K, special K, vitamin K

Ketamine is a short-acting general anaesthetic for human and veterinary use. It is usually a powder, though it can also come in liquid form.

Clear liquid in glass bottles with a syringe

Ketamine was first synthesised in the 1960s as part of an effort to find a safer alternative to the anaesthetic phencyclidine, and it is still widely used as an anaesthetic. Its use as a recreational drug began to increase around the beginning of this century.

Ketamine and the law

It is illegal to use, possess, supply, or manufacture ketamine in New South Wales. There are exceptions under the law, for example authorised use by medical practitioners.

How ketamine is used

Ketamine is usually manufactured as a liquid, which is then evaporated to form a powder that can be snorted or dissolved in other liquids and swallowed. A few users have reported injecting it. It can also be smoked, mixed with tobacco or cannabis, in a joint or pipe.

Short-term effects

Ketamine produces a feeling of detachment from one's body and the external world. It does this by reducing or blocking signals to the conscious mind from other parts of the brain, typically the senses.

The short-term effects of ketamine include:

  • a sense of euphoria and wellbeing
  • increased libido
  • drowsiness
  • slurred speech
  • impaired motor coordination
  • hallucinations
  • a sense of floating
  • nausea and vomiting.

The effects of even a small amount of ketamine can resemble an out-of-body experience. Many who take large amounts are convinced that their experiences are real, even though they accept that they have taken a drug. Users may fall into an anaesthetised state, a 'k-hole'. In fact, one of the more serious effects of using ketamine is that a user may harm themselves while anaesthetised. There are stories of people burning or cutting themselves unknowingly while using the drug. Some users have such unpleasant experiences with ketamine that they never try it again. The effects of ketamine may come on quickly, from between 10 to 20 minutes, and may last from 45 to 90 minutes.

Long-term effects

Some regular users experience 'flashbacks'—the spontaneous recurrence of an experience that occurred while the user was under the influence of the drug.

How common is ketamine use?

The 2016 National Drug Strategy Household Survey found that 1.9% of Australians aged 14 and over have ever tried ketamine, while 0.4% used it in the year preceding the survey. 

Ketamine and driving

It is not safe to drive while using ketamine. Drowsiness, impaired motor coordination and hallucinations, can affect the ability to drive include drowsiness and impaired motor co-ordination.

Ketamine and pregnancy

Little is known about the effects of ketamine on an unborn child. However, many drugs and medications taken during pregnancy cross the placenta, or are present in breast milk. It is generally risky to take any drug while pregnant or breastfeeding without medical advice.

Using ketamine with other drugs

It may take longer to recover from anaesthesia with ketamine if a person has recently used some other drugs.


Physical dependence can develop when ketamine is taken on a regular basis.


Ketamine does not appear to produce significant withdrawal symptoms in chronic users. There are anecdotal reports of tension, twitchiness, poor attention span and restlessness in abstinent long-term users, but this may be due more to the sedative norketamine (a product of the breakdown of ketamine) lingering in the bloodstream.


Unlike most anaesthetics, ketamine does not suppress breathing or heart rate, so overdose is unlikely.


Few ketamine users currently seek treatment for their drug use, although as use of the drug increases, this is likely to change. Evidence from betterresearched drugs suggests that services providing good social support, as well as psychological interventions to help maintain motivation and treatment.

Drugs that may affect recovery from ketamine anaesthesia

Drugs that may increase recovery time from anaesthesia with ketamine include:

  • barbiturates such as amobarbital (Amytal), butabarbital (Butisol), mephobarbital (Mebaral), secobarbital (Seconal) and phenobarbital (Luminal, Solfoton)
  • opioid medications such as fentanyl (Actiq, Duragesic, Ionsys), hydrocodone (Lortab, Vicodin), hydromorphone (Dilaudid, Palladone), methadone (Dolophine, Methadose), morphine (Kadian, MS Contin, Oramorph), oxycodone (OxyContin, Percocet, Roxicodone) and propoxyphene (Darvocet, Darvon).