and "peripherally modified" morphine analogs | author = DeRuiter J | date = Fall 2000 | format = PDF | work = Principles of Drug Action 2 | publisher = Auburn University }}</ref>

Most of the licit morphine produced is used to make [[codeine]] by methylation. It is also a precursor for many drugs including [[heroin]] (3,6-diacetylmorphine), [[hydromorphone]] (dihydromorphinone), and [[oxymorphone]] (14-hydroxydihydromorphinone); many morphine derivatives can also be manufactured using [[thebaine]] or codeine as a starting material. Replacement of the ''N''-methyl group of morphine with an ''N''-phenylethyl group results in a product that is 18 times more powerful than morphine in its opiate agonist potency. Combining this modification with the replacement of the 6-[[hydroxyl]] with a 6-[[methylene group]] produces a compound some 1,443 times more potent than morphine, stronger than the [[Bentley compounds]] such as [[etorphine]] (M99, the Immobilon tranquilliser dart) by some measures.

The structure-activity relationship of morphine has been extensively studied. As a result of the extensive study and use of this molecule, more than 250 morphine derivatives (also counting codeine and related drugs) have been developed since the last quarter of the 19th century. These drugs range from 25% the analgesic strength of codeine (or slightly more than 2% of the strength of morphine) to several thousand times the strength of morphine, to powerful opioid antagonists, including [[naloxone]] (Narcan), [[naltrexone]] (Trexan), [[diprenorphine]] (M5050, the reversing agent for the Immobilon dart) and [[nalorphine]] (Nalline). Some opioid agonist-antagonists, partial agonists, and inverse agonists are also derived from morphine. The receptor-activation profile of the semi-synthetic morphine derivatives varies widely and some, like [[apomorphine]] are devoid of narcotic effects.

Morphine and most of its derivatives do not exhibit optical isomerism, although some more distant relatives like the morphinan series (levorphanol, dextorphan and the racemic parent chemical dromoran) do, and as noted above stereoselectivity in vivo is an important issue.

Morphine-derived [[agonist–antagonist]] drugs have also been developed. Elements of the morphine structure have been used to create completely synthetic drugs such as the [[morphinan]] family ([[levorphanol]], [[dextromethorphan]] and others) and other groups that have many members with morphine-like qualities. The modification of morphine and the aforementioned synthetics has also given rise to non-narcotic drugs with other uses such as emetics, stimulants, antitussives, anticholinergics, muscle relaxants, local anaesthetics, general anaesthetics, and others.

Most semi-synthetic opioids, both of the morphine and [[codeine]] subgroups, are created by modifying one or more of the following:
* Halogenating or making other modifications at positions 1 or 2 on the morphine carbon skeleton.
* The methyl group that makes morphine into codeine can be removed or added back, or replaced with another functional group like ethyl and others to make codeine analogues of morphine-derived drugs and vice versa. Codeine analogues of morphine-based drugs often serve as prodrugs of the stronger drug, as in codeine and morphine, hydrocodone and hydromorphone, oxycodone and oxymorphone, nicocodeine and nicomorphine, dihydrocodeine and dihydromorphine, etc.
* Saturating, opening, or other changes to the bond between positions 7 and 8, as well as adding, removing, or modifying functional groups to these positions; saturating, reducing, eliminating, or otherwise modifying the 7–8 bond and attaching a functional group at 14 yields [[hydromorphinol]]; the oxidation of the hydroxyl group to a carbonyl and changing the 7–8 bond to single from double changes codeine into oxycodone.
* Attachment, removal or modification of functional groups to positions 3 or 6 (dihydrocodeine and related, hydrocodone, nicomorphine); in the case of moving the methyl functional group from position 3 to 6, codeine becomes [[heterocodeine]], which is 72 times stronger, and therefore six times stronger than morphine
* Attachment of functional groups or other modification at position 14 (oxymorphone, oxycodone, naloxone)
* Modifications at positions 2, 4, 5 or 17, usually along with other changes to the molecule elsewhere on the morphine skeleton. Often this is done with drugs produced by catalytic reduction, hydrogenation, oxidation, or the like, producing strong derivatives of morphine and codeine.

{| border="1" cellspacing="0" cellpadding="3" style="margin: 0 0 0 0.5em; float: right; background: #FFFFFF; border-collapse: collapse; border-color: #C0C090;"
! {{chembox header}} | Structure and properties
|-
| [[Molar mass]]<ref name="CRC_85">{{Cite book | editor = Lide DR | title = CRC handbook of chemistry and physics: a ready-reference book of chemical and physical data | year = 2004 | edition = 85 | publisher = CRC Press | location = Boca Ratan Florida | isbn = 0-8493-0485-7 }}</ref>
| 285.338 g/mol
|-
| [[Index of refraction]], ''n''<sub>D</sub>
| ?
|-
| [[Acidity]] (p''K''<sub>a</sub>)<ref name="CRC_85" />
|
{|
| Step 1: 8.21 || at 25&nbsp;°C
|-
| Step 2: 9.85 || at 20&nbsp;°C
|}
|-
| [[Solubility]]<ref name="CRC_85" />
| 0.15 g/L at 20&nbsp;°C
|-
| [[Melting point]]<ref name="CRC_85" />
| 255&nbsp;°C
|-
| [[Boiling point]]<ref name="CRC_85" />
| 190&nbsp;°C sublimes
|-
|}

Both morphine and its hydrated form, C<span style="font-size:100%;"><sub>17</sub></span>H<span style="font-size:100%;"><sub>19</sub></span>NO<span style="font-size:100%;"><sub>3</sub></span>H<span style="font-size:100%;"><sub>2</sub></span>O, are sparingly soluble in water. In five liters of water, only one gram of the hydrate will dissolve. For this reason, pharmaceutical companies produce sulfate and hydrochloride salts of the drug, both of which are over 300 times more water-soluble than their parent molecule. Whereas the pH of a saturated morphine hydrate solution is 8.5, the salts are acidic. Since they derive from a strong acid but weak base, they are both at about pH = 5; as a consequence, the morphine salts are mixed with small amounts of [[Sodium hydroxide|NaOH]] to make them suitable for injection.<ref name="urlMorphine">{{cite web | url = http://www.emsb.qc.ca/laurenhill/science/morphine.html | title = Morphine | date = | work = LHA Science Page | publisher = LaurenHill Academy }}</ref>

A number of salts of morphine are used, with the most common in current clinical use being the hydrochloride, sulfate, tartrate, and citrate; less commonly methobromide, hydrobromide, hydroiodide, lactate, chloride, and bitartrate and the others listed below. Morphine diacetate, which is another name for heroin, is a Schedule I controlled substance, so it is not used clinically in the United States; it is a sanctioned medication in the [[United Kingdom]] and in [[Canada]] and some countries in Continental Europe, its use being particularly common (nearly to the degree of the hydrochloride salt) in the United Kingdom. Morphine meconate is a major form of the alkaloid in the poppy, as is morphine pectinate, nitrate, sulphate, and some others. Like codeine, dihydrocodeine and other (especially older) opiates, morphine has been used as the salicylate salt by some suppliers and can be easily compounded, imparting the therapeutic advantage of both the opioid and the [[NSAID]]; multiple [[barbiturate]] salts of morphine were also used in the past, as was/is morphine valerate, the salt of the acid being the active principle of [[valerian (herb)|valerian]]. [[Calcium morphenate]] is the intermediate in various latex and poppy-straw methods of morphine production, more rarely sodium morphenate takes its place. Morphine ascorbate and other salts such as the tannate, citrate, and acetate, phosphate, valerate and others may be present in poppy tea depending on the method of preparation. Morphine valerate produced industrially was one ingredient of a medication available for both oral and parenteral administration popular many years ago in Europe and elsewhere called Trivalin (not to be confused with the current, unrelated herbal preparation of the same name), which also included the valerates of [[caffeine]] and [[cocaine]], with a version containing codeine valerate as a fourth ingredient being distributed under the name Tetravalin.

Closely related to morphine are the opioids morphine-''N''-oxide (genomorphine), which is a pharmaceutical that is no longer in common use; and pseudomorphine, an alkaloid that exists in opium, form as degradation products of morphine.

The salts listed by the [[United States Drug Enforcement Administration]] for reporting purposes, in addition to a few others, are as follows:
{| class="talk collapsed collapsible"
|-
! Select forms of morphine as 'morphiniums' or ''N''-protonated cations of morphine, i.e. ionic salts & chemical form with freebase conversion ratios:
|- style="text-align: left;"
|
{| class="wikitable"
|-
! Salt or drug !! [[Controlled Substances Act|CSA]] schedule !! [[Administrative Controlled Substances Code Number|ACSCN]] !! Free base conversion ratio
|-
| Morphine (base)
| [[Schedule II (US)|II]]
| 9300
| 1
|-
| Morphine citrate
| [[Schedule II (US)|II]]
| 9300
| 0.81
|-
| Morphine bitartrate
| [[Schedule II (US)|II]]
| 9300
| 0.66
|-
| Morphine stearate
| [[Schedule II (US)|II]]
| 9300
| 0.51
|-
| Morphine phthalate
| [[Schedule II (US)|II]]
| 9300
| 0.89
|-
| Morphine hydrobromide
| [[Schedule II (US)|II]]
| 9300
| 0.78
|-
| Morphine hydrobromide (2 H<sub>2</sub>O)
| [[Schedule II (US)|II]]
| 9300
| 0.71
|-
| Morphine hydrochloride
| [[Schedule II (US)|II]]
| 9300
| 0.89
|-
| Morphine hydrochloride (3 H<sub>2</sub>O)
| [[Schedule II (US)|II]]
| 9300
| 0.76
|-
| Morphine acetate
| [[Schedule II (US)|II]]
| 9300
| 0.71
|-
| Morphine hydriodide (2 H<sub>2</sub>O)
| [[Schedule II (US)|II]]
| 9300
| 0.64
|-
| Morphine lactate
| [[Schedule II (US)|II]]
| 9300
| 0.76
|-
| Morphine monohydrate
| [[Schedule II (US)|II]]
| 9300
| 0.94
|-
| Morphine meconate (5 H<sub>2</sub>O)
| [[Schedule II (US)|II]]
| 9300
| 0.66
|-
| Morphine mucate
| [[Schedule II (US)|II]]
| 9300
| 0.57
|-
| Morphine nitrate
| [[Schedule II (US)|II]]
| 9300
| 0.82
|-
| Morphine phosphate ({{frac|1|2}} H<sub>2</sub>O)
| [[Schedule II (US)|II]]
| 9300
| 0.73
|-
| Morphine phosphate (7 H<sub>2</sub>O)
| [[Schedule II (US)|II]]
| 9300
| 0.73
|-
| Morphine salicylate
| [[Schedule II (US)|II]]
| 9300
|
|-
| Morphine pectinate
| [[Schedule II (US)|II]]
| 9300
| 0.778
|-
| Morphine phenylpropionate
| [[Schedule II (US)|II]]
| 9300
| 0.65
|-
| Morphine methyliodide
| [[Schedule II (US)|II]]
| 9300
| 0.67
|-
| Morphine isobutyrate
| [[Schedule II (US)|II]]
| 9300
| 0.76
|-
| Morphine hypophosphite
| [[Schedule II (US)|II]]
| 9300
| 0.81
|-
| Morphine sulfate (5 H<sub>2</sub>O)
| [[Schedule II (US)|II]]
| 9300
| 0.75
|-
| Morphine tannate
| [[Schedule II (US)|II]]
| 9300
|
|-
| Morphine tartrate (3 H<sub>2</sub>O)
| [[Schedule II (US)|II]]
| 9300
| 0.74
|-
| Morphine valerate
| [[Schedule II (US)|II]]
| 9300
| 0.74
|-
| Morphine diethylbarbiturate
| [[Schedule II (US)|II]]
| 9300
| 0.619
|-
| Morphine cyclopentylallylbarbiturate
| [[Schedule II (US)|II]]
| 9300
| 0.561
|-
| Morphine diacetate
| [[Schedule I (US)|I]]
| 9200
| 0.74
|-
| Morphine methylbromide
| [[Schedule I (US)|I]]
| 9305
| 0.75
|-
| Morphine methylsulfonate
| [[Schedule I (US)|I]]
| 9306
| 0.75
|-
| Morphine-N-oxide
| [[Schedule I (US)|I]]
| 9307
| 1
|-
| Morphine-N-oxide quinate
| [[Schedule I (US)|I]]
| 9307
| 0.60
|-
| Morphine dinicotinate HCl (Nicomorphine)
| [[Schedule I (US)|II]]
| 9312
| 0.931
|-
| Pseudomorphine
| [[Schedule I (US)|I]]
| ''not mentioned''
|}
|}

