|Systematic (IUPAC) name|
|Legal status||Controlled (S8) (AU) Schedule I (CA) CD (UK) Schedule III (US)|
|Routes||IV, IM, Insufflated, oral, topical|
|Metabolism||Hepatic, primarily by CYP3A4|
|Mol. mass||237.725 g/mol|
|Melt. point||262 °C (504 °F)|
| (what is this?)
Ketamine is a drug used in human and veterinary medicine, primarily for the induction and maintenance of general anesthesia, usually in combination with a sedative. Other uses include sedation in intensive care, analgesia (particularly in emergency medicine), and treatment of bronchospasm. Ketamine has a wide range of effects in humans, including analgesia, anesthesia, hallucinations, elevated blood pressure, and bronchodilation. Like other drugs of its class such as tiletamine and phencyclidine (PCP), it induces a state referred to as "dissociative anesthesia" and is used as a recreational drug.
Ketamine has been shown to be effective in treating depression in patients with bipolar disorder who have not responded to antidepressants. In persons with major depressive disorder, it produces a rapid antidepressant effect, acting within two hours as opposed to the several weeks taken by typical antidepressants to work.
Its hydrochloride salt is sold as Ketanest, Ketaset, and Ketalar. Pharmacologically, ketamine is classified as an NMDA receptor antagonist. At high, fully anesthetic level doses, ketamine has also been found to bind to μ-opioid receptors type 2 in cultured human neuroblastoma cells – however, without agonist activity – and to sigma receptors in rats. Also, ketamine interacts with muscarinic receptors, descending monoaminergic pain pathways and voltage-gated calcium channels.
Ketamine is a chiral compound. Most pharmaceutical preparations of ketamine are racemic; however, some brands reportedly have (mostly undocumented) differences in enantiomeric proportions. The more active enantiomer, (S)-ketamine, is also available for medical use under the brand name Ketanest S.
Medicinal use 
Indications for use as an anaesthetic:
- Pediatric anesthesia (as the sole anesthetic for minor procedures or as an induction agent followed by muscle relaxant and endotracheal intubation);
- Asthmatics or patients with chronic obstructive airway disease;
- As part of a cream, gel, or liquid for topical application for nerve pain — the most common mixture is 10% ketoprofen, 5% lidocaine, and 10% ketamine. Other ingredients found useful by pain specialists and their patients, as well as the compounding pharmacists who make the topical mixtures, include amitriptyline, cyclobenzaprine, clonidine, tramadol, gabapentin, baclofen, and mepivacaine and other longer-acting local anaesthetics (eg. tetracaine, procaine).
- Emergency surgery in field conditions in war zones;
- To supplement spinal/epidural anesthesia/analgesia using low doses;
In medical settings, ketamine is usually injected intravenously or intramuscularly. Since it suppresses breathing much less than most other available anaesthetics, ketamine is still used in human medicine as an anesthetic; however, due to the hallucinations it may cause, it is not typically used as a primary anesthetic, although it is the anaesthetic of choice when reliable ventilation equipment is not available. Ketamine tends to increase heart rate and blood pressure. Because it tends to increase or maintain cardiac output, it is sometimes used in anesthesia for emergency surgery when the patient's fluid volume status is unknown (e.g., from traffic accidents). Ketamine can be used in podiatry and other minor surgery, and occasionally for the treatment of migraine. Research is ongoing in France, the Netherlands, Russia, Australia and the US into the drug's usefulness in pain therapy, depression, and for the treatment of alcoholism and heroin addiction.
In veterinary anesthesia, ketamine is often used for its anesthetic and analgesic effects on cats, dogs, rabbits, rats, and other small animals. Veterinarians often use ketamine with sedative drugs to produce balanced anesthesia and analgesia, and as a constant-rate infusion to help prevent pain wind-up. Ketamine is used to manage pain among large animals, though it has less effect on bovines. It is the primary intravenous anesthetic agent used in equine surgery, often in conjunction with detomidine and thiopental, or sometimes guaifenesin.
Ketamine may be used in small doses (0.1–0.5 mg/kg·h) as a local anesthetic, particularly for the treatment of pain associated with movement and neuropathic pain. It may also be used as an intravenous coanalgesic with opiates to manage otherwise intractable pain, particularly if this pain is neuropathic (pain due to vascular insufficiency or shingles are good examples). It has the added benefit of counteracting spinal sensitization or wind-up phenomena experienced with chronic pain. At these doses, the psychotropic side effects are less apparent and well managed with benzodiazepines. Ketamine is a coanalgesic, so is most effective when used alongside a low-dose opioid; while it does have analgesic effects by itself, the higher doses required can cause disorienting side effects. The combination of ketamine with an opioid is, however, particularly useful for pain caused by cancer.
The effect of ketamine on the respiratory and circulatory systems is different from that of other anesthetics. When used at anesthetic doses, it will usually stimulate rather than depress the circulatory system. It is sometimes possible to perform ketamine anesthesia without protective measures to the airways. Ketamine is also a potent analgesic and can be used in subanesthetic doses to relieve acute pain; however, its psychotropic properties must be taken into account. Patients have reported vivid hallucinations, "going into other worlds" or "seeing God" while anesthetized, and these unwanted psychological side effects have reduced the use of ketamine in human medicine. They can, however, usually be avoided by concomitant application of a sedative such as a benzodiazepine.
Low-dose ketamine is recognized for its potential effectiveness in the treatment of complex regional pain syndrome (CRPS). Although low-dose ketamine therapy is established as a generally safe procedure, reported side effects in some patients have included hallucinations, dizziness, lightheadedness and nausea. Therefore, nurses administering ketamine to patients with CRPS should do so only in a setting where a trained physician is available if needed to assess potential adverse effects on patients.
In some neurological intensive care units, ketamine has been used in cases of prolonged seizures. Some evidence indicates the NMDA-blocking effect of the drug protects neurons from glutamatergic damage during prolonged seizures.
