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==Medical uses==
==Medical uses==
Hydrocodone is used to treat moderate to severe pain and as an [[antitussive]] to treat cough.<ref name="isbn1-4200-5458-9" /> In one study comparing the potency of hydrocodone to that of [[oxycodone]], it was found that it took 50% more hydrocodone to achieve the same degree of miosis (pupillary contraction).<ref>{{cite pmid|19118954}}</ref> The investigators interpreted this to mean that oxycodone is about 50% more potent than hydrocodone, however, in a study of emergency room patients with fractures, it was found that an equal amount of either drug provided about the same degree of pain relief, indicating that there is little practical difference between them when used for that purpose.<ref>{{cite pmid|15805317}}</ref> Some references state that the analgesic action of hydrocodone begins in 20–30 minutes and lasts about 4–8 hours.<ref name="pmid21785485">{{cite pmid|21785485}}</ref> The manufacturer's information says onset of action is about 10–30 minutes and duration is about 4–6 hours.<ref>{{cite web|url=http://www.drugs.com/mmx/vicodin.html |title=Opioid (Narcotic Analgesics and Acetaminophen Systemic ) |accessdate=2014-03-22}}</ref> Recommended dosing interval is 4–6 hours.
Hydrocodone is used to treat moderate to severe pain and as an [[antitussive]] to treat cough.<ref name="isbn1-4200-5458-9" /> In one study comparing the potency of hydrocodone to that of [[oxycodone]], it was found that it took 50% more hydrocodone to achieve the same degree of miosis (pupillary contraction).<ref>{{cite pmid|19118954}}</ref> The investigators interpreted this to mean that oxycodone is about 50% more potent than hydrocodone. However, in a study of emergency room patients with fractures, it was found that an equal amount of either drug provided about the same degree of pain relief, indicating that there is little practical difference between them when used for that purpose.<ref>{{cite pmid|15805317}}</ref> Some references state that the analgesic action of hydrocodone begins in 20–30 minutes and lasts about 4–8 hours.<ref name="pmid21785485">{{cite pmid|21785485}}</ref> The manufacturer's information says onset of action is about 10–30 minutes and duration is about 4–6 hours.<ref>{{cite web|url=http://www.drugs.com/mmx/vicodin.html |title=Opioid (Narcotic Analgesics and Acetaminophen Systemic ) |accessdate=2014-03-22}}</ref> Recommended dosing interval is 4–6 hours.


==Adverse effects==
==Adverse effects==

Revision as of 12:23, 24 May 2014

Not to be confused with Dihydrocodeine.
Hydrocodone
Clinical data
Other namesdihydrocodeinone
AHFS/Drugs.comMicromedex Detailed Consumer Information
MedlinePlusa601006
Dependence
liability		Moderate
Routes of
administration		oral, intranasal, rectal
ATC code
Legal status
Legal status
Pharmacokinetic data
BioavailabilityHigh
MetabolismHepatic
Elimination half-life3.8–6 hours
ExcretionRenal
Identifiers
  • 4,5a-Epoxy-3-methoxy-17-methylmorphinan-6-one
CAS Number
PubChem CID
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard100.004.304 Edit this at Wikidata
Chemical and physical data
FormulaC18H21NO3
Molar mass299.368 g/mol g·mol−1
3D model (JSmol)
  • O=C4[C@@H]5Oc1c2c(ccc1OC)C[C@H]3N(CC[C@]25[C@H]3CC4)C
  • InChI=1S/C18H21NO3/c1-19-8-7-18-11-4-5-13(20)17(18)22-16-14(21-2)6-3-10(15(16)18)9-12(11)19/h3,6,11-12,17H,4-5,7-9H2,1-2H3/t11-,12+,17-,18-/m0/s1 checkY
  • Key:LLPOLZWFYMWNKH-CMKMFDCUSA-N checkY
  (verify)

Hydrocodone is a semi-synthetic opioid derived from codeine. Hydrocodone is used orally as a narcotic analgesic and antitussive (cough medicine), often in combination with paracetamol (acetaminophen) or ibuprofen.[1] Hydrocodone is prescribed predominantly within the United States; elsewhere it is rare. The International Narcotics Control Board reported 99% of the worldwide supply in 2007 was consumed in the United States.[2]