=== Biosynthesis ===
The morphine is biosynthesized from the tetrahydroisoquinoline [[reticuline]]. It is converted into [[salutaridine]], [[thebaine]], and [[oripavine]]. The enzymes involved in this process are the [[salutaridine synthase]], [[Salutaridine reductase (NADPH)|salutaridine:NADPH 7-oxidoreductase]] and the [[codeinone reductase]].<ref>{{cite journal |vauthors=Novak B, Hudlicky T, Reed J, Mulzer J, Trauner D | title = Morphine Synthesis and Biosynthesis-An Update | journal = Current Organic Chemistry |date=March 2000 | volume = 4 | issue = 3 | pages = 343–362 | doi = 10.2174/1385272003376292 | url = http://brocku.ca/mathematics-science/departments-and-centres/chemistry/faculty/Hudlicky/CurrOrgChem-2000-4-343.pdf }}</ref> Researchers are attempting to reproduce the biosynthetic pathway that produces morphine in [[genetically engineered]] [[yeast]].<ref>{{cite web|url=https://www.newscientist.com/article/dn27546-home-brew-heroin-soon-anyone-will-be-able-to-make-illegal-drugs/|title=Home-brew heroin: soon anyone will be able to make illegal drugs|publisher=New Scientist|author=Michael Le Page|date=18 May 2015}}</ref> In June 2015 the ''S''-reticuline could be produced from sugar and ''R''-reticuline could be converted to morphine, but the intermediate reaction could not be performed.<ref>{{cite web|url=http://news.sciencemag.org/biology/2015/06/final-step-sugar-morphine-conversion-deciphered|title=Final step in sugar-to-morphine conversion deciphered|publisher=Science|author=Robert F. Service|date=25 June 2015}}</ref> In August 2015 the first complete synthesis of thebaine and hydrocodone in yeast were reported, but the process would need to be 100,000 times more productive to be suitable for commercial use.<ref>{{cite journal| journal = Science |date=August 2015 | volume = 349| issue = | pages = 1095–1100| doi =10.1126/science.aac9373| url = http://www.sciencemag.org/content/early/2015/08/12/science.aac9373|vauthors=Galanie S, Thodey K, Trenchard I, Filsinger Interrante M, Smolke C | title =Complete biosynthesis of opioids in yeast}}</ref><ref>{{cite web|title=Yeast-Based Opioid Production Completed|url=http://mobile.the-scientist.com/article/43739/yeast-based-opioid-production-completed|accessdate=15 August 2015|date=13 August 2015}}</ref>

[[File:Morphine biosynthesis.png|center|750px|Morphine biosynthesis]]

=== Synthesis ===
{{Main|Morphine total synthesis}}
The first [[morphine total synthesis]], devised by [[Marshall D. Gates, Jr.]] in 1952, remains a widely used example of [[total synthesis]].<ref>{{cite journal |vauthors=Gates M, Tschudi G |title=The Synthesis of Morphine | journal = Journal of the American Chemical Society |date=April 1956 | volume = 78 | issue = 7 | pages = 1380–1393 | doi = 10.1021/ja01588a033 }}</ref> Several other syntheses were reported, notably by the research groups of Rice,<ref>{{cite journal| author = Rice KC | title = Synthetic opium alkaloids and derivatives. A short total synthesis of (+/-)-dihydrothebainone, (+/-)-dihydrocodeinone, and (+/-)-nordihydrocodeinone as an approach to a practical synthesis of morphine, codeine, and congeners | journal = The Journal of Organic Chemistry |date=July 1980 | volume = 45 | issue = 15 | pages = 3135–3137 | doi = 10.1021/jo01303a045 }}</ref> Evans,<ref>{{cite journal |vauthors=Evans DA, Mitch CH | title = Studies directed towards the total synthesis of morphine alkaloids | journal = Tetrahedron Letters |date=January 1982 | volume = 23 | issue = 3 | pages = 285–288 | doi = 10.1016/S0040-4039(00)86810-0 }}</ref> Fuchs,<ref>{{cite journal |vauthors=Toth JE, Hamann PR, Fuchs PL | title = Studies culminating in the total synthesis of (dl)-morphine | journal = The Journal of Organic Chemistry |date=September 1988 | volume = 53 | issue = 20 | pages = 4694–4708 | doi = 10.1021/jo00255a008 }}</ref> Parker,<ref>{{cite journal |vauthors=Parker KA, Fokas D | title = Convergent synthesis of (+/-)-dihydroisocodeine in 11 steps by the tandem radical cyclization strategy. A formal total synthesis of (+/-)-morphine | journal = Journal of the American Chemical Society |date=November 1992 | volume = 114 | issue = 24 | pages = 9688–9689 | doi = 10.1021/ja00050a075 }}</ref> Overman,<ref>{{cite journal |vauthors=Hong CY, Kado N, Overman LE | title = Asymmetric synthesis of either enantiomer of opium alkaloids and morphinans. Total synthesis of (−)- and (+)-dihydrocodeinone and (−)- and (+)-morphine | journal = Journal of the American Chemical Society |date=November 1993 | volume = 115 | issue = 23 | pages = 11028–11029 | doi = 10.1021/ja00076a086 }}</ref> Mulzer-Trauner,<ref>{{cite journal |vauthors=Mulzer J, Dürner G, Trauner D |title=Formal Total Synthesis of(—)-Morphine by Cuprate Conjugate Addition | journal = Angewandte Chemie International Edition in English |date=December 1996 | volume = 35 | issue = 2324 | pages = 2830–2832 | doi = 10.1002/anie.199628301 }}</ref> White,<ref>{{cite journal |vauthors=White JD, Hrnciar P, Stappenbeck F | title = Asymmetric Total Synthesis of (+)-Codeine via Intramolecular Carbenoid Insertion | journal = The Journal of Organic Chemistry |date=October 1999 | volume = 64 | issue = 21 | pages = 7871–7884 | doi = 10.1021/jo990905z }}</ref> Taber,<ref>{{cite journal |vauthors=Taber DF, Neubert TD, Rheingold AL | title = Synthesis of (−)-Morphine|journal=Journal of the American Chemical Society |date=October 2002 | volume = 124 | issue = 42 | pages = 12416–12417 | doi = 10.1021/ja027882h | pmid = 12381175 }}</ref> Trost,<ref>{{cite journal |vauthors=Trost BM, Tang W | title = Enantioselective Synthesis of (−)-Codeine and (−)-Morphine | journal = Journal of the American Chemical Society |date=December 2002 | volume = 124 | issue = 49 | pages = 14542–14543 | doi = 10.1021/ja0283394 | pmid = 12465957 }}</ref> Fukuyama,<ref>{{cite journal |vauthors=Uchida K, Yokoshima S, Kan T, Fukuyama T | title = Total Synthesis of (±)-Morphine | journal = Organic Letters |date=November 2006 | volume = 8 | issue = 23 | pages = 5311–5313 | doi = 10.1021/ol062112m | pmid = 17078705 }}</ref> Guillou,<ref>{{cite journal |vauthors=Varin M, Barré E, Iorga B, Guillou C |title=Diastereoselective Total Synthesis of (±)-Codeine|journal=Chemistry: A European Journal | year = 2008 | volume = 14 | issue = 22 | pages = 6606–6608 | doi = 10.1002/chem.200800744 }}</ref> and Stork.<ref>{{cite journal |vauthors=Stork G, Yamashita A, Adams J, Schulte GR, Chesworth R, Miyazaki Y, Farmer JJ | title = Regiospecific and Stereoselective Syntheses of (±) Morphine, Codeine, and Thebaine via a Highly Stereocontrolled Intramolecular 4 + 2 Cycloaddition Leading to a Phenanthrofuran System|journal=Journal of the American Chemical Society | year = 2009 | volume = 131 | issue = 32| pages = 11402–11406 | doi = 10.1021/ja9038505 | pmid = 19624126 }}</ref> It is "highly unlikely" that a chemical synthesis will ever be able to compete with the cost of producing morphine from the opium poppy.<ref>{{cite web|url=http://pubs.acs.org/cen/coverstory/83/8325/8325morphine.html|title=The Top Pharmaceuticals That Changed The World-Morphine|publisher=Chemical and Engineering News|author=Michael Freemantle|date=2005-06-20}}</ref>

== Production ==
[[File:Alkaloids.png|thumb|First generation production of Alkaloids from licit latex-derived opium]]
In the [[opium poppy]], the alkaloids are bound to [[meconic acid]]. The method is to extract from the crushed plant with diluted sulfuric acid, which is a stronger acid than meconic acid, but not so strong to react with alkaloid molecules. The [[Extraction (chemistry)|extraction]] is performed in many steps (one amount of crushed plant is extracted at least six to ten times, so practically every [[alkaloid]] goes into the solution). From the solution obtained at the last extraction step, the alkaloids are precipitated by either ammonium hydroxide or sodium carbonate. The last step is purifying and separating morphine from other opium alkaloids. The somewhat similar Gregory process was developed in the United Kingdom during the Second World War, which begins with stewing the entire plant, in most cases save the roots and leaves, in plain or mildly acidified water, then proceeding through steps of concentration, extraction, and purification of alkaloids.{{Citation needed|date=January 2014}} Other methods of processing "poppy straw" (i.e., dried pods and stalks) use steam, one or more of several types of alcohol, or other organic solvents.

The poppy straw methods predominate in Continental Europe and the British Commonwealth, with the latex method in most common use in India. The latex method can involve either vertical or horizontal slicing of the unripe pods with a two-to five-bladed knife with a guard developed specifically for this purpose to the depth of a fraction of a millimetre and scoring of the pods can be done up to five times. An alternative latex method sometimes used in China in the past is to cut off the poppy heads, run a large needle through them, and collect the dried latex 24 to 48 hours later.{{Citation needed|date=January 2014}}

In India, opium harvested by licensed poppy farmers is dehydrated to uniform levels of hydration at government processing centers, and then sold to pharmaceutical companies that extract morphine from the opium. However, in Turkey and Tasmania, morphine is obtained by harvesting and processing the fully mature dry seed pods with attached stalks, called ''poppy straw''. In Turkey, a water extraction process is used, while in Tasmania, a solvent extraction process is used.{{Citation needed|date=April 2014}}

Opium poppy contains at least 50 different alkaloids, but most of them are of very low concentration. Morphine is the principal alkaloid in raw opium and constitutes roughly 8–19% of [[opium]] by dry weight (depending on growing conditions).<ref name="Jenkins AJ 2008" /> Some purpose-developed strains of poppy now produce opium that is up to 26% morphine by weight.{{Citation needed|date=January 2014}} A rough rule of thumb to determine the morphine content of pulverised dried poppy straw is to divide the percentage expected for the strain or crop via the latex method by eight or an empirically determined factor, which is often in the range of 5 to 15.{{Citation needed|date=January 2014}} The Norman strain of ''P. Somniferum'', also developed in [[Tasmania]], produces down to 0.04% morphine but with much higher amounts of [[thebaine]] and [[oripavine]], which can be used to synthesise semi-synthetic opioids as well as other drugs like stimulants, emetics, opioid antagonists, anticholinergics, and smooth-muscle agents.{{Citation needed|date=January 2014}}

In the 1950s and 1960s, [[Hungary]] supplied nearly 60% of Europe's total medication-purpose morphine production. To this day, poppy farming is legal in Hungary, but poppy farms are limited by law to {{convert|2|acre|m2}}. It is also legal to sell dried poppy in flower shops for use in floral arrangements.

It was announced in 1973 that a team at the National Institutes of Health in the United States had developed a method for total synthesis of morphine, [[codeine]], and thebaine using coal tar as a starting material. A shortage in codeine-hydrocodone class cough suppressants (all of which can be made from morphine in one or more steps, as well as from codeine or thebaine) was the initial reason for the research.

Most morphine produced for pharmaceutical use around the world is actually converted into codeine as the concentration of the latter in both raw opium and poppy straw is much lower than that of morphine; in most countries, the usage of codeine (both as end-product and precursor) is at least equal or greater than that of morphine on a weight basis.