- Pain Management
- The dissociative anesthetic effects of ketamine have also been applied for postoperative pain management. Low doses of ketamine have been found to significantly reduce morphine consumption, as well as reports of nausea following abdominal surgery.
- Oral ketamine
- • Ketamine can be started using the oral route or patients may be changed from a subcutaneous infusion when pain is controlled.
- • Starting dose: 5-10 mg four times daily
- • Increase dose in 5-10 mg increments
- • Usual dose range: 10-60 mg four times daily
- Subcutaneous ketamine infusion
- • Starting dose: 50-150 mg/24 hours
- • Review daily, increase dose in 50-100 mg increments
- • Usual dose range: 50-600 mg/24 hours
- Converting from a 24-hour SC ketamine infusion to oral ketamine
- • Oral ketamine is more potent than SC ketamine (due to liver metabolism). Many patients require a dose reduction of 25-50% when changing to oral ketamine.
- • Titrate dose in 5-10 mg increments
- • Some specialists stop the SC infusion when the first dose of oral ketamine is given. Others gradually reduce the infusion dose as the oral dose is increased.
Side effects 
Short term 
Long term 
Because ketamine is typically administered as a few repeated doses in a clinical setting, long-term effects are primarily reported and investigated in recreational ketamine users and in animal models.
Neurological effects 
Chronic use of ketamine may lead to cognitive impairments, including memory problems. In 1989, psychiatry professor John Olney reported ketamine caused irreversible changes in two small areas of the rat brain, which, however, has significant differences in metabolism from the human brain, so may not occur in humans.
The first large-scale, longitudinal study of ketamine users found that frequent ketamine users (at least 4 days/week, averaging 20 days/month) had increased depression and impaired memory by several measures, including verbal, short-term memory and visual memory. However, infrequent (1–4 days/month, averaging 3.25 days/month) ketamine users and former ketamine users were not found to differ from controls in memory, attention and psychological well-being tests. This suggests the infrequent use of ketamine does not cause cognitive deficits, and that any deficits that might occur may be reversible when ketamine use is discontinued. However, abstinent, frequent, and infrequent users all scored higher than controls on a test of delusional symptoms.
Short-term exposure of cultures of GABAergic neurons to ketamine at high concentrations led to a significant loss of differentiated cells in one study, and non-cell-death-inducing concentrations of ketamine (10 μg/ml) may still initiate long-term alterations of dendritic arbor in differentiated neurons. The same study also demonstrated chronic (>24 h) administration of ketamine at concentrations as low as 0.01 μg/ml can interfere with the maintenance of dendritic arbor architecture. These results raise the possibility that chronic exposure to low, subanesthetic concentrations of ketamine, while not affecting cell survival, could still impair neuronal morphology and thus might lead to dysfunctions of neural networks.
More recent studies of ketamine-induced neurotoxicity have focused on primates in an attempt to use a more accurate model than rodents. One such study administered daily ketamine doses consistent with typical recreational doses (1 mg/kg IV) to adolescent cynomolgus monkeys for varying periods of time. Decreased locomotor activity and indicators of increased cell death in the prefrontal cortex were detected in monkeys given daily injections for six months, but not those given daily injections for one month.
Urinary tract effects 
According to a recent systematic review, 110 documented reports of irritative urinary tract symptoms from ketamine dependence exist. Urinary tract symptoms have been collectively referred as "ketamine-induced ulcerative cystitis" or "ketamine-induced vesicopathy", and they include urge incontinence, decreased bladder compliance, decreased bladder volume, detrusor overactivity, and painful haematuria (blood in urine). Bilateral hydronephrosis and renal papillary necrosis have also been reported in some cases. The pathogenesis of papillary necrosis has been investigated in mice, and mononuclear inflammatory infiltration in the renal papilla resulting from ketamine dependence has been sugested as a possible mechanism.
The time of onset of lower urinary tract symptoms varies depending, in part, on the severity and chronicity of ketamine use; however, it is unclear whether the severity and chronicity of ketamine use corresponds linearly to the presentation of these symptoms. All reported cases where the user consumed greater than 5 grams per day reported symptoms of the lower urinary tract. Urinary tract symptoms appear to be most common in daily ketamine abusers who have abused the drug for an extended period of time. These symptoms have presented in only one case of medical use of ketamine. However, following dose reduction, the symptoms remitted.
Management of these symptoms primarily involves ketamine cessation, for which compliance is low. Other treatments have been used, including antibiotics, NSAIDS, steroids, anticholinergics, and cystodistension. Both hyaluronic acid instillation and combined pentosan polysulphate and ketamine cessation have been shown to provide relief in some patients, but in the latter case, it is unclear whether relief resulted from ketamine cessation, administration of pentosan polysulphate, or both. Further follow-up is required to fully assess the efficacy of these treatments.
Case reports of hepatotoxicity in chronic pain management 
In case reports of three patients treated with S(+)ketamine for relief of chronic pain, liver enzyme abnormalities occurred following repeat treatment with ketamine infusions, with the liver enzyme values returning below the upper reference limit of normal range on cessation of the drug. The result suggests liver enzymes must be monitored during such treatment.
Drug interactions 
Mechanism of action 
- Central nervous system
Ketamine is a noncompetitive NMDA receptor (NMDAR) antagonist. More specifically, ketamine binds to the allosteric site of the NMDA receptor, effectively inhibiting its channel. The S(+) and R(-) stereoisomers bind with different affinities: Ki = 3200 and 1100 nM, respectively. NMDAR antagonism effects analgesia by preventing central sensitization in dorsal horn neurons; in other words, ketamine's actions interfere with pain transmission in the spinal cord. Ketamine also inhibits nitric oxide synthase, inhibiting production of nitric oxide, a neurotransmitter involved in pain perception, and hence further contributing to analgesia. It also interacts with sigma and opioid receptors, but with lower affinity and without significantly contributing to analgesia.