Medical uses

Hydrocodone is used to treat moderate to severe pain and as an antitussive to treat cough.[1] In one study comparing the potency of hydrocodone to that of oxycodone, it was found that it took 50% more hydrocodone to achieve the same degree of miosis (pupillary contraction).[3] The investigators interpreted this to mean that oxycodone is about 50% more potent than hydrocodone. However, in a study of emergency room patients with fractures, it was found that an equal amount of either drug provided about the same degree of pain relief, indicating that there is little practical difference between them when used for that purpose.[4] Some references state that the analgesic action of hydrocodone begins in 20–30 minutes and lasts about 4–8 hours.[5] The manufacturer's information says onset of action is about 10–30 minutes and duration is about 4–6 hours.[6] Recommended dosing interval is 4–6 hours.

Adverse effects

Common side effects of hydrocodone are nausea, vomiting, constipation, drowsiness, dizziness, lightheadedness, fuzzy thinking, anxiety, abnormally happy or sad mood, dry throat, difficulty urinating, rash, itching, and narrowing of the pupils. Serious side effects include slowed or irregular breathing and chest tightness.[7]

Several cases of progressive bilateral hearing loss unresponsive to steroid therapy have been described as an infrequent adverse reaction to hydrocodone/paracetamol misuse. This adverse effect has been considered due to the ototoxicity of hydrocodone.[8][9] Recently, researchers suggested that paracetamol is the primary agent responsible for the ototoxicity.[10][11]

It is in FDA pregnancy category C. No adequate and well-controlled studies in humans have been conducted. A newborn of a mother taking opioid medications regularly prior to the birth will be physically dependent. The baby may also exhibit respiratory depression if the opioid dose was high.[12] An epidemiological study indicated that opioid treatment during early pregnancy results in increased risk of various birth defects.[13]

Symptoms of hydrocodone overdose include narrowed or widened pupils; slow, shallow, or stopped breathing; slowed or stopped heartbeat; cold, clammy, or blue skin; excessive sleepiness; loss of consciousness; seizures; or death.[7]

Hydrocodone can be habit-forming, causing physical and psychological dependence. Its abuse liability is similar to morphine and less than oxycodone.[14]

Contraindications and interactions

Patients consuming alcohol, other opioids, antihistamines, antipsychotics, antianxiety agents, or other central nervous system (CNS) depressants together with hydrocodone may exhibit an additive CNS depression.[12] Hydrocodone may interact with serotonergic medications.[15]

Pharmacology

As a narcotic, hydrocodone relieves pain by binding to opioid receptors in the CNS. It acts primarily on μ-opioid receptors, with about six times lesser affinity to δ-opioid receptors. In blood, 20–50% of hydrocodone is bound to protein.[5][16]

Studies have shown hydrocodone is stronger than codeine but only one-tenth as potent as morphine at binding to receptors and reported to be only 59% as potent as morphine in analgesic properties. However, in tests conducted on rhesus monkeys, the analgesic potency of hydrocodone was actually higher than morphine.[17] Per os hydrocodone has a mean equivalent daily dosage (MEDD) factor of 0.4, meaning that 1 mg of hydrocodone is equivalent to 0.4 mg of intravenous morphine. However, because of morphine's low oral bioavailability, there is a 1:1 correspondence between orally administered morphine and orally administered hydrocodone.[18]

Pharmacokinetics

In the liver, Hydrocodone is transformed into several metabolites. It has a serum half-life that averages 3.8 hours.[17] The hepatic cytochrome P450 enzyme CYP2D6 converts it into hydromorphone, a more potent opioid. However, extensive and poor cytochrome 450 CYP2D6 metabolizers had similar physiological and subjective responses to hydrocodone, and CYP2D6 inhibitor quinidine did not change the responses of extensive metabolizers, suggesting that inhibition of CYP2D6 metabolism of hydrocodone has no practical importance.[19][20] Ultrarapid CYP2D6 metabolizers (1-2% of the population) may have an increased response to hydrocodone; however, hydrocodone metabolism in this population has not been studied.[21]

A major metabolite, norhydrocodone, is predominantly formed by CYP3A4-catalyzed oxidation. Inhibition of CYP3A4 in a child who was, in addition, a poor CYP2D6 metabolizer, resulted in a fatal overdose of hydrocodone.[22] Approximately 40% of hydrocodone metabolism is attributed to non-cytochrome catalyzed reactions.[23]

Formulations

Hydrocodone/paracetamol

Hydrocodone and paracetamol (acetaminophen) 5-500 tablets (Mallinckrodt)
Main article: Hydrocodone/paracetamol

Most hydrocodone is formulated in combination with a second analgesic, such as paracetamol. Examples of hydrocodone-paracetamol combinations include Vicodin and Lortab.