== Precursor to other opioids ==

=== Pharmaceutical ===
Morphine is a precursor in the manufacture in a large number of opioids such as [[dihydromorphine]], [[hydromorphone]], [[hydrocodone]], and [[oxycodone]] as well as [[codeine]], which itself has a large family of semi-synthetic derivatives. Morphine is commonly treated with [[acetic anhydride]] and ignited to yield heroin.<ref>{{cite book |vauthors=Small LF, Lutz RE | title = Chemistry of the Opium Alkaloids | publisher = U. S. Government Printing Office | location = Washington, D. C. | year = 1932 | pages = 153–154 | asin = B000H4LBY8 }}</ref>
Throughout Europe there is growing acceptance within the medical community of the use of slow release oral morphine as a substitution treatment alternative to methadone and buprenorphine for patients not able to tolerate the side-effects of buprenorphine and methadone. Slow-release oral morphine has been in widespread use for opiate maintenance therapy in Austria, Bulgaria, and Slovakia for many years and it is available on a small scale in many other countries including the UK. The long-acting nature of slow-release morphine mimics that of buprenorphine because the sustained blood levels are relatively flat so there is no "high" per se that a patient would feel but rather a sustained feeling of wellness and avoidance of withdrawal symptoms. For patients sensitive to the side-effects that in part may be a result of the unnatural pharmacological actions of buprenorphine and methadone, slow-release oral morphine formulations offer a promising future for use managing opiate addiction.
The pharmacology of heroin and morphine is identical except the two [[acetyl]] groups increase the [[lipophilicity|lipid solubility]] of the heroin molecule, causing heroin to cross the [[blood–brain barrier]] and enter the [[Human brain|brain]] more rapidly in injection. Once in the brain, these acetyl groups are removed to yield morphine, which causes the subjective effects of heroin. Thus, heroin may be thought of as a more rapidly acting form of morphine.<ref name="Klous 2005">{{cite journal |vauthors=Klous MG, Van den Brink W, Van Ree JM, Beijnen JH | title = Development of pharmaceutical heroin preparations for medical co-prescription to opioid dependent patients | journal = Drug Alcohol Depend | volume = 80 | issue = 3 | pages = 283–95 |date=December 2005 | pmid = 15916865 | doi = 10.1016/j.drugalcdep.2005.04.008 }}</ref>

=== Illicit ===
Illicit morphine is rarely produced from codeine found in over-the-counter cough and pain medicines. This demethylation reaction is often performed using pyridine and hydrochloric acid.<ref>{{cite journal |vauthors=Rapoport H, Lovell CH, Tolbert BM | title = The Preparation of Morphine-N-methyl-C<sup>14</sup> | journal = Journal of the American Chemical Society |date=December 1951 | volume = 73 | issue = 12 | pages = 5900–5900 | doi = 10.1021/ja01156a543 }}</ref>

Another source of illicit morphine comes from the extraction of morphine from extended-release morphine products, such as MS-Contin. Morphine can be extracted from these products with simple extraction techniques to yield a morphine solution that can be injected.<ref>{{cite journal |vauthors=Crews JC, Denson DD |title=Recovery of morphine from a controlled-release preparation. A source of opioid abuse |journal=Cancer |volume=66 |issue=12 |pages=2642–4 |year=1990 |pmid=2249204 |doi=10.1002/1097-0142(19901215)66:12<2642::AID-CNCR2820661229>3.0.CO;2-B}}</ref> As an alternative, the tablets can be crushed and snorted, injected or swallowed, although this provides much less euphoria but retains some of the extended-release effect, and the extended-release property is why MS-Contin is used in some countries alongside [[methadone]], [[dihydrocodeine]], [[buprenorphine]], [[dihydroetorphine]], [[piritramide]], [[Levacetylmethadol|levo-alpha-acetylmethadol]] ([[LAAM]]), and special 24-hour formulations of [[hydromorphone]] for maintenance and detoxification of those physically dependent on opioids.

Another means of using or misusing morphine is to use chemical reactions to turn it into [[heroin]] or another stronger opioid. Morphine can, using a technique reported in New Zealand (where the initial precursor is codeine) and elsewhere known as home-bake, be turned into what is usually a mixture of morphine, heroin, 3-monoacetylmorphine, 6-monoacetylmorphine, and codeine derivatives like acetylcodeine if the process is using morphine made from demethylating codeine.

Since heroin is one of a series of 3,6 diesters of morphine, it is possible to convert morphine to [[nicomorphine]] (Vilan) using nicotinic anhydride, [[dipropanoylmorphine]] with propionic anhydride, dibutanoylmorphine and disalicyloylmorphine with the respective acid anhydrides. Glacial [[acetic acid]] can be used to obtain a mixture high in 6-monoacetylmorphine, [[niacin]] (vitamin B<sub>3</sub>) in some form would be precursor to 6-nicotinylmorphine, salicylic acid may yield the salicyoyl analogue of 6-MAM, and so on.

The clandestine conversion of morphine to ketones of the hydromorphone class or other derivatives like [[dihydromorphine]] (Paramorfan), [[desomorphine]] (Permonid), [[metopon]], etc. and codeine to [[hydrocodone]] (Dicodid), [[dihydrocodeine]] (Paracodin), etc. is more involved, time-consuming, requires lab equipment of various types, and usually requires expensive catalysts and large amounts of morphine at the outset and is less common but still has been discovered by authorities in various ways during the last 20 years or so. Dihydromorphine can be acetylated into another 3,6 morphine diester, namely [[diacetyldihydromorphine]] (Paralaudin), and hydrocodone into [[thebacon]].

== History ==
[[File:Friedrich Wilhelm Adam Sertuerner.jpg|thumb|[[Friedrich Sertürner]]]]

An opium-based elixir has been ascribed to [[Alchemy|alchemists]] of [[Byzantine Empire|Byzantine]] times, but the specific formula was lost during the Ottoman conquest of [[Constantinople]] ([[Istanbul]]).<ref>{{cite journal|vauthors=Ramoutsaki IA, Askitopoulou H, Konsolaki E | title = Pain relief and sedation in Roman Byzantine texts: ''Mandragoras officinarum'', ''Hyoscyamos niger'' and ''Atropa belladonna'' | journal = International Congress Series |date=December 2002 | volume = 1242 | pages = 43–50 | doi = 10.1016/S0531-5131(02)00699-4 }}</ref> Around 1522, [[Paracelsus]] made reference to an opium-based elixir that he called ''laudanum'' from the Latin word ''laudare'', meaning "to praise" He described it as a potent painkiller, but recommended that it be used sparingly. In the late eighteenth century, when the East India Company gained a direct interest in the opium trade through India, another opiate recipe called [[laudanum]] became very popular among physicians and their patients.

Morphine was discovered as the first active alkaloid extracted from the opium poppy plant in December 1804 in [[Paderborn, Germany]], by [[Friedrich Sertürner]].<ref name=Luch2009 /><ref>Friedrich Sertürner (1805) [https://books.google.com/books?id=8A09AAAAcAAJ&pg=PA229#v=onepage&q&f=false (Untitled letter to the editor)], ''Journal der Pharmacie für Aerzte, Apotheker und Chemisten'' (Journal of Pharmacy for Physicians, Apothecaries, and Chemists), '''13''' : 229–243 ; see especially "III. Säure im Opium" (acid in opium), pp. 234–235, and "I. Nachtrag zur Charakteristik der Säure im Opium" (Addendum on the characteristics of the acid in opium), pp. 236–241.</ref> The drug was first marketed to the general public by Sertürner and Company in 1817 as an [[analgesic]], and also as a treatment for opium and alcohol addiction. It was first used as a poison in 1822 when Dr. [[Edme Castaing]] of France was convicted of murdering a patient.<ref>{{cite book|title=Annual Register|date=1824|publisher=J. Dodsley|page=1|url=https://books.google.ca/books?id=UXZdAAAAIAAJ&pg=PT1&hl=en#v=onepage&q=Edme&f=false|accessdate=1 September 2015}}</ref> Commercial production began in Darmstadt, Germany in 1827 by the pharmacy that became the pharmaceutical company Merck, with morphine sales being a large part of their early growth.{{citation needed|date=January 2014}}

Later it was found that morphine was more addictive than either alcohol or opium, and its extensive use during the [[American Civil War]] allegedly resulted in over 400,000<ref>{{cite journal | author = Vassallo SA | title = Lewis H. Wright Memorial Lecture | journal = ASA New Letter |date=July 2004 | volume = 68 | issue = 7 | pages = 9–10 | url = http://www.asahq.org/For-Members/Publications-and-Research/Periodicals/ASA-Newsletter/July-2004-ASA-Newsletter.aspx}}</ref> sufferers from the "soldier's disease" of morphine addiction.<ref name="urlCanadian Government Commission – Opiate Narcotics">{{cite web | url = http://www.druglibrary.org/schaffer/library/studies/ledain/nonmed4.htm | title = Opiate Narcotics | date = | work = The Report of the Canadian Government Commission of Inquiry into the Non-Medical Use of Drugs | publisher = Canadian Government Commission | pages = }}</ref> This idea has been a subject of controversy, as there have been suggestions that such a disease was in fact a fabrication; the first documented use of the phrase "soldier's disease" was in 1915.<ref name="urlMythical Roots of US Drug Policy – Soldiers Disease and Addicts in the Civil War">{{cite web | url = http://www.druglibrary.org/schaffer/history/soldis.htm | title = Mythical Roots of US Drug Policy – Soldier's Disease and Addicts in the Civil War | author = Mandel J | date = | work = | publisher = }}</ref><ref name="urlSoldiers Disease A Historical Hoax?">{{cite web|url=//www.amusingfacts.com/facts/Detail/soldiers-disease-morphine.html |title=Soldiers Disease A Historical Hoax? |year=2006 |work= |publisher=iPromote Media Inc |deadurl=unfit |archiveurl=https://web.archive.org/web/20070927041927/www.amusingfacts.com/facts/Detail/soldiers-disease-morphine.html |archivedate=27 September 2007 }}</ref>

[[Diacetylmorphine]] (better known as [[heroin]]) was synthesized from morphine in 1874 and brought to market by [[Bayer]] in 1898. Heroin is approximately 1.5 to 2 times more potent than morphine weight for weight. Due to the [[lipophilicity|lipid solubility]] of diacetylmorphine, it can cross the [[blood–brain barrier]] faster than morphine, subsequently increasing the reinforcing component of addiction.<ref name="pmid11961074">{{cite journal |vauthors=Winger G, Hursh SR, Casey KL, Woods JH | title = Relative reinforcing strength of three N-methyl-D-aspartate antagonists with different onsets of action | journal = J. Pharmacol. Exp. Ther. | volume = 301 | issue = 2 | pages = 690–7 |date=May 2002 | pmid = 11961074 | doi = 10.1124/jpet.301.2.690 }}</ref> Using a variety of subjective and objective measures, one study estimated the relative potency of heroin to morphine administered intravenously to post-addicts to be 1.80–2.66&nbsp;mg of morphine sulfate to 1&nbsp;mg of diamorphine hydrochloride (heroin).<ref name="martin and fraser">{{cite journal |vauthors=Martin WR, Fraser HF |title=A comparative study of physiological and subjective effects of heroin and morphine administered intravenously in postaddicts |journal=J. Pharmacol. Exp. Ther. |volume=133 |pages=388–99 |year=1961 |pmid=13767429}}</ref>

[[File:MorphineAdvertisement1900 - no watermark.JPG|thumb|Advertisement for curing morphine addiction, ca. 1900<ref>{{cite journal | year = 1900 | title = Morphine Easy Home Cure | journal = Overland Monthly | volume = 35 | issue = 205 | pages = 14 | url = http://quod.lib.umich.edu/m/moajrnl/ahj1472.2-35.205/22:6?page=root;rgn=full+text;size=100;view=image }}</ref>]]
[[File:Morphine Monojet.jpg|thumb|left|An ampoule of morphine with integral needle for immediate use. Also known as a "syrette". From WWII. On display at the [[Army Medical Services Museum]].]]
Morphine became a controlled substance in the [[United States|US]] under the [[Harrison Narcotics Tax Act]] of 1914, and possession without a prescription in the US is a criminal offense.
Morphine was the most commonly abused narcotic analgesic in the world until heroin was synthesized and came into use. In general, until the synthesis of [[dihydromorphine]] (ca. 1900), the dihydromorphinone class of opioids (1920s), and [[oxycodone]] (1916) and similar drugs, there were no other drugs in the same efficacy range as opium, morphine, and heroin, with synthetics still several years away ([[pethidine]] was invented in Germany in 1937) and opioid agonists among the semi-synthetics were analogues and derivatives of codeine such as [[dihydrocodeine]] (Paracodin), [[ethylmorphine]] (Dionine), and [[benzylmorphine]] (Peronine). Even today, morphine is the most sought after prescription narcotic by heroin addicts when heroin is scarce, all other things being equal; local conditions and user preference may cause [[hydromorphone]], [[oxymorphone]], high-dose oxycodone, or [[methadone]] as well as [[dextromoramide]] in specific instances such as 1970s Australia, to top that particular list. The stop-gap drugs used by the largest absolute number of heroin addicts is probably codeine, with significant use also of [[dihydrocodeine]], poppy straw derivatives like poppy pod and poppy seed tea, [[propoxyphene]], and [[tramadol]].