Ketamine also interacts with a host of other receptors to effect analgesia. It blocks voltage-sensitive calcium channels and depresses sodium channels, attenuating hyperalgesia; it alters cholinergic neurotransmission, which is implicated in pain mechanisms; and it acts as a noradrenergic and serotonergic uptake inhibitor, which are involved in descending antinociceptive pathways.
- Peripheral systems
- Cardiovascular: Ketamine inhibits reuptake of catecholamines, stimulating the sympathetic nervous system, resulting in cardiovascular symptoms.
- Gastrointestinal: Inhibition of neuronal uptake and increased serotonergic activity are thought to underly nausea and vomiting.
- Respiratory: Induced catecholamine release and stimulation of β2 adrenergic receptors causes bronchodilation.
Ketamine is absorbable via intravenous, intramuscular, oral, and topical routes due to both its water and lipid solubilities. When administered orally, it undergoes first-pass metabolism, where it is biotransformed in the liver by CYP3A4 (major), CYP2B6 (minor), and CYP2C9 (minor) isoenzymes into norketamine (through N-demethylation) and finally dehydronorketamine. Intermediate in the biotransformation of norketamine into dehydronorketamine is the hydroxylation of norketamine into 5-hydroxynorketamine by CYP2B6 and CYP2A6. Dehydronorketamine, followed by norketamine, is the most prevalent metabolite detected in urine. As the major metabolite of ketamine, norketamine is one-third to one-fifth as potent anesthetically, and plasma levels of this metabolite are three times higher than ketamine following oral administration. Bioavailability through the oral route reaches 17-20%; bioavailability through other routes are as follows: 93% intramuscularly, 25-50% intranasally, 30% sublingually, and 30% rectally. Peak plasma concentrations are reached within a minute intravenously, 5–15 min intramuscularly, and 30 min orally. Ketamine's duration of action in a clinical setting is 30 min to 2 h intramuscularly and 4–6 h orally.
Ketamine is synthesized from 2-chlorobenzonitrile, which reacts with the Grignard reagent cyclopentylmagnesium bromide to give 1-(2-chlorobenzoyl)cyclopentane. The next step is bromination using bromine to the corresponding bromoketone, which upon reaction with an aqueous solution of methylamine forms the methylimino derivative. During this reaction, a simultaneous hydrolysis of the tertiary bromine atom occurs. On heating the reaction product in decalin, a ring-expansion rearrangement occurs, forming ketamine.
Medical use 
Ketamine was originally developed in 1965 as a derivative of phencyclidine (PCP), which was synthesized in 1926, a feat made possible by the discovery of a new organic Grignard reaction by Parke-Davis scientist Harold Maddox. Initially known as CI-581, ketamine was first synthesized by Parke-Davis scientist Calvin Stevens. Pharmacological investigations in human subjects began in 1964. These investigations demonstrated that ketamine's shorter duration of action and lesser psychotomimetic profile made it favorable over PCP as a "dissociative" anesthetic. Following FDA approval in 1970, ketamine anesthesia was first given to American soldiers during the Vietnam War.
Nonmedical use 
Nonmedical use of ketamine was documented in the early 1970s in underground literature (see The Fabulous Furry Freak Brothers). It was used in psychiatric and other academic research through the 1970s, culminating in 1978 with the publishing of psychonaut John Lilly's The Scientist and Marcia Moore and Howard Alltounian's Journeys into the Bright World, which documented the unusual phenomenology of ketamine intoxication. The incidence of nonmedical ketamine use increased through the end of the century, especially in the context of raves and other parties. However, its emergence as a club drug differs from other club drugs (e.g. MDMA) due to its anesthetic properties (e.g., slurred speech, immobilization) at higher doses; in addition, reports of ketamine being sold as "ecstasy" are common. The use of ketamine as part of a "post-clubbing experience" has also been documented. Ketamine's rise in the dance culture was most rapid in Hong Kong by the end of the 1990s.
Society and culture 
Legal status 
The increase in illicit use prompted ketamine's placement in Schedule III of the United States Controlled Substance Act in August 1999. In the United Kingdom, it became labeled a Class C drug on 1 January 2006. In Canada, ketamine is classified as a Schedule I narcotic, as of August 2005. In Hong Kong, as of 2000, ketamine is regulated under Schedule 1 of Hong Kong Chapter 134 Dangerous Drugs Ordinance. It can only be used legally by health professionals, for university research purposes, or with a physician's prescription. By 2002, ketamine was classified as schedule III in Taiwan; given the recent rise in prevalence in East Asia; however, rescheduling into schedule I or II is being considered.
International brand names 
Brand names for ketamine vary internationally:
Recreational use 
Ketamine sold illicitly comes either from diverted legitimate supplies and semilegitimate suppliers, or from theft of legitimate suppliers. It produces effects similar to phencyclidine (PCP) and dextromethorphan (DXM).
Unlike the other well-known dissociatives PCP and DXM, ketamine is very short-acting, its hallucinatory effects lasting 60 minutes when insufflated or injected and up to two hours when ingested orally, the total experience lasting no more than a few hours. At subanesthetic doses, ketamine produces a dissociative state, characterised by a sense of detachment from one's physical body and the external world which is known as depersonalization and derealization. At sufficiently high doses, users may experience what is called the "K-hole", a state of extreme dissociation with visual and auditory hallucinations. John C. Lilly, Marcia Moore and D. M. Turner (amongst others) have written extensively about their own entheogenic use of, and psychonautic experiences with, ketamine. Both Moore and Turner died prematurely in a way that has been indirectly linked to the sedative properties of ketamine.
Antidepressant use 
When treating patients suffering from complex regional pain syndrome (CRPS) with a low-dose (subanesthetic) ketamine infusion, some patients were observed to make a significant recovery from associated depression. This recovery was not formally documented, as the primary concern was pain management. It was not possible to quantify to what degree depression recovery was secondary to the patient's recovery from CRPS.