Zohydro

In 2014, the FDA approved prescription-only marketing by Zogenix Pharmaceuticals of the first pure hydrocodone product in the U.S, known by the brand name Zohydro. The drug comes in extended-release capsules with hydrocodone powder inside, in doses of 10 mg, 15 mg, 20 mg, 30 mg, 40 mg and 50 mg. This is 5 times as much active opioid as the highest strength Hydrocodone-APAP product (10 mg/325 mg). Zohydro ER (hydrocodone bitartrate) is indicated for the management of pain severe enough to require daily, around-the-clock, long-term opioid treatment for which alternative treatment options are inadequate. Zohydro is a schedule II controlled substance under the CSA.[24]

The approval of Zohydro was controversial, due to concerns over its potential for substance abuse. The FDA approved Zohydro over the objections of its own review panel, which voted 12 to 2 against approval. The panel stated that if approved, Zohydro would likely "be abused, possibly at a rate greater than that of currently available hydrocodone combination products". 30 U.S. states asked the FDA not to approve Zohydro in capsule form due to its potency and the ease with which it could be abused, by being crushed and then snorted or injected.[25] Zohydro was briefly prohibited in Massachusetts before a federal judge ruled that the state's ban was preempted by the earlier federal approval.[26][27]

Recreational use

Many users of hydrocodone report a sense of satisfaction (euphoria), especially at higher doses. A number of users also report a warm or pleasant numbing sensation throughout the body, one of the best-known effects of narcotics.[28] [medical citation needed] Withdrawal symptoms may include severe pain, pins-and-needles sensations throughout the body, sweating, extreme anxiety and restlessness, sneezing, watery eyes, fever, depression, stomach cramps, diarrhea, and extreme drug cravings. [29][unreliable medical source?]

Taking hydrocodone with grapefruit juice is believed to enhance its narcotic effect. It is hypothesized that the CYP3A4 inhibitors in grapefruit juice may interfere with the metabolism of hydrocodone,[30] although there has been no research into this issue. Additionally, many medications are either substrates (competing for metabolism and exhausting available enzymes) or direct inhibitors of CYP3A4. Inhibition of another enzyme, CYP2D6, would also increase the duration of hydrocodone's elevated concentration in the blood, leading to exaggerated effects. Complete inhibition of both enzymes would theoretically inhibit 60% of the factors involved in hydrocodone metabolism.

Detection in bodily fluids

Hydrocodone concentrations are measured in blood, plasma, and urine to seek evidence of misuse, to confirm diagnoses of poisoning, and to assist in investigations into deaths. Many commercial opiate screening tests react indiscriminately with hydrocodone, other opiates, and their metabolites, but chromatographic techniques can easily distinguish hydrocodone uniquely. Blood and plasma hydrocodone concentrations typically fall in the 5–30 µg/L range among people taking the drug therapeutically, 100–200 µg/L among abusers, and 100–1,600 µg/L in cases of acute, fatal overdosage.[31][32]

Regulation

Australia

In Australia, hydrocodone is a Schedule 8 (S8) or Controlled Drug.

Austria

Hydrocodone is regulated in the same fashion as in Germany (see below) under the Austrian Suchtmittelgesetz; since 2002 it has been available in the form of German products and those produced elsewhere in the European Union under Article 76 of the Schengen Treaty—prior to this, no Austrian companies produced hydrocodone products, with dihydrocodeine and nicomorphine being more commonly used for the same levels of pain and the former for coughing.

Belgium

In Belgium, hydrocodone is no longer available for medical use.