The structural formula of morphine was determined by 1925 by [[Robert Robinson (organic chemist)|Robert Robinson]]. At least three methods of total synthesis of morphine from starting materials such as coal tar and petroleum distillates have been patented, the first of which was announced in 1952, by Dr. [[Marshall D. Gates, Jr.]] at the [[University of Rochester]].<ref name="urlMarshall D. Gates, Chemist to First Synthesize Morphine, Dies : Rochester News">{{cite web | url = http://www.rochester.edu/news/show.php?id=20 | author = Dickman S | title = Marshall D. Gates, Chemist to First Synthesize Morphine, Dies | date = 3 October 2003 | work = Press Release | publisher = University of Rochester }}</ref> Still, the vast majority of morphine is derived from the opium poppy by either the traditional method of gathering latex from the scored, unripe pods of the poppy, or processes using poppy straw, the dried pods and stems of the plant, the most widespread of which was invented in Hungary in 1925 and announced in 1930 by the chemist János Kabay.

In 2003, there was discovery of endogenous morphine occurring naturally in the human body. Thirty years of speculation were made on this subject because there was a receptor that, it appeared, reacted only to morphine: the [[μ-opioid receptor|μ<sub>3</sub>-opioid receptor]] in human tissue.<ref>{{cite journal |vauthors=Zhu W, Cadet P, Baggerman G, Mantione KJ, Stefano GB |title=Human white blood cells synthesize morphine: CYP2D6 modulation |journal=J. Immunol. |volume=175 |issue=11 |pages=7357–62 |year=2005 |pmid=16301642 |doi=10.4049/jimmunol.175.11.7357}}</ref> Human cells that form in reaction to cancerous [[neuroblastoma]] cells have been found to contain trace amounts of endogenous morphine.<ref>{{cite journal |author=Poeaknapo C, Schmidt J, Brandsch M, Dräger B, Zenk MH |title=Endogenous formation of morphine in human cells |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=101 |issue=39 |pages=14091–6 |year=2004 |pmid=15383669 |pmc=521124 |doi=10.1073/pnas.0405430101|bibcode=2004PNAS..10114091P |last2=Schmidt |last3=Brandsch |last4=Dräger |last5=Zenk }}</ref>

== Society and culture ==

=== Legal status ===
* In [[Australia]], morphine is classified as a [[Standard for the Uniform Scheduling of Drugs and Poisons#Schedule 8 Controlled Drug (Possession without authority illegal)|Schedule 8]] drug under the variously titled State and Territory Poisons Acts.
* In [[Canada]], morphine is classified as a [[Schedule I (Canada)|Schedule I]] drug under the [[Controlled Drugs and Substances Act]].
* In [[France]], morphine is in the strictest schedule of controlled substances, based upon the December 1970 French controlled substances law.
* In [[Germany]], morphine is a ''verkehrsfähiges und verschreibungsfähiges Betäubungsmittel'' listed under ''Anlage III'' (the equivalent of CSA Schedule II) of the [[Betäubungsmittelgesetz]].<ref>[http://www.gesetze-im-internet.de/btmg_1981/anlage_iii_61.html Anlage III (zu §&nbsp;1 Abs.&nbsp;1) verkehrsfähige und verschreibungsfähige Betäubungsmittel]</ref>
*: In [[Switzerland]], morphine is similarly scheduled to Germany's legal classification of the drug.
* In [[Japan]], morphine is classified as a narcotic under the [[:ja:麻薬及び向精神薬取締法|Narcotics and Psychotropics Control Act]] ({{lang|ja|麻薬及び向精神薬取締法}}, ''mayaku oyobi kōseishinyaku torishimarihō'').
* In the [[Netherlands]], morphine is classified as a List 1 drug under the [[Opium Law]].
* In the [[United Kingdom]], morphine is listed as a Class A drug under the [[Misuse of Drugs Act 1971]] and a Schedule 2 Controlled Drug under the [[Misuse of Drugs Regulations 2001]].
* In the [[United States]], morphine is classified as a [[Schedule II (US)|Schedule II]] controlled substance under the [[Controlled Substances Act]] with a main [[Administrative Controlled Substances Code Number]] (ACSCN) of ACSCN&nbsp;9300. Morphine pharmaceuticals in the US are subject to annual manufacturing quotas; morphine production for use in extremely dilute formulations and its production as an intermediate, or chemical precursor, for conversion into other drugs is excluded from the US manufacturing quota.<!--The following text needs to be clarified if it is decensored; it's almost incoherent as is:

The morphine for conversion 2013 quota was {{ clarify | date = June 2015 | reason = It isn't clear what the first and second values denote; "kilos" isn't unit of measurement either.| text =103 750 kilos,}} up from {{ clarify | date = June 2015 | reason = It isn't clear what the first and second values denote; "kilos" isn't unit of measurement either.| text =91 250 kilos}} in 2012. The morphine-for-sale quota was unchanged from the prior year at {{ clarify | date = June 2015 | reason = It isn't clear what the first and second values denote; "kilos" isn't unit of measurement either.| text =60 250 kilos.}}
-->
* [[United Nations|Internationally]] (UN), morphine is a Schedule I drug under the [[Single Convention on Narcotic Drugs]].<ref>{{Cite journal
|date=March 2011 | title = List of narcotic drugs under international control |type=PDF | edition = 50th | publisher = International Narcotics Control Board | publication-place = Austria | page=5 | url = http://www.incb.org/documents/Narcotic-Drugs/Yellow_List/NAR_2011_YellowList_50edition_EN.pdf | work = Yellow List }}</ref>

=== Non-medical use ===
[[File:Morphine DOJ.jpg|thumb|Example of different morphine tablets]]

The euphoria, comprehensive alleviation of distress and therefore all aspects of suffering, promotion of sociability and empathy, "body high", and anxiolysis provided by narcotic drugs including the opioids can cause the use of high doses in the absence of pain for a protracted period, which can impart a morbid craving for the drug in the user. Being the prototype of the entire opioid class of drugs means that morphine has properties that may lend it to misuse. Morphine addiction is the model upon which the current perception of addiction is based.{{mcn|date=October 2015}}

Animal and human studies and clinical experience back up the contention that morphine is one of the most euphoric of drugs on earth, and via all but the IV route heroin and morphine cannot be distinguished according to studies because heroin is a prodrug for the delivery of systemic morphine. Chemical changes to the morphine molecule yield other euphorigenics such as [[dihydromorphine]], [[hydromorphone]] (Dilaudid, Hydal), and [[oxymorphone]] (Numorphan, Opana), as well as the latter three's methylated equivalents [[dihydrocodeine]], [[hydrocodone]], and oxycodone, respectively; in addition to heroin, there are [[dipropanoylmorphine]], [[diacetyldihydromorphine]], and other members of the 3,6 morphine diester category like [[nicomorphine]] and other similar semi-synthetic opiates like [[desomorphine]], [[hydromorphinol]], etc. used clinically in many countries of the world but in many cases also produced illicitly in rare instances.{{mcn|date=October 2015}}

In general, non-medical use of morphine entails taking more than prescribed or outside of medical supervision, injecting oral formulations, mixing it with unapproved potentiators such as alcohol, cocaine, and the like, or defeating the extended-release mechanism by chewing the tablets or turning into a powder for snorting or preparing injectables. The latter method can be as time-consuming and involved as traditional methods of smoking opium. This and the fact that the liver destroys a large percentage of the drug on the first pass impacts the demand side of the equation for clandestine re-sellers, as many customers are not needle users and may have been disappointed with ingesting the drug orally. As morphine is generally as hard or harder to divert than [[oxycodone]] in a lot of cases, morphine in any form is uncommon on the street, although ampoules and phials of morphine injection, pure pharmaceutical morphine powder, and soluble multi-purpose tablets are very popular where available.{{mcn|date=October 2015}}

Morphine is also available in a paste that is used in the production of heroin, which can be smoked by itself or turned to a soluble salt and injected; the same goes for the penultimate products of the Kompot (Polish Heroin) and black tar processes. Poppy straw as well as opium can yield morphine of purity levels ranging from poppy tea to near-pharmaceutical-grade morphine by itself or with all of the more than 50 other alkaloids. It also is the active narcotic ingredient in opium and all of its forms, derivatives, and analogues as well as forming from breakdown of heroin and otherwise present in many batches of illicit heroin as the result of incomplete acetylation.{{mcn|date=October 2015}}

=== Slang terms ===
Informal names for morphine include: Cube Juice, Dope, Dreamer, Emsel, First Line, God's Drug, Hard Stuff, Hocus, Hows, Lydia, Lydic, M, Miss Emma, Mister Blue, Monkey, Morf, Morph, Morphide, Morphie, Morpho, Mother, MS, Ms. Emma, Mud, New Jack Swing (if mixed with [[heroin]]), Sister, Tab, Unkie, Unkie White, and Stuff.<ref>{{Cite book|url=https://books.google.com/?id=G7As-qawdzMC&pg=PA95&dq=happy+powder#v=onepage&q=cube%2520juice&f=false|title=The Encyclopedia of Addictive Drugs|last=Miller|first=Richard Lawrence|date=2002-01-01|publisher=[[Greenwood Publishing Group]]|isbn=978-0-313-31807-8|page=306|language=en}}</ref>

MS Contin tablets are known as misties, and the 100&nbsp;mg extended-release tablets as greys and blockbusters. The "[[speedball (drug)|speedball]]" can use morphine as the opioid component, which is combined with cocaine, [[amphetamines]], [[methylphenidate]], or similar drugs. "Blue Velvet" is a combination of morphine with the antihistamine [[tripelennamine]] (Pyrabenzamine, PBZ, Pelamine) taken by injection, or less commonly the mixture when swallowed or used as a retention enema; the name is also known to refer to a combination of tripelennamine and dihydrocodeine or codeine tablets or syrups taken by mouth. "Morphia" is an older official term for morphine also used as a slang term. "Driving Miss Emma" is intravenous administration of morphine. Multi-purpose tablets (readily soluble hypodermic tablets that can also be swallowed or dissolved under the tongue or betwixt the cheek and jaw) are known, as are some brands of hydromorphone, as Shake & Bake or Shake & Shoot.

Morphine can be smoked, especially diacetylmorphine (heroin), the most common method being the "Chasing The Dragon" method. To perform a relatively crude acetylation to turn the morphine into heroin and related drugs immediately prior to use is known as AAing (for Acetic Anhydride) or home-bake, and the output of the procedure also known as home-bake or, Blue Heroin (not to be confused with Blue Magic heroin, or the linctus known as Blue Morphine or Blue Morphone, or the Blue Velvet mixture described above).

=== Trade names ===
Morphine is [[marketing|marketed]] under many different [[brand name]]s in various parts of the world.<ref name="drugs.com-page">drugs.com [http://www.drugs.com/international/morphine.html Drugs.com international listings for Morphine] Page accessed 2 June 2015</ref>

=== Access in developing countries ===
Although morphine is cheap, people in poorer countries often do not have access to it. According to a 2005 estimate by the [[International Narcotics Control Board]], six countries (Australia, Canada, France, Germany, the United Kingdom, and the United States) consume 79% of the world’s morphine. The less affluent countries, accounting for 80% of the world's population, consumed only about 6% of the global morphine supply. Some countries import virtually no morphine, and in others the drug is rarely available even for relieving severe pain while dying.

Experts in pain management attribute the under-distribution of morphine to an unwarranted fear of the drug's potential for addiction and abuse. While morphine is clearly addictive, Western doctors believe it is worthwhile to use the drug and then wean the patient off when the treatment is over.<ref>{{cite news |author = Donald G. McNeil Jr. |title= Drugs Banned, Many of World's Poor Suffer in Pain|url= http://www.nytimes.com/2007/09/10/health/10pain.html?em&ex=1189483200&en=b29a1fe3ba2b3e19&ei=5087%0A|publisher= New York Times|date= 10 September 2007 |accessdate=11 September 2007}}</ref>

== References ==
{{Reflist
| colwidth = 30em
}}

== External links ==
{{Commons category}}
{{Wikinews|2005 Afghan opium harvest begins}}
* [http://druginfo.nlm.nih.gov/drugportal/dpdirect.jsp?name=Morphine U.S. National Library of Medicine: Drug Information Portal – Morphine]
* [http://www.ebi.ac.uk/pdbe-srv/PDBeXplore/ligand/?ligand=MOI Morphine bound to proteins] in the [[Protein Data Bank|PDB]]
* [http://www.periodicvideos.com/videos/mv_morphine.htm Morphine and Heroin] at ''[[The Periodic Table of Videos]]'' (University of Nottingham)
* Video: Intravenous morphine loading [http://vimeo.com/46550319 (Vimeo)] [https://www.youtube.com/watch?v=ZeBYdQUKMlM (YouTube)] – A short education video teaching health professionals the main points about intravenous loading of analgesics, in particular morphine.