One trial administered a short-term ketamine regimen to patients with severe depression, with the dose carefully monitored to prevent hallucinogenic side effects. The patients' normal medications were continued, as it was feared that stopping them might result in severe depressive episodes. Before and following each treatment with ketamine, at patient clinic visits, the Beck Depression Inventory and the Hamilton Rating Scale for Depression were obtained. Two of the patients demonstrated significant, long-term improvement. Another small study found ketamine significantly improved treatment-resistant major depression within hours of injection. The improvement lasted up to one week after the single dose. These patients were previously treatment-resistant, having tried an average of six other treatments that failed. NIMH director Dr. Thomas Insel remarked:
"To my knowledge, this is the first report of any medication or other treatment that results in such a pronounced, rapid, prolonged response with a single dose. These were very treatment-resistant patients."
The researchers apparently attribute the effect to ketamine being an NMDA receptor antagonist. Those findings of Zarate et al. corroborate earlier findings by Berman et al.. However, Zarate et al. do raise some concerns about their results due to a possible lack of blinding, because of the inebriating effects of low-dose ketamine infusion, and future studies are recommended to include an active placebo.
These findings are corroborated by Liebrenz et al., who successfully, according to an attending doctor, treated a patient with a treatment-resistant major depression and a co-occurring alcohol and benzodiazepine dependence by giving an intravenous infusion of 0.5 mg/kg ketamine over a period of 50 minutes, and Goforth et al. who helped a patient with severe, recurrent major depressive disorder that demonstrated marked improvement within eight hours of receiving a preoperative dose of ketamine and one treatment of electroconvulsive therapy with bitemporal electrode placement.
However, a new study in mice by Zarate et al. showed blocking the NMDA receptor is an intermediate step. According to this study, blocking NMDA increases the activity of another receptor, AMPA, and this boost in AMPA activity is crucial for ketamine’s rapid antidepressant actions. NMDA and AMPA are receptors for the neurotransmitter glutamate. The glutamate system has been implicated in depression recently. This is a departure from previous thinking, which had focused on serotonin and norepinephrine. The glutamate system may represent a new avenue for treatment and research.
Krystal et al. retrospectively compared the seizure duration, ictal EEG, and cognitive side effects of ketamine and methohexital anesthesia with ECT in 36 patients. Ketamine was well tolerated and prolonged seizure duration overall, but particularly in those who had a seizure duration shorter than 25 seconds with methohexital at the maximum available stimulus intensity. Ketamine also increased midictal EEG slow-wave amplitude. Thus, a switch to ketamine may be useful when eliciting a robust seizure is difficult. Faster post-treatment reorientation with ketamine may suggest a lower level of associated cognitive side effects.
Kudoh et al. investigated whether ketamine is suitable for depressed patients who had undergone orthopedic surgery. Depressed mood, suicidal tendencies, somatic anxiety, and hypochondriasis significantly decreased in the active group as compared with the control. The group receiving ketamine also had significantly lower postoperative pain.
Acute administration of ketamine at the higher dose, but not imipramine, increased BDNF protein levels in the rat hippocampus. The increase of hippocampal BDNF protein levels induced by ketamine might be necessary to produce a rapid onset of antidepressant action in rats.
Treatment of addiction 
The Russian doctor Evgeny Krupitsky (Clinical Director of Research for the Saint Petersburg Regional Center for Research in Addiction and Psychopharmacology) has claimed to have encouraging results by using ketamine as part of a treatment for alcohol addiction which combines psychedelic and aversive techniques. This method involved psychotherapy, controlled ketamine use, and group therapy, and resulted in 60 of the 86 alcoholic males selected for the study remaining fully abstinent through one year of treatment. For heroin addiction, the same researcher reached the conclusion that one ketamine-assisted psychotherapy session was significantly more effective than active placebo in promoting abstinence from heroin during one year without any adverse reactions. In a recently published study, 59 detoxified inpatients with heroin dependence received a ketamine-assisted psychotherapy (KPT) session prior to their discharge from an addiction treatment hospital, and were then randomized into two treatment groups.
Participants in the first group received two addiction counseling sessions followed by two KPT sessions (with a single IM injection of 2 mg/kg ketamine), with sessions scheduled on a monthly interval (multiple KPT group). Participants in the second group received two addiction counseling sessions on a monthly interval, but no additional ketamine therapy sessions (single KPT group). At one-year follow-up, survival analysis demonstrated a significantly higher rate of abstinence in the multiple KPT group. Thirteen of 26 subjects (50%) in the multiple KPT group remained abstinent, compared to 6 of 27 subjects (22.2%) in the single KPT group (p < 0.05). No differences between groups were found in depression, anxiety, craving for heroin, or their understanding of the meaning of their lives. Three sessions of ketamine-assisted psychotherapy were found to be more effective than a single session for the treatment of heroin addiction.
Krupitsky and Kolp summarized their work to date in 2007.
Jovaisa et al. from Lithuania demonstrated attenuation of opiate withdrawal symptoms with ketamine. A total of 58 opiate-dependent patients were enrolled in a randomized, placebo-controlled, double-blind study. Patients underwent rapid opiate antagonist induction under general anesthesia. Prior to opiate antagonist induction, patients were given either placebo (normal saline) or a subanesthetic ketamine infusion of 0.5 mg/kg·h. The ketamine group presented better control of withdrawal symptoms, which lasted beyond ketamine infusion itself. Significant differences between ketamine and control groups were noted in anesthetic and early postanesthetic phases. No differences in effects on outcome after four months were observed.
Complex regional pain syndrome 
Ketamine is being used as an experimental and controversial treatment for complex regional pain syndrome (CRPS), also known as reflex sympathetic dystrophy (RSD). CRPS/RSD is a severe chronic pain condition characterized by sensory, autonomic, motor, and dystrophic signs and symptoms. The pain in CRPS is continuous, worsens over time, and is usually disproportionate to the severity and duration of the inciting event. The hypothesis is that ketamine manipulates NMDA receptors which might reboot aberrant brain activity. One treatment modality is a low-dose ketamine infusion of between 25 and 90 mg per day, over five days, either in hospital or as an outpatient, called the awake technique. Open label, prospective, pain journal evaluation of a 10-day infusion of intravenous ketamine (awake technique) in the CRPS patient concluded, "A four-hour ketamine infusion escalated from 40–80 mg over a 10-day period can result in a significant reduction of pain with increased mobility and a tendency to decreased autonomic dysregulation".