Canada

In Canada, hydrocodone is a controlled substance and is available by prescription only. Hydrocodone is prescribed alone as well as in proprietary combinations, typically with an NSAID or paracetamol,

France

In France, hydrocodone (Vicodin) is no longer available for medical use. Hydrocodone is a prohibited narcotic.

Germany

In Germany, hydrocodone is no longer available for medical use. Hydrocodone is listed under the Betäubungsmittelgesetz as a Suchtgift in the same category as morphine.

Luxembourg

In Luxembourg, hydrocodone is available by prescription under the name Biocodone. Prescriptions are more commonly given for use as a cough suppressant (antitussive) rather than for pain relief (analgesic).

The Netherlands

In the Netherlands, hydrocodone is not available for medical use and is classified as a List 1 drug under the Opium Law.

Sweden

Hydrocodone is no longer available for medical use. The last remaining formula was banned in 1967.

United Kingdom

In the UK, hydrocodone is not available for medical use and is listed as a Class A drug under the Misuse of Drugs Act 1971. Various formulations of dihydrocodeine, a weaker opioid, are frequently used as an alternative for the aforementioned indications of hydrocodone use.

United States

In the U.S., formulations containing more than 15 mg per dosage unit are considered Schedule II drugs, as would any formulation consisting of just hydrocodone alone. Those containing less than or equal to 15 mg per dosage unit in combination with acetaminophen or another non-controlled drug are called hydrocodone compounds and are currently considered Schedule III drugs. Hydrocodone is typically found in combination with other drugs such as acetaminophen, aspirin, ibuprofen and homatropine methylbromide. The purpose of the non-controlled drugs in combination is often twofold: 1) To provide increased analgesia with a synergy from multiple painkillers. 2) To deter the misuse of hydrocodone by causing exaggerated side effects at higher-than-prescribed doses. Hydrocodone is not commercially available in pure form in the United States due to a separate regulation, and is always sold with an NSAID, paracetamol, antihistamine, expectorant, or homatropine. Pure hydrocodone is a more strictly controlled Schedule II drug[33] and sold by compounding pharmacies. The cough preparation Codiclear DH is the purest commercial US hydrocodone item, containing guaifenesin and small amounts of ethanol as active ingredients.

Under the Controlled Substances Act (CSA), hydrocodone is currently listed as both a Schedule II and Schedule III substance depending on the formulation.

  • Schedule II lists hydrocodone in pure form and any formulations of combination products containing more than 15 mg hydrocodone per dosage unit.
  • Schedule III lists hydrocodone in formulations of combination products containing up to 15 mg hydrocodone per dosage unit.

On 25-Oct-2013 the U.S. Food & Drug Administration recommended tighter controls of the drug by reclassifying all formulations of hydrocodone as Schedule II. Critics of hydrocodone use have lobbbied unsuccessfully to reclassify all hydrocodone preparations as Schedule II Controlled Substances, with some seeking reform in 2014.[34] However, there has been pressure from many pharmaceutical firms, medical professionals, and patients, particularly those undergoing pain management, have stressed that reclassification is unnecessary and would be counter-productive to effectively provide pain relief for those suffering. Those opposed to reclassification also maintain that existing protocol for prescribing opioids and the existing inclusion of acetaminophen along with other NSAIDs, are effective measures in deterring misuse.

Hydrocodone was until recently the active antitussive in more than 200 formulations of cough syrups and tablets sold in the United States. In late 2006, the FDA began forcing the recall of many of these formulations due to reports of deaths in infants and children under the age of six. The legal status of drug formulations originally sold between 1938 and 1962—before FDA approval was required—was ambiguous. As a result of FDA enforcement action, by August 2010, 88% of the hydrocodone-containing medications had been removed from the market.[35][failed verification]

At the present time[when?], doctors, pharmacists, and codeine-sensitive or allergic patients or sensitive to the amounts of histamine released by its metabolites must choose among rapidly dwindling supplies of the Hycodan-Codiclear-Hydromet type syrups, Tussionex—an extended-release suspension similar to the European products Codipertussin (codeine hydrochloride), Paracodin suspension (dihydrocodeine hydroiodide), Tusscodin (nicocodeine hydrochloride) and others—and a handful of weak dihydrocodeine syrups. The low sales volume and Schedule II status of Dilaudid cough syrup predictably leads to under-utilisation of the drug. There are several conflicting views concerning the US availability of cough preparations containing ethylmorphine (also called dionine or codethyline)—Feco Syrup and its equivalents were first marketed circa 1895 and still in common use in the 1940s and 1950s, and the main ingredient is treated like codeine under the Controlled Substances Act of 1970.[citation needed]