{{Components of Opium}}
{{Analgesics}}
{{Euphoriants}}
{{Euphoriants}}
{{Glycinergics}}
{{Glycinergics}}

Revision as of 19:47, 29 August 2016

Morphine
Clinical data
Pronunciation/ˈmɔːrfn/
Trade namesMScontin, Oramorph, Sevredol, and others[1]
AHFS/Drugs.comMonograph
Pregnancy
category
  • AU: C
Dependence
liability
Physical: High
Psychological: Moderate-High
Addiction
liability
High
Routes of
administration
Inhalation (smoking), insufflation (snorting), oral (PO), rectal, subcutaneous (SC), intramuscular (IM), intravenous (IV), epidural, and intrathecal (IT)
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailability20–40% (oral), 36–71% (rectally),[2] 100% (IV/IM)
Protein binding30–40%
MetabolismHepatic 90%
Onset of action5 min (IV), 15 min (IM),[3] 20 min (PO)[4]
Elimination half-life2–3 h
Duration of action3 to 7 hours[5][6]
ExcretionRenal 90%, biliary 10%
Identifiers
  • (4R,4aR,7S,7aR,12bS)-3-methyl-2,3,4,4a,7,7a-hexahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinoline-7,9-diol
CAS Number
  • 57-27-2 checkY
    64-31-3 (neutral sulfate),
    52-26-6 (hydrochloride)
PubChem CID
IUPHAR/BPS
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard100.000.291 Edit this at Wikidata
Chemical and physical data
FormulaC17H19NO3
Molar mass285.34 g/mol g·mol−1
3D model (JSmol)
Solubility in waterHCl & sulf.: 60 mg/mL (20 °C)
  • CN1CC[C@]23C4=C5C=CC(O)=C4O[C@H]2[C@@H](O)C=C[C@H]3[C@H]1C5
  • InChI=1S/C17H19NO3/c1-18-7-6-17-10-3-5-13(20)16(17)21-15-12(19)4-2-9(14(15)17)8-11(10)18/h2-5,10-11,13,16,19-20H,6-8H2,1H3/t10-,11+,13-,16-,17-/m0/s1 checkY
  • Key:BQJCRHHNABKAKU-KBQPJGBKSA-N checkY
  (verify)

Morphine, sold under many trade names,[1] is a pain medication of the opiate type. It acts directly on the central nervous system (CNS) to decrease the feeling of pain. It can be used for both acute pain and chronic pain. Morphine is also frequently used for pain from myocardial infarction and during labour. It can be given by mouth, by injection into a muscle, by injecting under the skin, intravenously, into the space around the spinal cord, or rectally.[5] Maximum effect is around 20 min when given intravenously and 60 min when given by mouth while duration of effect is between three and seven hours.[5][6] Long-acting formulations also exist.[5]

Potentially serious side effects include a decreased respiratory effort and low blood pressure. Morphine has a high potential for addiction and abuse. If the dose is reduced after long-term use, withdrawal may occur. Common side effects include drowsiness, vomiting, and constipation. Caution is advised when used during pregnancy or breast feeding, as morphine will affect the infant.[5]

Morphine was first isolated between 1803 and 1805 by Friedrich Sertürner.[7] This is generally believed to be the first isolation of an active ingredient from a plant.[8] Merck began marketing it commercially in 1827.[7] Morphine was more widely used after the invention of the hypodermic syringe in 1853–1855.[7][9] Sertürner originally named the substance morphium after the Greek god of dreams, Morpheus, for its tendency to cause sleep.[9][10]

The primary source of morphine is isolation from poppy straw of the opium poppy.[11] In 2013, an estimated 523,000 kilograms of morphine were produced.[12] About 45,000 kilograms were used directly for pain, an increase over the last twenty years of four times.[12] Most use for this purpose was in the developed world.[12] About 70% of morphine is used to make other opioids such as hydromorphone, oxycodone and heroin.[12][13][14] It is a Schedule II drug in the United States,[13] Class A in the United Kingdom,[15] and Schedule I in Canada.[16] It is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system.[17]

Medical uses

Pain

Morphine is used primarily to treat both acute and chronic severe pain. It is also used for pain due to myocardial infarction and for labor pains.[18] Its duration of analgesia is about three to seven hours.[5][6]

However, concerns exist that morphine may increase mortality in the setting of non ST elevation myocardial infarction.[19] Morphine has also traditionally been used in the treatment of acute pulmonary edema.[18] A 2006 review, though, found little evidence to support this practice.[20] A 2016 Cochrane review concluded that morphine is effective in relieving cancer pain. Side-effects of nausea and constipation are rarely severe enough to warrant stopping treatment.[21]

Shortness of breath

Immediate-release morphine is beneficial in reducing the symptom of shortness of breath due to both cancer and noncancer causes.[22][23] In the setting of breathlessness at rest or on minimal exertion from conditions such as advanced cancer or end-stage cardiorespiratory diseases, regular, low-dose sustained-release morphine significantly reduces breathlessness safely, with its benefits maintained over time.[24][25]

Opioid use disorder

Morphine is also available as a slow-release formulation for opiate substitution therapy (OST) in Austria, Bulgaria, and Slovenia, for addicts who cannot tolerate either methadone or buprenorphine.[26]

Contraindications

Relative contraindications to morphine include:

Adverse effects

Adverse effects of opioids
Common and short term
Other
A localized reaction to intravenous morphine caused by histamine release in the veins

Constipation

Like loperamide and other opioids, morphine acts on the myenteric plexus in the intestinal tract, reducing gut motility, causing constipation. The gastrointestinal effects of morphine are mediated primarily by μ-opioid receptors in the bowel. By inhibiting gastric emptying and reducing propulsive peristalsis of the intestine, morphine decreases the rate of intestinal transit. Reduction in gut secretion and increased intestinal fluid absorption also contribute to the constipating effect. Opioids also may act on the gut indirectly through tonic gut spasms after inhibition of nitric oxide generation.[29] This effect was shown in animals when a nitric oxide precursor, L-arginine, reversed morphine-induced changes in gut motility.[30]

Hormone imbalance

Clinical studies consistently conclude that morphine, like other opioids, often causes hypogonadism and hormone imbalances in chronic users of both sexes. This side effect is dose-dependent and occurs in both therapeutic and recreational users. Morphine can interfere with menstruation in women by suppressing levels of luteinizing hormone. Many studies suggest the majority (perhaps as much as 90%) of chronic opioid users have opioid-induced hypogonadism. This effect may cause the increased likelihood of osteoporosis and bone fracture observed in chronic morphine users. Studies suggest the effect is temporary. As of 2013, the effect of low-dose or acute use of morphine on the endocrine system is unclear.[31][32]

Effects on human performance

Most reviews conclude that opioids produce minimal impairment of human performance on tests of sensory, motor, or attentional abilities. However, recent studies have been able to show some impairments caused by morphine, which is not surprising, given that morphine is a central nervous system depressant. Morphine has resulted in impaired functioning on critical flicker frequency (a measure of overall CNS arousal) and impaired performance on the Maddox Wing test (a measure of deviation of the visual axes of the eyes). Few studies have investigated the effects of morphine on motor abilities; a high dose of morphine can impair finger tapping and the ability to maintain a low constant level of isometric force (i.e. fine motor control is impaired),[33] though no studies have shown a correlation between morphine and gross motor abilities.

In terms of cognitive abilities, one study has shown that morphine may have a negative impact on anterograde and retrograde memory,[34] but these effects are minimal and transient. Overall, it seems that acute doses of opioids in non-tolerant subjects produce minor effects in some sensory and motor abilities, and perhaps also in attention and cognition. It is likely that the effects of morphine will be more pronounced in opioid-naive subjects than chronic opioid users.

In chronic opioid users, such as those on Chronic Opioid Analgesic Therapy (COAT) for managing severe, chronic pain, behavioural testing has shown normal functioning on perception, cognition, coordination and behaviour in most cases. One recent study[35] analysed COAT patients to determine whether they were able to safely operate a motor vehicle. The findings from this study suggest that stable opioid use does not significantly impair abilities inherent in driving (this includes physical, cognitive and perceptual skills). COAT patients showed rapid completion of tasks that require speed of responding for successful performance (e.g., Rey Complex Figure Test) but made more errors than controls. COAT patients showed no deficits in visual-spatial perception and organization (as shown in the WAIS-R Block Design Test) but did show impaired immediate and short-term visual memory (as shown on the Rey Complex Figure Test – Recall). These patients showed no impairments in higher order cognitive abilities (i.e., Planning). COAT patients appeared to have difficulty following instructions and showed a propensity toward impulsive behaviour, yet this did not reach statistical significance. It is important to note that this study reveals that COAT patients have no domain-specific deficits, which supports the notion that chronic opioid use has minor effects on psychomotor, cognitive, or neuropsychological functioning.

Reinforcement disorders

Addiction

Before the Morphine by Santiago Rusiñol

Morphine is a highly addictive substance. In controlled studies comparing the physiological and subjective effects of heroin and morphine in individuals formerly addicted to opiates, subjects showed no preference for one drug over the other. Equipotent, injected doses had comparable action courses, with no difference in subjects' self-rated feelings of euphoria, ambition, nervousness, relaxation, drowsiness, or sleepiness.[36] Short-term addiction studies by the same researchers demonstrated that tolerance developed at a similar rate to both heroin and morphine. When compared to the opioids hydromorphone, fentanyl, oxycodone, and pethidine/meperidine, former addicts showed a strong preference for heroin and morphine, suggesting that heroin and morphine are particularly susceptible to abuse and addiction. Morphine and heroin were also much more likely to produce euphoria and other positive subjective effects when compared to these other opioids.[36] The choice of heroin and morphine over other opioids by former drug addicts may also be because heroin (also known as morphine diacetate, diamorphine, or diacetyl morphine) is an ester of morphine and a morphine prodrug, essentially meaning they are identical drugs in vivo. Heroin is converted to morphine before binding to the opioid receptors in the brain and spinal cord, where morphine causes the subjective effects, which is what the addicted individuals are seeking.[37]

Tolerance

Several hypotheses are given about how tolerance develops, including opioid receptor phosphorylation (which would change the receptor conformation), functional decoupling of receptors from G-proteins (leading to receptor desensitization),[38] μ-opioid receptor internalization or receptor down-regulation (reducing the number of available receptors for morphine to act on), and upregulation of the cAMP pathway (a counterregulatory mechanism to opioid effects) (For a review of these processes, see Koch and Hollt.[39]) CCK might mediate some counter-regulatory pathways responsible for opioid tolerance. CCK-antagonist drugs, specifically proglumide, have been shown to slow the development of tolerance to morphine.

Dependence and withdrawal

Cessation of dosing with morphine creates the prototypical opioid withdrawal syndrome, which, unlike that of barbiturates, benzodiazepines, alcohol, or sedative-hypnotics, is not fatal by itself in neurologically healthy patients without heart or lung problems.

Acute morphine withdrawal, along with that of any other opioid, proceeds through a number of stages. Other opioids differ in the intensity and length of each, and weak opioids and mixed agonist-antagonists may have acute withdrawal syndromes that do not reach the highest level. As commonly cited[by whom?], they are:

  • Stage I, 6 to 14 hours after last dose: Drug craving, anxiety, irritability, perspiration, and mild to moderate dysphoria [citation needed]
  • Stage II, 14 to 18 hours after last dose: Yawning, heavy perspiration, mild depression, lacrimation, crying, headaches, runny nose, dysphoria, also intensification of the above symptoms, "yen sleep" (a waking trance-like state) [clarification needed]
  • Stage III, 16 to 24 hours after last dose: Rhinorrhea (runny nose) and increase in other of the above, dilated pupils, piloerection (goose bumps – giving the name 'cold turkey'), muscle twitches, hot flashes, cold flashes, aching bones and muscles, loss of appetite, and the beginning of intestinal cramping [citation needed]
  • Stage IV, 24 to 36 hours after last dose: Increase in all of the above including severe cramping and involuntary leg movements ("kicking the habit" also called restless leg syndrome), loose stool, insomnia, elevation of blood pressure, moderate elevation in body temperature, increase in frequency of breathing and tidal volume, tachycardia (elevated pulse), restlessness, nausea [citation needed]
  • Stage V, 36 to 72 hours after last dose: Increase in the above, fetal position, vomiting, free and frequent liquid diarrhea, which sometimes can accelerate the time of passage of food from mouth to out of system, weight loss of 2 to 5 kg per 24 hours, increased white cell count, and other blood changes [citation needed]
  • Stage VI, after completion of above: Recovery of appetite and normal bowel function, beginning of transition to postacute and chronic symptoms that are mainly psychological, but may also include increased sensitivity to pain, hypertension, colitis or other gastrointestinal afflictions related to motility, and problems with weight control in either direction [citation needed]

In advanced stages of withdrawal, ultrasonographic evidence of pancreatitis has been demonstrated in some patients and is presumably attributed to spasm of the pancreatic sphincter of Oddi.[40]

The withdrawal symptoms associated with morphine addiction are usually experienced shortly before the time of the next scheduled dose, sometimes within as early as a few hours (usually 6–12 hours) after the last administration. Early symptoms include watery eyes, insomnia, diarrhea, runny nose, yawning, dysphoria, sweating, and in some cases a strong drug craving. Severe headache, restlessness, irritability, loss of appetite, body aches, severe abdominal pain, nausea and vomiting, tremors, and even stronger and more intense drug craving appear as the syndrome progresses. Severe depression and vomiting are very common. During the acute withdrawal period, systolic and diastolic blood pressures increase, usually beyond premorphine levels, and heart rate increases,[41] which have potential to cause a heart attack, blood clot, or stroke.