Case notes of 33 patients whose CRPS pain was treated by the inpatient administration of a continuous subanesthetic intravenous infusion of ketamine were reviewed at Mackay Base Hospital, Queensland, Australia. A total of 33 patients with diagnoses of CRPS who had undergone ketamine treatment at least once were identified. Due to relapse, 12 of 33 patients received a second course of therapy, and two of 33 patients received a third. There was complete pain relief in 25 (76%), partial relief in six (18%), and no relief in two (6%) patients.
The degree of relief obtained following repeat therapy (N=12) appeared even better, as all 12 patients who received second courses of treatment experienced complete relief of their CRPS pain. The duration of relief was also impressive, as was the difference between the duration of relief obtained after the first and after the second courses of therapy. In this respect, following the first course of therapy, 54% of 33 individuals remained pain-free for three months or more and 31% remained pain free for six months or more. After the second infusion, 58% of 12 patients experienced relief for a year or more, while almost 33% remained pain free for over three years. The most frequent side effect observed in patients receiving this treatment was a feeling of inebriation. Hallucinations occurred in six patients. Less-frequent side effects also included complaints of light-headedness, dizziness, and nausea. In four patients, an alteration in hepatic enzyme profile was noted; the infusion was terminated and the abnormality resolved thereafter. No long-term side effects were noted. This procedure has only recently been allowed in the United States for the treatment of CRPS.
A second treatment modality consists of putting the patient into a medically induced coma and giving an extremely high dosage of ketamine, typically between 600 and 900 mg. This version, previously done in Germany and Mexico, is now currently only preformed in the United States.According to Dr Schwartzman, 14 of 41 patients in the coma-induced ketamine experiments were completely cured. "We haven't cured the original injury", he says, "but we have cured the RSD or kept it in remission. The RSD pain is gone." He added, "No one ever cured it before... In 40 years, I have never seen anything like it. These are people who were disabled and in horrible pain. Most were completely incapacitated. They go back to work, back to school, and are doing everything they used to do. Most are on no medications at all. I have taken morphine pumps out of people. You turn off the pain and reset the whole system."
In Tuebingen, Germany, Dr Kiefer treated a patient who presented with a rapidly progressing contiguous spread of CRPS from a severe ligamentous wrist injury. Standard pharmacological and interventional therapy successively failed to halt the spread of CRPS from the wrist to the entire right arm. Her pain was unmanageable with all standard therapies. As a last treatment option, the patient was transferred to the intensive care unit and treated on a compassionate care basis with anesthetic doses of ketamine in gradually increasing (3–5 mg/kg·h) doses in conjunction with midazolam over a period of five days. On the second day, edema and discoloration began to resolve and increased spontaneous movement was noted. On day six, symptoms completely resolved and infusions were tapered. The patient emerged from anesthesia completely free of pain and associated CRPS signs and symptoms. The patient has maintained this complete remission from CRPS for eight years now. The psychiatric side effects of ketamine were successfully managed with the concomitant use of midazolam and resolved within a month of treatment.
Fear of Harm 
According to a recent report on NPR, Demitri Papolos uses ketamine to treat children with "fear of harm" profile, a condition characterized by: sleep disturbances including frequent and terrifying nightmares; an extreme reaction when anyone tries to control their behavior; and overheating, especially at night. Although "fear of harm" profile has been lumped in with bipolar disorder over the recent decades that understanding is emerging about these concerns, "fear of harm" may be related to an overly-sensitive "flight-or-fight" reaction, which classical bipolar disorder is not.
See also 
- NMDA receptor
- Hijazi, Y.; Boulieu, R. (July 2002). "Contribution of CYP3A4, CYP2B6, and CYP2C9 isoforms to N-demethylation of ketamine in human liver microsomes". Drug Metabolism and Disposition 30 (7): 853–8. doi:10.1124/dmd.30.7.853. PMID 12065445.
- Peck, T. E.; Hill, S. A.; Williams, M. (2008). Pharmacology for anaesthesia and intensive care (3rd edition). Cambridge: Cambridge University Press. p. 111. ISBN 978-0-521-70463-2.
- Bergman, S. A. (1999). "Ketamine: review of its pharmacology and its use in pediatric anesthesia". Anesthesia Progress 46 (1): 10–20. PMC 2148883. PMID 10551055.
- Nancy Diazgranados et al (August 2010). "A Randomized Add-on Trial of an N-methyl-d-aspartate Antagonist in Treatment-Resistant Bipolar Depression". Archives of General Psychiatry 67 (8): 793–802. doi:10.1001/archgenpsychiatry.2010.90. PMC 3000408. PMID 20679587.
- Autry et al. (7 July 2011). "NMDA receptor blockade at rest triggers rapid behavioural antidepressant responses". Nature 475: 91–95.
- Harrison, N. L.; Simmonds, M. A. (February 1985). "Quantitative studies on some antagonists of N-methyl D-aspartate in slices of rat cerebral cortex". British Journal of Pharmacology 84 (2): 381–91. PMC 1987274. PMID 2858237.
- Hirota K, Sikand KS, Lambert DG (1999). "Interaction of ketamine with mu2 opioid receptors in SH-SY5Y human neuroblastoma cells". Journal of Anesthesia 13 (2): 107–9. doi:10.1007/s005400050035. PMID 14530949.
- Narita M, Yoshizawa K, Aoki K, Takagi M, Miyatake M, Suzuki T (September 2001). "A putative sigma1 receptor antagonist NE-100 attenuates the discriminative stimulus effects of ketamine in rats". Addiction Biology 6 (4): 373–376. doi:10.1080/13556210020077091. PMID 11900615.
