Ketamine

K, special K, vitamin K

Ketamine (Ketamine hydrochloride) is a dissociative general anaesthetic. 

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 (PCP), and it is still widely used  as an anaesthetic due to its safety profile and low toxicity. Doctors and vets  use this drug because it produces analgesia (pain relief) and amnesia.  It is considered a safer alternative to general anaesthetic for some people  (for example, older people and children) because it doesn’t slow down a person’s breathing or heart rate.

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. It is usually sold in ‘bumps’ (a small amount of powder) or grams. Ketamine is usually snorted (a bump is snorted through a small glass nasal inhaler called a ‘bumper’) although it can also be swallowed, smoked or injected. 

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
  • dissociation
  • hallucinations
  • a sense of floating
  • amnesia
  • nausea and vomiting.

Used in small doses, it produces feelings of dissociation, helping the user to feel separated or detached from their body and/or environment. It also has hallucinogenic effects and can impact on the senses and on a person’s perception of reality. At higher doses, ketamine users can experience an ‘emergent state’ also called a ‘K-hole’, which is a trip-like experience that varies from person to person. The effects of the emergent state can begin as soon as 5 to 10 minutes after first taking the drug and can begin with the user being unable to move followed by a total disconnect from physical sensations as hallucinations start to manifest. Risks of this dissociative state include: hallucinations, disorientation, sense of invincibility, inability to communicate  with others, and a limited awareness of surrounding environment.

The effects of ketamine may come on quickly, within 5 to 15 minutes,  and may last from 45 to 60 minutes. 

Long-term effects

Chronic heavy use of ketamine can lead to urinary tract damage including pain and ulceration in the bladder, bladder shrinkage and incontinence. This can be referred to as ‘ketamine bladder syndrome’ or ‘ketamine cystitis’.

Frequent use is also associated with memory impairment.

Some regular users of ketamine 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.

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

Some drugs may affect the recovery from ketamine anaesthesia particularly barbiturates, and opioids. The use of stimulants can also have a negative effect on blood pressure and heart rate. 

Drugs that may affect recovery from ketamine anaesthesia 

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

  • barbiturates such as amobarbital, butabarbital, mephobarbital, secobarbital and phenobarbital
  • opioid medications such as fentanyl, hydrocodone, hydromorphone, methadone, morphine,  oxycodone and propoxyphene. 

Dependence

Non-physical and physical dependence can develop when ketamine is taken on a regular basis.

Withdrawal

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, typically lasting 4-6 weeks after last use. This may be due more to the sedative norketamine (a product of the breakdown of ketamine) lingering in the bloodstream. 

Overdose

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

Treatment

Evidence from better-researched drugs suggests that services providing good social support, as well as psychological interventions to help maintain motivation and improve coping skills, are likely to be useful.