Ketamine factsKetamine. Tablets of different colours and sizes. © Australian Drug Foundation, 2011.

What is ketamine?

Effects of ketamine

Tolerance and dependence

Getting help

Ketamine use in Australia

What is ketamine?

Ketamine hydrochloride is an anaesthetic drug used by veterinarians.

The drug has hallucinogenic effects, which means that it changes thinking, perception of time and emotions, and seeing or hearing things that are distorted, or that do not exist at all.

Some people use ketamine to get "high". It has also been used in drink spiking.

Other names

Special K, K, ket, kitkat or super K.

What it looks like

When sold illegally, ketamine is usually a white crystalline powder. It can also be made into tablets and pills, or dissolved in a liquid.

How is it used?

Ketamine can be swallowed, snorted or injected. It is also sometimes smoked with other substances such as cannabis or tobacco.

Effects of ketamine

The effects of any drug vary from person to person. How ketamine affects a person depends on many things including their size, weight and health, also whether the person is used to taking it and whether other drugs are taken around the same time. The effects of any drug also depend on the amount taken.

There is no safe level of drug use. Use of any drug always carries some risk—even medications can produce unwanted side effects. It is important to be careful when taking any type of drug.

Immediate effects

The effects of ketamine may be experienced within 30 seconds (if injected) up to 20 minutes (if swallowed) and 5–10 minutes (if snorted). The effects of ketamine can last for approximately 45 to 90 minutes.

Low to moderate doses

Higher doses

Some of the effects that may be experienced after taking ketamine include:

  • feelings of euphoria and relaxation
  • feelings of being detached from the body—sometimes known as “falling into a k-hole”
  • hallucinations and distorted perception, including visual, auditory, physical, time and space
  • disorganised thoughts, confusion and difficulty concentrating, thinking or maintaining attention
  • anxiety, agitation, paranoia and feelings of panic
  • slurred speech
  • blurred vision
  • constricted (small) pupils
  • lack of coordination
  • increased but shallow breathing rate
  • increased heart rate and blood pressure
  • nausea and vomiting
  • sweating
  • reduced sensitivity to pain
  • inability to move.

A high dose of ketamine can cause a person to overdose. This means that a person has taken more ketamine than their body can cope with. The risk of overdose increases if the strength or purity of the ketamine is not known.

High doses of ketamine can intensify some of the effects experienced at lower doses. People may also experience:

  • drowsiness
  • temporary paralysis (inability to move)
  • disorganised thought and speech
  • semi-consciousness
  • erratic, hostile or bizarre behaviour
  • feelings of panic or terror
  • paranoia
  • depression
  • amnesia
  • muscle rigidity
  • increased saliva
  • increased body temperature
  • irregular heartbeat
  • anaesthesia—reduced physical sensations with increased risk of injury
  • convulsions
  • coma
  • "near death" experiences.

Coming down

As the effects of ketamine begin to wear off, a person may experience a range of effects. These effects can last for approximately 24 hours and can include:

  • memory loss
  • impaired judgement
  • poor coordination
  • general aches and pains
  • disorientation.

Long-term effects

The long-term effects of ketamine use on health can include:

  • headaches
  • flashbacks
  • loss of sense of smell (due to snorting)
  • reduced memory function and other impairments in thinking
  • personality and mood changes
  • depression
  • impaired concentration.

Other effects of ketamine use

Ketamine and social problems

All areas of a person's life can be affected by drug use.

  • Disagreements and frustration over drug use can cause family arguments and affect personal relationships.
  • Legal and health problems can also add to the strain on personal, financial and work relationships.

Taking ketamine with other drugs

The effects of mixing ketamine with other drugs, including alcohol, prescription medications and over-the-counter medicines, are often unpredictable.

The dissociative effects of ketamine can make a person less aware of the effects of other drugs, such as the depressant effects of alcohol and opiates. Mixing ketamine and depressants can cause nausea, vomiting, decreased breathing rate, coma and death.

Combining ketamine with alcohol can result in a person vomiting, falling asleep or collapsing, which can result in them choking on their own vomit.

Using stimulant drugs such as amphetamines, ecstasy and cocaine with ketamine can further increase the heat rate and place the body under extreme stress.

Pregnancy and breastfeeding

Read about the effects of taking drugs during pregnancy or breastfeeding.


It is dangerous to drive after using ketamine. The effects of ketamine, such as impaired motor coordination, blurred vision and distorted perception, can affect driving ability.

People with distorted perception may be less aware of reality, which can increase the chances of an accident. The symptoms of coming down and withdrawal can also affect a person’s ability to drive safely.

Read more about the effects of drugs on driving.

Ketamine use in the workplace

Under occupational health and safety legislation, all employees have a responsibility to make sure they look after their own and their co-workers' safety. The effects of ketamine such as distorted perception and impaired motor coordination can affect a person’s ability to work safely and effectively. The symptoms of coming down and withdrawal can also affect a person’s ability to work safely and effectively.

Tolerance and dependence

There is evidence that after frequent and prolonged use, ketamine is addictive. People who use ketamine regularly can develop dependence and tolerance to it, which means they need to take larger amounts of ketamine to get the same effect.

Dependence on ketamine can be psychological, physical, or both. People who are dependent on ketamine find that using the drug becomes far more important than other activities in their life. They crave the drug and find it very difficult to stop using it.

People who are psychologically dependent on ketamine may find they feel an urge to use it when they are in specific surroundings or socialising with friends.

Physical dependence occurs when a person's body adapts to ketamine and gets used to functioning with the ketamine present.


If a dependent person stops taking ketamine, they may experience withdrawal symptoms because their body has to get used to functioning without it. People may experience withdrawal symptoms for approximately 4–5 days.

Withdrawal symptoms that may be experienced include:

  • chills
  • intense cravings
  • restlessness
  • nightmares
  • anxiety
  • tremors
  • sweating
  • irregular and rapid beating of the heart
  • depression
  • tiredness
  • decreased appetite.

Getting help


In Australia, there are many different types of treatments for drug problems. Some aim to help a person to stop using a drug, while others aim to reduce the risks and harm related to their drug use.

Find out more about treatment.

What to do if you are concerned about someone's amphetamine use

If you are concerned about someone's drug use, there is help available. Contact the alcohol and drug information service in your state or territory.

What to do in a crisis

Always call triple zero (000) if a drug overdose is known or suspected—and remember that paramedics are not obliged to involve the police.

If someone overdoses or has an adverse reaction while using ketamine, it is very important that they receive professional help as soon as possible. A quick response can save their life.

Visit the Better Health Channel to read St John Ambulance’s advice on drug overdose.

Ketamine use in Australia


According to the National Drug Strategy Household Survey, in 2010, 1.4% of Australians aged over 14 years had used ketamine at some stage in their life.

For more statistics about the use of ketamine in Australia, visit our Quick statistics page.

Is it legal?

Legally produced ketamine is a restricted substance and only a doctor or vet may prescribe or administer it. All other ketamine is illegal in Australia.

Read more about ketamine and Australian law.

For legal advice specific to your situation contact a legal aid service in your state or territory.

National drug policy

Australia’s national drug policy is based on harm minimisation. Strategies to minimise harm include encouraging people to avoid using a drug through to helping people to reduce the risk of harm if they do use a drug. It aims to reduce all types of drug-related harm to both the individual and the community.