- Pharmaceutical Society of Australia. Australian Medicines Handbook. 2011. Australian Medicines Handbook Pty Ltd. p. 13. Unknown parameter
- Krüger, A. D. (1998). "Current aspects of using ketamine in childhood". Anaesthesiologie Und Reanimation (in German) 23 (3): 64–71. PMID 9707751.
- "WHO Model List of Essential Medicines" (PDF). World Health Organization. March 2011. Retrieved 2013-05-02.
- Lankenau SE, Sanders B, Bloom JJ, et al. (March 2007). "First injection of ketamine among young injection drug users (IDUs) in three U.S. cities". Drug and Alcohol Dependence 87 (2–3): 183–93. doi:10.1016/j.drugalcdep.2006.08.015. PMC 1852477. PMID 16979848.
- Heshmati F, Zeinali MB, Noroozinia H, Abbacivash R, Mahoori A (December 2003). "Use of ketamine in severe status asthmaticus in intensive care unit". Iranian Journal of Allergy, Asthma, and Immunology 2 (4): 175–80. PMID 17301376.
- Zarate CA Jr, et al (January 2012). "Replication of Ketamine's Antidepressant Efficacy in Bipolar Depression: A Randomized Controlled Add-On Trial.". Biological Psychiatry 71 (11): 939–46. doi:10.1016/j.biopsych.2011.12.010. PMC 22297150. PMID 22297150.
- Krystal JH, Madonick S, Perry E, et al. (August 2006). "Potentiation of low dose ketamine effects by naltrexone: potential implications for the pharmacotherapy of alcoholism". Neuropsychopharmacology 31 (8): 1793–800. doi:10.1038/sj.npp.1300994. PMID 16395307.
- Jovaisa T, Laurinenas G, Vosylius S, Sipylaite J, Badaras R, Ivaskevicius J (2006). "Effects of ketamine on precipitated opiate withdrawal". Medicina 42 (8): 625–34. PMID 16963828.
- Lynch ME, Clark AJ, Sawynok J, Sullivan MJ (October 2005). "Topical amitriptyline and ketamine in neuropathic pain syndromes: an open-label study". The Journal of Pain 6 (10): 644–9. doi:10.1016/j.jpain.2005.04.008. PMID 16202956.
- Elia N, Tramèr MR (January 2005). "Ketamine and postoperative pain--a quantitative systematic review of randomised trials". Pain 113 (1–2): 61–70. doi:10.1016/j.pain.2004.09.036. PMID 15621365.
- Saito O, Aoe T, Kozikowski A, Sarva J, Neale JH, Yamamoto T (September 2006). "Ketamine and N-acetylaspartylglutamate peptidase inhibitor exert analgesia in bone cancer pain". Canadian Journal of Anesthesia 53 (9): 891–8. doi:10.1007/BF03022832. PMID 16960267.
- Adams HA (December 1997). "[S-(+)-ketamine. Circulatory interactions during total intravenous anesthesia and analgesia-sedation]". Der Anaesthesist (in German) 46 (12): 1081–7. doi:10.1007/s001010050510. PMID 9451493.
- Correll GE, Maleki J, Gracely EJ, Muir JJ, Harbut RE (September 2004). "Subanesthetic ketamine infusion therapy: a retrospective analysis of a novel therapeutic approach to complex regional pain syndrome". Pain Medicine 5 (3): 263–75. doi:10.1111/j.1526-4637.2004.04043.x. PMID 15367304.
- "Severe Pain Relief may be Possible with a Common Anesthetic Drug" (Press release). Blackwell Publishing. 1 October 2004. Retrieved 13 December 2009.
- Fujikawa DG (1995). "Neuroprotective Effect of Ketamine Administered After Status Epilepticus Onset". Epilepsia 36 (2): 186–195. doi:10.1111/j.1528-1157.1995.tb00979.x. PMID 7821277.
- Lundberg GD (2008). "Postoperative Ketamine Can Reduce Morphine Consumption and Nausea". The Medscape Journal of Medicine 10 (10): 234. PMC 2605142.
- Quibell, Rachel; Prommer, Eric E., Mihalyo, Mary, Twycross, Robert, Wilcock, Andrew (1 March 2011). "Ketamine*". Journal of Pain and Symptom Management 41 (3): 640–649. doi:10.1016/j.jpainsymman.2011.01.001. PMID 21419322.
- Morgan, Celia J. A.; Curran, H. Valerie (1 January 2012). "Ketamine use: a review". Addiction 107 (1): 27–38. doi:10.1111/j.1360-0443.2011.03576.x. PMID 21777321.
- Okon T (May 2007). "Ketamine: an introduction for the pain and palliative medicine physician". Pain Physician 10 (3): 493–500. PMID 17525784.
- Olney JW, Labruyere J, Price MT (June 1989). "Pathological changes induced in cerebrocortical neurons by phencyclidine and related drugs". Science 244 (4910): 1360–2. doi:10.1126/science.2660263. PMID 2660263.
- Erowid DXM Vaults: Health: The Bad News Isn't In: A Look at Dissociative-Induced Brain Damage, by Anderson C
- Tryba M, Gehling M (October 2002). "Clonidine--a potent analgesic adjuvant". Current Opinion in Anaesthesiology 15 (5): 511–7. doi:10.1097/00001503-200210000-00007. PMID 17019247.
- Morgan, Celia J. A.; Muetzelfeldt, Leslie; Curran, H. Valerie (2009). "Consequences of chronic ketamine self-administration upon neurocognitive function and psychological wellbeing: a 1-year longitudinal study". Addiction 105 (1): 121–33. doi:10.1111/j.1360-0443.2009.02761.x. PMID 19919593.
- Vutskits L, Gascon E, Potter G, Tassonyi E, Kiss JZ (May 2007). "Low concentrations of ketamine initiate dendritic atrophy of differentiated GABAergic neurons in culture". Toxicology 234 (3): 216–26. doi:10.1016/j.tox.2007.03.004. PMID 17418473.