Chills or cold flashes with goose bumps ("cold turkey") alternating with flushing (hot flashes), kicking movements of the legs ("kicking the habit"[37]) and excessive sweating are also characteristic symptoms.[42] Severe pains in the bones and muscles of the back and extremities occur, as do muscle spasms. At any point during this process, a suitable narcotic can be administered that will dramatically reverse the withdrawal symptoms. Major withdrawal symptoms peak between 48 and 96 hours after the last dose and subside after about 8 to 12 days. Sudden withdrawal by heavily dependent users who are in poor health is very rarely fatal. Morphine withdrawal is considered less dangerous than alcohol, barbiturate, or benzodiazepine withdrawal.[43][44]

The psychological dependence associated with morphine addiction is complex and protracted. Long after the physical need for morphine has passed, the addict will usually continue to think and talk about the use of morphine (or other drugs) and feel strange or overwhelmed coping with daily activities without being under the influence of morphine. Psychological withdrawal from morphine is usually a very long and painful process.[45][unreliable medical source] Addicts often suffer severe depression, anxiety, insomnia, mood swings, amnesia (forgetfulness), low self-esteem, confusion, paranoia, and other psychological disorders. Without intervention, the syndrome will run its course, and most of the overt physical symptoms will disappear within 7 to 10 days including psychological dependence. A high probability of relapse exists after morphine withdrawal when neither the physical environment nor the behavioral motivators that contributed to the abuse have been altered. Testimony to morphine's addictive and reinforcing nature is its relapse rate. Abusers of morphine (and heroin) have one of the highest relapse rates among all drug users, ranging up to 98% in the estimation of some medical experts.[46]

Overdose

A large overdose can cause asphyxia and death by respiratory depression if the person does not receive medical attention immediately.[47] Overdose treatment includes the administration of naloxone. The latter completely reverses morphine's effects, but may result in immediate onset of withdrawal in opiate-addicted subjects. Multiple doses may be needed.[47]

The minimum lethal dose is 200 mg, but in case of hypersensitivity, 60 mg can bring sudden death. In serious drug dependency (high tolerance), 2000–3000 mg per day can be tolerated.[48]

Pharmacology

Pharmacodynamics

Endogenous opioids include endorphins, enkephalins, dynorphins, and even morphine itself. Morphine appears to mimic endorphins. Endorphins, a contraction of the term endogenous morphines, are responsible for analgesia (reducing pain), causing sleepiness, and feelings of pleasure. They can be released in response to pain, strenuous exercise, orgasm, or excitement.

Morphine is the prototype narcotic drug and is the standard against which all other opioids are tested. It interacts predominantly with the μ–δ-opioid (Mu-Delta) receptor heteromer.[49][50] The μ-binding sites are discretely distributed in the human brain, with high densities in the posterior amygdala, hypothalamus, thalamus, nucleus caudatus, putamen, and certain cortical areas. They are also found on the terminal axons of primary afferents within laminae I and II (substantia gelatinosa) of the spinal cord and in the spinal nucleus of the trigeminal nerve.[51]

Morphine is a phenanthrene opioid receptor agonist – its main effect is binding to and activating the μ-opioid receptors in the central nervous system. In clinical settings, morphine exerts its principal pharmacological effect on the central nervous system and gastrointestinal tract. Its primary actions of therapeutic value are analgesia and sedation. Activation of the μ-opioid receptors is associated with analgesia, sedation, euphoria, physical dependence, and respiratory depression. Morphine is a rapid-acting narcotic, and it is known to bind very strongly to the μ-opioid receptors, and for this reason, it often has a higher incidence of euphoria/dysphoria, respiratory depression, sedation, pruritus, tolerance, and physical and psychological dependence when compared to other opioids at equianalgesic doses. Morphine is also a κ-opioid and δ-opioid receptor agonist, κ-opioid's action is associated with spinal analgesia, miosis (pinpoint pupils) and psychotomimetic effects. δ-Opioid is thought to play a role in analgesia.[51] Although morphine does not bind to the σ-receptor, it has been shown that σ-agonists, such as (+)-pentazocine, inhibit morphine analgesia, and σ-antagonists enhance morphine analgesia,[52] suggesting downstream involvement of the σ-receptor in the actions of morphine.

The effects of morphine can be countered with opioid antagonists such as naloxone and naltrexone; the development of tolerance to morphine may be inhibited by NMDA antagonists such as ketamine or dextromethorphan.[53] The rotation of morphine with chemically dissimilar opioids in the long-term treatment of pain will slow down the growth of tolerance in the longer run, particularly agents known to have significantly incomplete cross-tolerance with morphine such as levorphanol, ketobemidone, piritramide, and methadone and its derivatives; all of these drugs also have NMDA antagonist properties. It is believed that the strong opioid with the most incomplete cross-tolerance with morphine is either methadone or dextromoramide.

Gene expression

Studies have shown that morphine can alter the expression of a number of genes. A single injection of morphine has been shown to alter the expression of two major groups of genes, for proteins involved in mitochondrial respiration and for cytoskeleton-related proteins.[54]

Effects on the immune system

Morphine has long been known to act on receptors expressed on cells of the central nervous system resulting in pain relief and analgesia. In the 1970s and '80s, evidence suggesting that opioid drug addicts show increased risk of infection (such as increased pneumonia, tuberculosis, and HIV/AIDS) led scientists to believe that morphine may also affect the immune system. This possibility increased interest in the effect of chronic morphine use on the immune system.

The first step of determining that morphine may affect the immune system was to establish that the opiate receptors known to be expressed on cells of the central nervous system are also expressed on cells of the immune system. One study successfully showed that dendritic cells, part of the innate immune system, display opiate receptors. Dendritic cells are responsible for producing cytokines, which are the tools for communication in the immune system. This same study showed that dendritic cells chronically treated with morphine during their differentiation produce more interleukin-12 (IL-12), a cytokine responsible for promoting the proliferation, growth, and differentiation of T-cells (another cell of the adaptive immune system) and less interleukin-10 (IL-10), a cytokine responsible for promoting a B-cell immune response (B cells produce antibodies to fight off infection).[55]

This regulation of cytokines appear to occur via the p38 MAPKs (mitogen-activated protein kinase)-dependent pathway. Usually, the p38 within the dendritic cell expresses TLR 4 (toll-like receptor 4), which is activated through the ligand LPS (lipopolysaccharide). This causes the p38 MAPK to be phosphorylated. This phosphorylation activates the p38 MAPK to begin producing IL-10 and IL-12. When the dendritic cells are chronically exposed to morphine during their differentiation process then treated with LPS, the production of cytokines is different. Once treated with morphine, the p38 MAPK does not produce IL-10, instead favoring production of IL-12. The exact mechanism through which the production of one cytokine is increased in favor over another is not known. Most likely, the morphine causes increased phosphorylation of the p38 MAPK. Transcriptional level interactions between IL-10 and IL-12 may further increase the production of IL-12 once IL-10 is not being produced. This increased production of IL-12 causes increased T-cell immune response.

Further studies on the effects of morphine on the immune system have shown that morphine influences the production of neutrophils and other cytokines. Since cytokines are produced as part of the immediate immunological response (inflammation), it has been suggested that they may also influence pain. In this way, cytokines may be a logical target for analgesic development. Recently, one study has used an animal model (hind-paw incision) to observe the effects of morphine administration on the acute immunological response. Following hind-paw incision, pain thresholds and cytokine production were measured. Normally, cytokine production in and around the wounded area increases in order to fight infection and control healing (and, possibly, to control pain), but pre-incisional morphine administration (0.1–10.0 mg/kg) reduced the number of cytokines found around the wound in a dose-dependent manner. The authors suggest that morphine administration in the acute post-injury period may reduce resistance to infection and may impair the healing of the wound.[56]

Pharmacokinetics

Absorption and metabolism

Morphine can be taken orally, sublingually, bucally, rectally, subcutaneously, intranasally, intravenously, intrathecally or epidurally and inhaled via a nebulizer. On the streets, it is becoming more common to inhale ("Chasing the Dragon"), but, for medical purposes, intravenous (IV) injection is the most common method of administration. Morphine is subject to extensive first-pass metabolism (a large proportion is broken down in the liver), so, if taken orally, only 40–50% of the dose reaches the central nervous system. Resultant plasma levels after subcutaneous (SC), intramuscular (IM), and IV injection are all comparable. After IM or SC injections, morphine plasma levels peak in approximately 20 minutes, and, after oral administration, levels peak in approximately 30 minutes.[57] Morphine is metabolised primarily in the liver and approximately 87% of a dose of morphine is excreted in the urine within 72 hours of administration. Morphine is metabolized primarily into morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G)[58] via glucuronidation by phase II metabolism enzyme UDP-glucuronosyl transferase-2B7 (UGT2B7). About 60% of morphine is converted to M3G, and 6–10% is converted to M6G.[59] Not only does the metabolism occur in the liver but it may also take place in the brain and the kidneys. M3G does not undergo opioid receptor binding and has no analgesic effect. M6G binds to μ-receptors and is half as potent an analgesic as morphine in humans.[59] Morphine may also be metabolized into small amounts of normorphine, codeine, and hydromorphone. Metabolism rate is determined by gender, age, diet, genetic makeup, disease state (if any), and use of other medications. The elimination half-life of morphine is approximately 120 minutes, though there may be slight differences between men and women. Morphine can be stored in fat, and, thus, can be detectable even after death. Morphine can cross the blood–brain barrier, but, because of poor lipid solubility, protein binding, rapid conjugation with glucuronic acid and ionization, it does not cross easily. Diacetylmorphine, which is derived from morphine, crosses the blood–brain barrier more easily, making it more potent.[60]

Extended-release

There are extended-release formulations of orally administered morphine whose effect last longer, which can be given once per day. Brand names for this formulation of morphine include Avinza,[61] Kadian,[61] MS Contin[61] and Dolcontin.[62] For constant pain, the relieving effect of extended-release morphine given once (for Kadian)[63] or twice (for MS Contin)[63] every 24 hours is roughly the same as multiple administrations of immediate release (or "regular") morphine.[64] Extended-release morphine can be administered together with "rescue doses" of immediate-release morphine as needed in case of breakthrough pain, each generally consisting of 5% to 15% of the 24-hour extended-release dosage.[64]

Detection in body fluids

Morphine and its major metabolites, morphine-3-glucuronide and morphine-6-glucuronide, can be detected in blood, plasma, hair, and urine using an immunoassay. Chromatography can be used to test for each of these substances individually. Some testing procedures hydrolyze metabolic products into morphine before the immunoassay, which must be considered when comparing morphine levels in separately published results. Morphine can also be isolated from whole blood samples by solid phase extraction (SPE) and detected using liquid chromatography-mass spectrometry (LC-MS).

Ingestion of codeine or food containing poppy seeds can cause false positives.[65]

A 1999 review estimated that relatively low doses of heroin (which metabolizes immediately into morphine) are detectable by standard urine tests for 1-1.5 days after use.[66] A 2009 review determined that, when the analyte is morphine and the limit of detection is 1 ng/ml, a 20 mg intravenous (IV) dose of morphine is detectable for 12–24 hours. A limit of detection of 0.6 ng/ml had similar results.[67]

Natural occurrence

A freshly-scored opium poppy seedpod bleeding latex.

