What is Ketamine?

Green, K, Special K, Super K, Vitamin K, Donkey Dust

Ketamine is an anaesthetic with analgesic, stimulant and psychedelic properties. Chemically related to phencyclidine (PCP), it has been used extensively in human and veterinary medicine. Like PCP, it is a ‘dissociative’ anaesthetic which means that patients feel detached and remote from their immediate environment. Users say that under its influence they assume a different point of view, outside of body and self.


liquid pharmaceutical ketamine

The drug comes in a variety of forms. Pharmaceutical ketamine is usually a liquid. On the street it is more common to see tablets or a white crystalline powder.

Powdered ketamine is often snorted, though it may be swallowed.

If sniffed the effects of ketamine generally come on quickly and can last from about 20 minutes to a couple of hours.

The law

Ketamine is controlled as a Class B Drug under the Misuse of Drugs Act 1971.  (It was reclassified from Class C in June 2014).

Penalties for possession are up to five years in prison and/or an unlimited fine. Supply holds penalties of up to 14 years in prison and/or an unlimited fine.

In practice, maximum sentences are rarely used. For more information please see the sentencing page on the Release website.


Ketamine is a dissociative anaesthetic, meaning users will feel detached from themselves and their immediate surroundings. The drug also has painkilling, stimulant and psychedelic effects. Effects are immediate if injected, though this practice is rarer, with most users sniffing the drug. If sniffed, the effects will take around 20 minutes to come on, and can last for one or two hours.

The amount of ketamine taken determines both the extent and type of effect the drug will have. At a relatively low dosage (around 100mg), users will commonly experience mild dissociative effects, hallucinations, and distortions of time and space.

Larger doses (anything above 200mg) may induce a so called ‘K-hole’, where a user can experience considerable and lengthy detachment from reality. The user may experience hallucinations, similar to those while using LSD followed by numbness, often in the limbs, and strange muscle movements. Users may also feel sick or throw up – which can be very dangerous at high doses if the user is unconscious or disorientated as people may choke on their vomit.

Concerns over the risks of using the drug have been growing in recent years. Repeated or heavy use of ketamine appears to be particularly harmful to the urinary tract and can cause ulcerative cystitis, where the bladder wall thickens. In some cases, individuals have had to have their bladders surgically removed. Frequent use can also cause kidney dysfunction and abdominal pains known as ‘K-cramps’.

The risk of death from accidents is also elevated while under the influence of ketamine. As a powerful analgesic, its use can make users more vulnerable to physical injury as the seriousness of an incident may not be immediately apparent. Its dissociative effects may also make users unaware of potentially risky behaviour. One study found that as many as 83% of 90 ketamine users knew of someone who had an accident while taking ketamine.

Frequent use of ketamine may also lead to depression.

There is considerable evidence from ketamine users that heavy use of the drug can lead to dependence. Studies on animals, as well as reports from regular users, suggest that tolerance can develop, meaning that users need to take higher and higher doses to achieve the same effects.

Ketamine can be particularly dangerous if used at the same time as depressant drugs such as alcohol, heroin or tranquillisers. The combined effects of these drugs can cause the body to shut down to such an extent that the lungs or heart may stop functioning.


Ketamine first found its way on to the club and rave scene in the UK in 1992 when people took it thinking they were buying ecstasy.

The DrugScope Street Drug Trends Survey 2011 reported a rise in both use of, and problems associated with, ketamine. Of the twenty areas surveyed by DrugScope, three quarters reported increases both in the general use of ketamine and in the numbers of people coming forward for help with psychological and physical problems associated with the drug.

According to the DrugScope Street Drug Trends Survey 2011, the national average price of ketamine is around £21 per gram.

More recently, Home Office statistics published in 2016, report that ketamine use has fallen among 16 to 59 year olds from 0.5 to 0.3 per cent. The figures showed that around 94,000 adults had used ketamine in England and Wales in the last year. The use of ketamine has remained relatively stable, between 0.3 and 0.6 per cent, since its use was first surveyed in 2006/07.

See also DrugWise’s printable ketamine factsheet (PDF)

Updated December 2016

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