- Hargreaves RJ, Hill RG, Iversen LL (1994). "Neuroprotective NMDA antagonists: the controversy over their potential for adverse effects on cortical neuronal morphology". Acta Neurochirurgica. Supplementum 60: 15–9. PMID 7976530.
- Sun, Lin; Qi Li, Qing Li, Yuzhe Zhang, Dexiang Liu, Hong Jiang, Fang Pan, David T. Yew (November 2012). "Chronic ketamine exposure induces permanent impairment of brain functions in adolescent cynomolgus monkeys". Addiction Biology. doi:10.1111/adb.12004. PMID 23145560.
- Middela, S.; Pearce, I. (1 January 2011). "Ketamine-induced vesicopathy: a literature review". International Journal of Clinical Practice 65 (1): 27–30. doi:10.1111/j.1742-1241.2010.02502.x. PMID 21155941.
- Yeung, LY; Rudd, JA, Lam, WP, Mak, YT, Yew, DT (2009-12-15). "Mice are prone to kidney pathology after prolonged ketamine addiction". Toxicology letters 191 (2–3): 275–8. doi:10.1016/j.toxlet.2009.09.006. PMID 19766175.
- PAIN Volume 152, Issue 9, September 2011, Pages 1946-1947
- Hirota, K; Lambert, DG (1996 Oct). "Ketamine: its mechanism(s) of action and unusual clinical uses". British journal of anaesthesia 77 (4): 441–4. PMID 8942324.
- Aroni, F; Iacovidou, N, Dontas, I, Pourzitaki, C, Xanthos, T (2009 Aug). "Pharmacological aspects and potential new clinical applications of ketamine: reevaluation of an old drug". Journal of clinical pharmacology 49 (8): 957–64. doi:10.1177/0091270009337941. PMID 19546251.
- Rowland, LM (2005 Jul). "Subanesthetic ketamine: how it alters physiology and behavior in humans". Aviation, space, and environmental medicine 76 (7 Suppl): C52–8. PMID 16018330.
- Meller, ST (1996 Dec). "Ketamine: relief from chronic pain through actions at the NMDA receptor?". Pain 68 (2–3): 435–6. doi:10.1016/S0304-3959(96)03167-3. PMID 9121834.
- Aroni, F.; Iacovidou, N., Dontas, I., Pourzitaki, C., Xanthos, T. (22 June 2009). "Pharmacological Aspects and Potential New Clinical Applications of Ketamine: Reevaluation of an Old Drug". The Journal of Clinical Pharmacology 49 (8): 957–964. doi:10.1177/0091270009337941. PMID 19546251.
- Sinner, B; Graf, BM (2008). "Ketamine". Handbook of experimental pharmacology. Handbook of Experimental Pharmacology 182 (182): 313–33. doi:10.1007/978-3-540-74806-9_15. ISBN 978-3-540-72813-9. PMID 18175098.
- Li, Jih-Heng; Kasinather, Vickna, Cheung, Zhou, Nurhidayat, Jarlais, Des, Schottenfeld, Richard (1 March 2011). "To use or not to use: an update on licit and illicit ketamine use". Substance Abuse and Rehabilitation: 11. doi:10.2147/SAR.S15458.
- Haas, DA; Harper, DG (1992). "Ketamine: a review of its pharmacologic properties and use in ambulatory anesthesia". Anesthesia progress 39 (3): 61–8. PMC 2148758. PMID 1308374.
- C.L. Stevens, U.S. Patent 3,254,124 (1966)
- C.L. Stevens, BE 634208 (1963
- Domino, EF (2010 Sep). "Taming the ketamine tiger. 1965". Anesthesiology 113 (3): 678–84. doi:10.1097/ALN.0b013e3181ed09a2. PMID 20693870.
- Corssen, G; Domino, EF (1966 Jan-Feb). "Dissociative anesthesia: further pharmacologic studies and first clinical experience with the phencyclidine derivative CI-581". Anesthesia and Analgesia 45 (1): 29–40. PMID 5325977.
- Alltounian, Howard Sunny; Marcia Moore (1978). Journeys into the bright world. Rockport, Mass: Para Research. ISBN 0-914918-12-5.[page needed]
- Awuonda, Moussa (1 July 1996). "Swedes alarmed at ketamine misuse". The Lancet 348 (9020): 122. doi:10.1016/S0140-6736(05)64628-4.
- Curran, HV; Morgan, C (2000 Apr). "Cognitive, dissociative and psychotogenic effects of ketamine in recreational users on the night of drug use and 3 days later". Addiction (Abingdon, England) 95 (4): 575–90. doi:10.1046/j.1360-0443.2000.9545759.x. PMID 10829333.
- Gahlinger, PM (2004-06-01). "Club drugs: MDMA, gamma-hydroxybutyrate (GHB), Rohypnol, and ketamine". American family physician 69 (11): 2619–26. PMID 15202696.
- Jansen, KL (1993-03-06). "Non-medical use of ketamine". BMJ (Clinical research ed.) 306 (6878): 601–2. doi:10.1136/bmj.306.6878.601. PMC 1676978. PMID 8461808.
- Joe-Laidler, Karen; Hunt, Geoffery (1 January 2008). "Sit Down to Float: The Cultural Meaning of Ketamine Use in Hong Kong". Addiction Research & Theory 16 (3): 259–271. doi:10.1080/16066350801983673.
- Parker, Fiona Measham, Judith Aldridge, Howard (2001). Dancing on drugs : risk, health and hedonism in the British club scene. London: Free Association. ISBN 1-85343-512-0.
- Moore, Karenza; Measham, Fiona (1 January 2006). "Ketamine use: minimising problems and maximising pleasure". Drugs and Alcohol Today 6 (3): 29–32. doi:10.1108/17459265200600047.
- "Ketamine - Schedule III of The Controlled Substances Act (CSA)". Anestesiología Mexicana en Internet. Retrieved 2006-12-22.
- "Club 'horse' drug to be outlawed". BBC News. 28 December 2005. Retrieved 7 May 2010.