Morphine is the most abundant opiate found in opium, the dried latex extracted by shallowly scoring the unripe seedpods of the Papaver somniferum poppy. Morphine is generally 8–14% of the dry weight of opium,[68] although specially bred cultivars reach 26% or produce little morphine at all (under 1%, perhaps down to 0.04%). The latter varieties, including the 'Przemko' and 'Norman' cultivars of the opium poppy, are used to produce two other alkaloids, thebaine and oripavine, which are used in the manufacture of semi-synthetic and synthetic opioids like oxycodone and etorphine and some other types of drugs. P. bracteatum does not contain morphine or codeine, or other narcotic phenanthrene-type, alkaloids. This species is rather a source of thebaine.[69] Occurrence of morphine in other Papaverales and Papaveraceae, as well as in some species of hops and mulberry trees has not been confirmed. Morphine is produced most predominantly early in the life cycle of the plant. Past the optimum point for extraction, various processes in the plant produce codeine, thebaine, and in some cases negligible amounts of hydromorphone, dihydromorphine, dihydrocodeine, tetrahydro-thebaine, and hydrocodone (these compounds are rather synthesized from thebaine and oripavine). The human body produces endorphins,[70] which are endogenous opioid peptides that function as neurotransmitters and have similar effects.[71]

Physical and chemical properties

Chemical structure of morphine. The benzylisoquinoline backbone is shown in green.
Same structure with correct 3D configuration; backbone in blue.

Morphine is a benzylisoquinoline alkaloid with two additional ring closures. It has:

Most of the licit morphine produced is used to make codeine by methylation. It is also a precursor for many drugs including heroin (3,6-diacetylmorphine), hydromorphone (dihydromorphinone), and oxymorphone (14-hydroxydihydromorphinone); many morphine derivatives can also be manufactured using thebaine or codeine as a starting material. Replacement of the N-methyl group of morphine with an N-phenylethyl group results in a product that is 18 times more powerful than morphine in its opiate agonist potency. Combining this modification with the replacement of the 6-hydroxyl with a 6-methylene group produces a compound some 1,443 times more potent than morphine, stronger than the Bentley compounds such as etorphine (M99, the Immobilon tranquilliser dart) by some measures.

The structure-activity relationship of morphine has been extensively studied. As a result of the extensive study and use of this molecule, more than 250 morphine derivatives (also counting codeine and related drugs) have been developed since the last quarter of the 19th century. These drugs range from 25% the analgesic strength of codeine (or slightly more than 2% of the strength of morphine) to several thousand times the strength of morphine, to powerful opioid antagonists, including naloxone (Narcan), naltrexone (Trexan), diprenorphine (M5050, the reversing agent for the Immobilon dart) and nalorphine (Nalline). Some opioid agonist-antagonists, partial agonists, and inverse agonists are also derived from morphine. The receptor-activation profile of the semi-synthetic morphine derivatives varies widely and some, like apomorphine are devoid of narcotic effects.

Morphine and most of its derivatives do not exhibit optical isomerism, although some more distant relatives like the morphinan series (levorphanol, dextorphan and the racemic parent chemical dromoran) do, and as noted above stereoselectivity in vivo is an important issue.

Morphine-derived agonist–antagonist drugs have also been developed. Elements of the morphine structure have been used to create completely synthetic drugs such as the morphinan family (levorphanol, dextromethorphan and others) and other groups that have many members with morphine-like qualities. The modification of morphine and the aforementioned synthetics has also given rise to non-narcotic drugs with other uses such as emetics, stimulants, antitussives, anticholinergics, muscle relaxants, local anaesthetics, general anaesthetics, and others.

Most semi-synthetic opioids, both of the morphine and codeine subgroups, are created by modifying one or more of the following:

  • Halogenating or making other modifications at positions 1 or 2 on the morphine carbon skeleton.
  • The methyl group that makes morphine into codeine can be removed or added back, or replaced with another functional group like ethyl and others to make codeine analogues of morphine-derived drugs and vice versa. Codeine analogues of morphine-based drugs often serve as prodrugs of the stronger drug, as in codeine and morphine, hydrocodone and hydromorphone, oxycodone and oxymorphone, nicocodeine and nicomorphine, dihydrocodeine and dihydromorphine, etc.
  • Saturating, opening, or other changes to the bond between positions 7 and 8, as well as adding, removing, or modifying functional groups to these positions; saturating, reducing, eliminating, or otherwise modifying the 7–8 bond and attaching a functional group at 14 yields hydromorphinol; the oxidation of the hydroxyl group to a carbonyl and changing the 7–8 bond to single from double changes codeine into oxycodone.
  • Attachment, removal or modification of functional groups to positions 3 or 6 (dihydrocodeine and related, hydrocodone, nicomorphine); in the case of moving the methyl functional group from position 3 to 6, codeine becomes heterocodeine, which is 72 times stronger, and therefore six times stronger than morphine
  • Attachment of functional groups or other modification at position 14 (oxymorphone, oxycodone, naloxone)
  • Modifications at positions 2, 4, 5 or 17, usually along with other changes to the molecule elsewhere on the morphine skeleton. Often this is done with drugs produced by catalytic reduction, hydrogenation, oxidation, or the like, producing strong derivatives of morphine and codeine.
Structure and properties
Molar mass[73] 285.338 g/mol
Index of refraction, nD ?
Acidity (pKa)[73]
Step 1: 8.21 at 25 °C
Step 2: 9.85 at 20 °C
Solubility[73] 0.15 g/L at 20 °C
Melting point[73] 255 °C
Boiling point[73] 190 °C sublimes

Both morphine and its hydrated form, C17H19NO3H2O, are sparingly soluble in water. In five liters of water, only one gram of the hydrate will dissolve. For this reason, pharmaceutical companies produce sulfate and hydrochloride salts of the drug, both of which are over 300 times more water-soluble than their parent molecule. Whereas the pH of a saturated morphine hydrate solution is 8.5, the salts are acidic. Since they derive from a strong acid but weak base, they are both at about pH = 5; as a consequence, the morphine salts are mixed with small amounts of NaOH to make them suitable for injection.[74]

A number of salts of morphine are used, with the most common in current clinical use being the hydrochloride, sulfate, tartrate, and citrate; less commonly methobromide, hydrobromide, hydroiodide, lactate, chloride, and bitartrate and the others listed below. Morphine diacetate, which is another name for heroin, is a Schedule I controlled substance, so it is not used clinically in the United States; it is a sanctioned medication in the United Kingdom and in Canada and some countries in Continental Europe, its use being particularly common (nearly to the degree of the hydrochloride salt) in the United Kingdom. Morphine meconate is a major form of the alkaloid in the poppy, as is morphine pectinate, nitrate, sulphate, and some others. Like codeine, dihydrocodeine and other (especially older) opiates, morphine has been used as the salicylate salt by some suppliers and can be easily compounded, imparting the therapeutic advantage of both the opioid and the NSAID; multiple barbiturate salts of morphine were also used in the past, as was/is morphine valerate, the salt of the acid being the active principle of valerian. Calcium morphenate is the intermediate in various latex and poppy-straw methods of morphine production, more rarely sodium morphenate takes its place. Morphine ascorbate and other salts such as the tannate, citrate, and acetate, phosphate, valerate and others may be present in poppy tea depending on the method of preparation. Morphine valerate produced industrially was one ingredient of a medication available for both oral and parenteral administration popular many years ago in Europe and elsewhere called Trivalin (not to be confused with the current, unrelated herbal preparation of the same name), which also included the valerates of caffeine and cocaine, with a version containing codeine valerate as a fourth ingredient being distributed under the name Tetravalin.

Closely related to morphine are the opioids morphine-N-oxide (genomorphine), which is a pharmaceutical that is no longer in common use; and pseudomorphine, an alkaloid that exists in opium, form as degradation products of morphine.

The salts listed by the United States Drug Enforcement Administration for reporting purposes, in addition to a few others, are as follows:

Biosynthesis

The morphine is biosynthesized from the tetrahydroisoquinoline reticuline. It is converted into salutaridine, thebaine, and oripavine. The enzymes involved in this process are the salutaridine synthase, salutaridine:NADPH 7-oxidoreductase and the codeinone reductase.[75] Researchers are attempting to reproduce the biosynthetic pathway that produces morphine in genetically engineered yeast.[76] In June 2015 the S-reticuline could be produced from sugar and R-reticuline could be converted to morphine, but the intermediate reaction could not be performed.[77] In August 2015 the first complete synthesis of thebaine and hydrocodone in yeast were reported, but the process would need to be 100,000 times more productive to be suitable for commercial use.[78][79]

Morphine biosynthesis
Morphine biosynthesis

Synthesis

The first morphine total synthesis, devised by Marshall D. Gates, Jr. in 1952, remains a widely used example of total synthesis.[80] Several other syntheses were reported, notably by the research groups of Rice,[81] Evans,[82] Fuchs,[83] Parker,[84] Overman,[85] Mulzer-Trauner,[86] White,[87] Taber,[88] Trost,[89] Fukuyama,[90] Guillou,[91] and Stork.[92] It is "highly unlikely" that a chemical synthesis will ever be able to compete with the cost of producing morphine from the opium poppy.[93]

Production

First generation production of Alkaloids from licit latex-derived opium

In the opium poppy, the alkaloids are bound to meconic acid. The method is to extract from the crushed plant with diluted sulfuric acid, which is a stronger acid than meconic acid, but not so strong to react with alkaloid molecules. The extraction is performed in many steps (one amount of crushed plant is extracted at least six to ten times, so practically every alkaloid goes into the solution). From the solution obtained at the last extraction step, the alkaloids are precipitated by either ammonium hydroxide or sodium carbonate. The last step is purifying and separating morphine from other opium alkaloids. The somewhat similar Gregory process was developed in the United Kingdom during the Second World War, which begins with stewing the entire plant, in most cases save the roots and leaves, in plain or mildly acidified water, then proceeding through steps of concentration, extraction, and purification of alkaloids.[citation needed] Other methods of processing "poppy straw" (i.e., dried pods and stalks) use steam, one or more of several types of alcohol, or other organic solvents.

The poppy straw methods predominate in Continental Europe and the British Commonwealth, with the latex method in most common use in India. The latex method can involve either vertical or horizontal slicing of the unripe pods with a two-to five-bladed knife with a guard developed specifically for this purpose to the depth of a fraction of a millimetre and scoring of the pods can be done up to five times. An alternative latex method sometimes used in China in the past is to cut off the poppy heads, run a large needle through them, and collect the dried latex 24 to 48 hours later.[citation needed]

In India, opium harvested by licensed poppy farmers is dehydrated to uniform levels of hydration at government processing centers, and then sold to pharmaceutical companies that extract morphine from the opium. However, in Turkey and Tasmania, morphine is obtained by harvesting and processing the fully mature dry seed pods with attached stalks, called poppy straw. In Turkey, a water extraction process is used, while in Tasmania, a solvent extraction process is used.[citation needed]

Opium poppy contains at least 50 different alkaloids, but most of them are of very low concentration. Morphine is the principal alkaloid in raw opium and constitutes roughly 8–19% of opium by dry weight (depending on growing conditions).[60] Some purpose-developed strains of poppy now produce opium that is up to 26% morphine by weight.[citation needed] A rough rule of thumb to determine the morphine content of pulverised dried poppy straw is to divide the percentage expected for the strain or crop via the latex method by eight or an empirically determined factor, which is often in the range of 5 to 15.[citation needed] The Norman strain of P. Somniferum, also developed in Tasmania, produces down to 0.04% morphine but with much higher amounts of thebaine and oripavine, which can be used to synthesise semi-synthetic opioids as well as other drugs like stimulants, emetics, opioid antagonists, anticholinergics, and smooth-muscle agents.[citation needed]

In the 1950s and 1960s, Hungary supplied nearly 60% of Europe's total medication-purpose morphine production. To this day, poppy farming is legal in Hungary, but poppy farms are limited by law to 2 acres (8,100 m2). It is also legal to sell dried poppy in flower shops for use in floral arrangements.

It was announced in 1973 that a team at the National Institutes of Health in the United States had developed a method for total synthesis of morphine, codeine, and thebaine using coal tar as a starting material. A shortage in codeine-hydrocodone class cough suppressants (all of which can be made from morphine in one or more steps, as well as from codeine or thebaine) was the initial reason for the research.

Most morphine produced for pharmaceutical use around the world is actually converted into codeine as the concentration of the latter in both raw opium and poppy straw is much lower than that of morphine; in most countries, the usage of codeine (both as end-product and precursor) is at least equal or greater than that of morphine on a weight basis.