As of July 2010, the FDA was considering banning some hydrocodone and oxycodone fixed-combination proprietary prescription drugs—based on the paracetamol content and the widespread occurrence of liver damage. FDA action on this suggestion would ostensibly also affect codeine and dihydrocodeine products such as the Tylenol With Codeine and Panlor series of drugs.[citation needed] In 2010, it was the most prescribed drug in the USA, with 131.2 million prescriptions of hydrocodone (combined with paracetamol) being written.[36]

The rationale of combining hydrocodone with other pain-killers is that the combination may increase efficacy, and the adverse effects may be reduced as compared with an equally effective dose of a single agent.[37][38] A combination of hydrocodone and ibuprofen was more effective than either of the drugs on their own in relieving postoperative pain. The overall effect of the combination could be presented as a sum of the effects of ibuprofen and hydrocodone, which is consistent with differing mechanisms of action of these drugs.[39][40][41] Similar results were observed for hydrocodone-acetaminophen combination.[37]

Four pharmaceutical companies (Purdue Pharma, Cephalon, Egalet and Zogenix) are developing extended-release formulations of hydrocodone by itself; the Zogenix product was approved by the US FDA on October 25, 2013 and was launched in the 1st Quarter of the Market in 2014. These formulations were designed to avoid the issue of hepatotoxicity precipitated by acetaminophen. These new extended-release preparations also offer lower abuse potential.[42]

History

Hydrocodone was first synthesized in Germany in 1920 by Carl Mannich and Helene Löwenheim.[43] It was approved by the Food and Drug Administration on 23 March 1943 for sale in the United States and approved by Health Canada for sale in Canada under the brand name Hycodan.[44][45]

See also

References

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  3. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 19118954, please use {{cite journal}} with |pmid=19118954 instead.
  4. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 15805317, please use {{cite journal}} with |pmid=15805317 instead.
  5. ^ a b Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 21785485, please use {{cite journal}} with |pmid=21785485 instead.
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  10. ^ Template:Cite PMID
  11. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 20193831, please use {{cite journal}} with |pmid=20193831 instead.
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  13. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 21345403, please use {{cite journal}} with |pmid=21345403 instead.
  14. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 22992943, please use {{cite journal}} with |pmid=22992943 instead.
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  19. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 9103485, please use {{cite journal}} with |pmid=9103485 instead.
  20. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 16968950, please use {{cite journal}} with |pmid=16968950 instead.
  21. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 22205192, please use {{cite journal}} with |pmid=22205192 instead.
  22. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 20837591, please use {{cite journal}} with |pmid=20837591 instead.
  23. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 23226064, please use {{cite journal}} with |pmid=23226064 instead.
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  30. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 20686478, please use {{cite journal}} with |pmid=20686478 instead.
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  33. ^ "Controlled Substances Act". Wikipedia. Retrieved 8 February 2012.
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  37. ^ a b Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 7192153, please use {{cite journal}} with |pmid=7192153 instead.
  38. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 11493367, please use {{cite journal}} with |pmid=11493367 instead.
  39. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 9951432, please use {{cite journal}} with |pmid=9951432 instead.
  40. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 9505982, please use {{cite journal}} with |pmid=9505982 instead.
  41. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 15295955, please use {{cite journal}} with |pmid=15295955 instead.
  42. ^ Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 23358452, please use {{cite journal}} with |pmid=23358452 instead.
  43. ^ Mannich, C.; Löwenheim, H. (1920). "Ueber zwei neue Reduktionsprodukte des Kodeins". Archiv der Pharmazie. 258 (2–4): 295–316. doi:10.1002/ardp.19202580218.{{cite journal}}: CS1 maint: multiple names: authors list (link)
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  45. ^ "FDA Docket No. 2007N-0353, Drug Products Containing Hydrocodone; Enforcement Action Dates". FDA. Retrieved 7 January 2006. See section I. B., DESI Review of Hydrocodone Products

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