- Controlled Drugs and Substances Act
- Government to tighten control on Ketamine
- Lexi-Comp. "Ketamine Drug Information". The Merck Manuals. Retrieved 6 January 2012.
- Giannini AJ, Loiselle RH, Giannini MC, Price WA (1985). "Phencyclidine and the dissociatives". Psychiatric Medicine 3 (3): 197–217. PMID 2893430.
- Giannini AJ, Underwood NA, Condon M (November 2000). "Acute ketamine intoxication treated by haloperidol: a preliminary study". American Journal of Therapeutics 7 (6): 389–91. doi:10.1097/00045391-200007060-00008. PMID 11304647.
- Giannini AJ (1999). Drug Abuse. Los Angeles: Health Information Press. p. 104. ISBN 1-885987-11-0.[page needed]
- Lilly, John Cunningham (1997). The scientist: a metaphysical autobiography. Berkeley, CA: Ronin Pub. ISBN 0-914171-72-0.[page needed]
- Alltounian, Howard Sunny; Marcia Moore (1978). Journeys into the bright world. Rockport, Mass: Para Research. ISBN 978-0-914918-12-7.[page needed]
- Turner, D. M. (1994). The essential psychedelic guide. San Francisco, CA: Panther Press. ISBN 0-9642636-1-0.[page needed]
- Jansen, Karl (2001). Ketamine: Dreams and Realities. Multidisciplinary Association for Psychedelic Studies. pp. 50, 89. ISBN 0-9660019-3-1.
- Correll GE, Futter GE (2006). "Two case studies of patients with major depressive disorder given low-dose (subanesthetic) ketamine infusions". Pain Medicine 7 (1): 92–5. doi:10.1111/j.1526-4637.2006.00101.x. PMID 16533209.
- NIH. "Experimental Medication Kicks Depression in Hours Instead of Weeks" NIH News, 7 August 2006
- Khamsi, R. "Ketamine relieves depression within hours" New Scientist, 8 August 2006.
- Zarate CA, Singh JB, Carlson PJ, et al. (August 2006). "A randomized trial of an N-methyl-D-aspartate antagonist in treatment-resistant major depression". Archives of General Psychiatry 63 (8): 856–64. doi:10.1001/archpsyc.63.8.856. PMID 16894061.
- Berman RM, Cappiello A, Anand A, et al. (February 2000). "Antidepressant effects of ketamine in depressed patients". Biological Psychiatry 47 (4): 351–4. doi:10.1016/S0006-3223(99)00230-9. PMID 10686270.
- Liebrenz M, Borgeat A, Leisinger R, Stohler R (April 2007). "Intravenous ketamine therapy in a patient with a treatment-resistant major depression". Swiss Medical Weekly 137 (15–16): 234–6. PMID 17525879.
- Goforth HW, Holsinger T (March 2007). "Rapid relief of severe major depressive disorder by use of preoperative ketamine and electroconvulsive therapy". The Journal of ECT 23 (1): 23–5. doi:10.1097/01.yct.0000263257.44539.23. PMID 17435569.
- Faster-Acting Antidepressants Closer to Becoming a Reality", NIMH, 25 July 2007
- Krystal AD, Weiner RD, Dean MD, et al. (2003). "Comparison of seizure duration, ictal EEG, and cognitive effects of ketamine and methohexital anesthesia with ECT". The Journal of Neuropsychiatry and Clinical Neurosciences 15 (1): 27–34. doi:10.1176/appi.neuropsych.15.1.27. PMID 12556568.
- Kudoh A, Takahira Y, Katagai H, Takazawa T (July 2002). "Small-dose ketamine improves the postoperative state of depressed patients". Anesthesia and Analgesia 95 (1): 114–8, table of contents. doi:10.1097/00000539-200207000-00020. PMID 12088953.
- Garcia LS, Comim CM, Valvassori SS, et al. (January 2008). "Acute administration of ketamine induces antidepressant-like effects in the forced swimming test and increases BDNF levels in the rat hippocampus". Progress in Neuro-psychopharmacology & Biological Psychiatry 32 (1): 140–4. doi:10.1016/j.pnpbp.2007.07.027. PMID 17884272.
- The Combination of Psychedelic and Aversive Approaches in Alcoholism Treatment - Eleusis
- Krupitsky EM, Grinenko AY (1997). "Ketamine psychedelic therapy (KPT): a review of the results of ten years of research". Journal of Psychoactive Drugs 29 (2): 165–83. doi:10.1080/02791072.1997.10400185. PMID 9250944.
- Krupitsky EM, Burakov AM, Dunaevsky IV, Romanova TN, Slavina TY, Grinenko AY (March 2007). "Single versus repeated sessions of ketamine-assisted psychotherapy for people with heroin dependence". Journal of Psychoactive Drugs 39 (1): 13–9. doi:10.1080/02791072.2007.10399860. PMID 17523581.
- Krupitsky; Kolp. "Ketamine Psychedelic Psychotherapy". In Michael J. Winkelman and Thomas B., Roberts. Psychedelic Medicine: New Evidence for Hallucinogens as Treatments. Westport, CT: Praeger/Greenwood.[page needed]
- Goldberg ME, Domsky R, Scaringe D, et al. (April 2005). "Multi-day low dose ketamine infusion for the treatment of complex regional pain syndrome". Pain Physician 8 (2): 175–9. PMID 16850072.
- CNN report on ketamine therapy for CRPS/RSD 1 September 2006
- Kiefer RT, Rohr P, Ploppa A, Altemeyer KH, Schwartzman RJ (June 2007). "Complete recovery from intractable complex regional pain syndrome, CRPS-type I, following anesthetic ketamine and midazolam". Pain Practice 7 (2): 147–50. doi:10.1111/j.1533-2500.2007.00123.x. PMID 17559485.
- The Merck Manual: Ketamine
- Ketamine on RxList
- DEA: Ketamine Fact Sheet
- Center for Substance Abuse Research: Ketamine