Precursor to other opioids

Pharmaceutical

Morphine is a precursor in the manufacture in a large number of opioids such as dihydromorphine, hydromorphone, hydrocodone, and oxycodone as well as codeine, which itself has a large family of semi-synthetic derivatives. Morphine is commonly treated with acetic anhydride and ignited to yield heroin.[94] Throughout Europe there is growing acceptance within the medical community of the use of slow release oral morphine as a substitution treatment alternative to methadone and buprenorphine for patients not able to tolerate the side-effects of buprenorphine and methadone. Slow-release oral morphine has been in widespread use for opiate maintenance therapy in Austria, Bulgaria, and Slovakia for many years and it is available on a small scale in many other countries including the UK. The long-acting nature of slow-release morphine mimics that of buprenorphine because the sustained blood levels are relatively flat so there is no "high" per se that a patient would feel but rather a sustained feeling of wellness and avoidance of withdrawal symptoms. For patients sensitive to the side-effects that in part may be a result of the unnatural pharmacological actions of buprenorphine and methadone, slow-release oral morphine formulations offer a promising future for use managing opiate addiction. The pharmacology of heroin and morphine is identical except the two acetyl groups increase the lipid solubility of the heroin molecule, causing heroin to cross the blood–brain barrier and enter the brain more rapidly in injection. Once in the brain, these acetyl groups are removed to yield morphine, which causes the subjective effects of heroin. Thus, heroin may be thought of as a more rapidly acting form of morphine.[95]

Illicit

Illicit morphine is rarely produced from codeine found in over-the-counter cough and pain medicines. This demethylation reaction is often performed using pyridine and hydrochloric acid.[96]

Another source of illicit morphine comes from the extraction of morphine from extended-release morphine products, such as MS-Contin. Morphine can be extracted from these products with simple extraction techniques to yield a morphine solution that can be injected.[97] As an alternative, the tablets can be crushed and snorted, injected or swallowed, although this provides much less euphoria but retains some of the extended-release effect, and the extended-release property is why MS-Contin is used in some countries alongside methadone, dihydrocodeine, buprenorphine, dihydroetorphine, piritramide, levo-alpha-acetylmethadol (LAAM), and special 24-hour formulations of hydromorphone for maintenance and detoxification of those physically dependent on opioids.

Another means of using or misusing morphine is to use chemical reactions to turn it into heroin or another stronger opioid. Morphine can, using a technique reported in New Zealand (where the initial precursor is codeine) and elsewhere known as home-bake, be turned into what is usually a mixture of morphine, heroin, 3-monoacetylmorphine, 6-monoacetylmorphine, and codeine derivatives like acetylcodeine if the process is using morphine made from demethylating codeine.

Since heroin is one of a series of 3,6 diesters of morphine, it is possible to convert morphine to nicomorphine (Vilan) using nicotinic anhydride, dipropanoylmorphine with propionic anhydride, dibutanoylmorphine and disalicyloylmorphine with the respective acid anhydrides. Glacial acetic acid can be used to obtain a mixture high in 6-monoacetylmorphine, niacin (vitamin B3) in some form would be precursor to 6-nicotinylmorphine, salicylic acid may yield the salicyoyl analogue of 6-MAM, and so on.

The clandestine conversion of morphine to ketones of the hydromorphone class or other derivatives like dihydromorphine (Paramorfan), desomorphine (Permonid), metopon, etc. and codeine to hydrocodone (Dicodid), dihydrocodeine (Paracodin), etc. is more involved, time-consuming, requires lab equipment of various types, and usually requires expensive catalysts and large amounts of morphine at the outset and is less common but still has been discovered by authorities in various ways during the last 20 years or so. Dihydromorphine can be acetylated into another 3,6 morphine diester, namely diacetyldihydromorphine (Paralaudin), and hydrocodone into thebacon.

History

Friedrich Sertürner

An opium-based elixir has been ascribed to alchemists of Byzantine times, but the specific formula was lost during the Ottoman conquest of Constantinople (Istanbul).[98] Around 1522, Paracelsus made reference to an opium-based elixir that he called laudanum from the Latin word laudare, meaning "to praise" He described it as a potent painkiller, but recommended that it be used sparingly. In the late eighteenth century, when the East India Company gained a direct interest in the opium trade through India, another opiate recipe called laudanum became very popular among physicians and their patients.

Morphine was discovered as the first active alkaloid extracted from the opium poppy plant in December 1804 in Paderborn, Germany, by Friedrich Sertürner.[8][99] The drug was first marketed to the general public by Sertürner and Company in 1817 as an analgesic, and also as a treatment for opium and alcohol addiction. It was first used as a poison in 1822 when Dr. Edme Castaing of France was convicted of murdering a patient.[100] Commercial production began in Darmstadt, Germany in 1827 by the pharmacy that became the pharmaceutical company Merck, with morphine sales being a large part of their early growth.[citation needed]

Later it was found that morphine was more addictive than either alcohol or opium, and its extensive use during the American Civil War allegedly resulted in over 400,000[101] sufferers from the "soldier's disease" of morphine addiction.[102] This idea has been a subject of controversy, as there have been suggestions that such a disease was in fact a fabrication; the first documented use of the phrase "soldier's disease" was in 1915.[103][104]

Diacetylmorphine (better known as heroin) was synthesized from morphine in 1874 and brought to market by Bayer in 1898. Heroin is approximately 1.5 to 2 times more potent than morphine weight for weight. Due to the lipid solubility of diacetylmorphine, it can cross the blood–brain barrier faster than morphine, subsequently increasing the reinforcing component of addiction.[105] Using a variety of subjective and objective measures, one study estimated the relative potency of heroin to morphine administered intravenously to post-addicts to be 1.80–2.66 mg of morphine sulfate to 1 mg of diamorphine hydrochloride (heroin).[36]

Advertisement for curing morphine addiction, ca. 1900[106]
An ampoule of morphine with integral needle for immediate use. Also known as a "syrette". From WWII. On display at the Army Medical Services Museum.

Morphine became a controlled substance in the US under the Harrison Narcotics Tax Act of 1914, and possession without a prescription in the US is a criminal offense. Morphine was the most commonly abused narcotic analgesic in the world until heroin was synthesized and came into use. In general, until the synthesis of dihydromorphine (ca. 1900), the dihydromorphinone class of opioids (1920s), and oxycodone (1916) and similar drugs, there were no other drugs in the same efficacy range as opium, morphine, and heroin, with synthetics still several years away (pethidine was invented in Germany in 1937) and opioid agonists among the semi-synthetics were analogues and derivatives of codeine such as dihydrocodeine (Paracodin), ethylmorphine (Dionine), and benzylmorphine (Peronine). Even today, morphine is the most sought after prescription narcotic by heroin addicts when heroin is scarce, all other things being equal; local conditions and user preference may cause hydromorphone, oxymorphone, high-dose oxycodone, or methadone as well as dextromoramide in specific instances such as 1970s Australia, to top that particular list. The stop-gap drugs used by the largest absolute number of heroin addicts is probably codeine, with significant use also of dihydrocodeine, poppy straw derivatives like poppy pod and poppy seed tea, propoxyphene, and tramadol.

The structural formula of morphine was determined by 1925 by Robert Robinson. At least three methods of total synthesis of morphine from starting materials such as coal tar and petroleum distillates have been patented, the first of which was announced in 1952, by Dr. Marshall D. Gates, Jr. at the University of Rochester.[107] Still, the vast majority of morphine is derived from the opium poppy by either the traditional method of gathering latex from the scored, unripe pods of the poppy, or processes using poppy straw, the dried pods and stems of the plant, the most widespread of which was invented in Hungary in 1925 and announced in 1930 by the chemist János Kabay.

In 2003, there was discovery of endogenous morphine occurring naturally in the human body. Thirty years of speculation were made on this subject because there was a receptor that, it appeared, reacted only to morphine: the μ3-opioid receptor in human tissue.[108] Human cells that form in reaction to cancerous neuroblastoma cells have been found to contain trace amounts of endogenous morphine.[109]

Society and culture

Non-medical use

Example of different morphine tablets

The euphoria, comprehensive alleviation of distress and therefore all aspects of suffering, promotion of sociability and empathy, "body high", and anxiolysis provided by narcotic drugs including the opioids can cause the use of high doses in the absence of pain for a protracted period, which can impart a morbid craving for the drug in the user. Being the prototype of the entire opioid class of drugs means that morphine has properties that may lend it to misuse. Morphine addiction is the model upon which the current perception of addiction is based.

Animal and human studies and clinical experience back up the contention that morphine is one of the most euphoric of drugs on earth, and via all but the IV route heroin and morphine cannot be distinguished according to studies because heroin is a prodrug for the delivery of systemic morphine. Chemical changes to the morphine molecule yield other euphorigenics such as dihydromorphine, hydromorphone (Dilaudid, Hydal), and oxymorphone (Numorphan, Opana), as well as the latter three's methylated equivalents dihydrocodeine, hydrocodone, and oxycodone, respectively; in addition to heroin, there are dipropanoylmorphine, diacetyldihydromorphine, and other members of the 3,6 morphine diester category like nicomorphine and other similar semi-synthetic opiates like desomorphine, hydromorphinol, etc. used clinically in many countries of the world but in many cases also produced illicitly in rare instances.

In general, non-medical use of morphine entails taking more than prescribed or outside of medical supervision, injecting oral formulations, mixing it with unapproved potentiators such as alcohol, cocaine, and the like, or defeating the extended-release mechanism by chewing the tablets or turning into a powder for snorting or preparing injectables. The latter method can be as time-consuming and involved as traditional methods of smoking opium. This and the fact that the liver destroys a large percentage of the drug on the first pass impacts the demand side of the equation for clandestine re-sellers, as many customers are not needle users and may have been disappointed with ingesting the drug orally. As morphine is generally as hard or harder to divert than oxycodone in a lot of cases, morphine in any form is uncommon on the street, although ampoules and phials of morphine injection, pure pharmaceutical morphine powder, and soluble multi-purpose tablets are very popular where available.

Morphine is also available in a paste that is used in the production of heroin, which can be smoked by itself or turned to a soluble salt and injected; the same goes for the penultimate products of the Kompot (Polish Heroin) and black tar processes. Poppy straw as well as opium can yield morphine of purity levels ranging from poppy tea to near-pharmaceutical-grade morphine by itself or with all of the more than 50 other alkaloids. It also is the active narcotic ingredient in opium and all of its forms, derivatives, and analogues as well as forming from breakdown of heroin and otherwise present in many batches of illicit heroin as the result of incomplete acetylation.

Slang terms

Informal names for morphine include: Cube Juice, Dope, Dreamer, Emsel, First Line, God's Drug, Hard Stuff, Hocus, Hows, Lydia, Lydic, M, Miss Emma, Mister Blue, Monkey, Morf, Morph, Morphide, Morphie, Morpho, Mother, MS, Ms. Emma, Mud, New Jack Swing (if mixed with heroin), Sister, Tab, Unkie, Unkie White, and Stuff.[112]

MS Contin tablets are known as misties, and the 100 mg extended-release tablets as greys and blockbusters. The "speedball" can use morphine as the opioid component, which is combined with cocaine, amphetamines, methylphenidate, or similar drugs. "Blue Velvet" is a combination of morphine with the antihistamine tripelennamine (Pyrabenzamine, PBZ, Pelamine) taken by injection, or less commonly the mixture when swallowed or used as a retention enema; the name is also known to refer to a combination of tripelennamine and dihydrocodeine or codeine tablets or syrups taken by mouth. "Morphia" is an older official term for morphine also used as a slang term. "Driving Miss Emma" is intravenous administration of morphine. Multi-purpose tablets (readily soluble hypodermic tablets that can also be swallowed or dissolved under the tongue or betwixt the cheek and jaw) are known, as are some brands of hydromorphone, as Shake & Bake or Shake & Shoot.

Morphine can be smoked, especially diacetylmorphine (heroin), the most common method being the "Chasing The Dragon" method. To perform a relatively crude acetylation to turn the morphine into heroin and related drugs immediately prior to use is known as AAing (for Acetic Anhydride) or home-bake, and the output of the procedure also known as home-bake or, Blue Heroin (not to be confused with Blue Magic heroin, or the linctus known as Blue Morphine or Blue Morphone, or the Blue Velvet mixture described above).

Trade names

Morphine is marketed under many different brand names in various parts of the world.[1]

Access in developing countries

Although morphine is cheap, people in poorer countries often do not have access to it. According to a 2005 estimate by the International Narcotics Control Board, six countries (Australia, Canada, France, Germany, the United Kingdom, and the United States) consume 79% of the world’s morphine. The less affluent countries, accounting for 80% of the world's population, consumed only about 6% of the global morphine supply. Some countries import virtually no morphine, and in others the drug is rarely available even for relieving severe pain while dying.

Experts in pain management attribute the under-distribution of morphine to an unwarranted fear of the drug's potential for addiction and abuse. While morphine is clearly addictive, Western doctors believe it is worthwhile to use the drug and then wean the patient off when the treatment is over.[113]

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