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8-minute read

Key facts

  • Ketamine is used by doctors and vets as a pain killer, sedative and sometimes to treat depression.
  • It’s also used illegally as a hallucinogen.
  • Ketamine causes users to feel happy and relaxed, but can also cause unwanted mental and physical effects.
  • Ketamine overdose can be fatal.
  • Stopping ketamine can be hard and you should speak to your doctor if you are struggling with withdrawal.

What is ketamine?

Ketamine is a medicine used by doctors and vets as a pain killer and a sedative. It stops your brain from interpreting pain messages. It’s being studied as a medicine for depression.

It’s also used illegally for its hallucinogenic ‘high’ effect. If bought illegally, it comes as a white powder that can be made into tablets or dissolved into a clear liquid.

Ketamine can be:

  • swallowed
  • snorted
  • injected
  • inserted anally (up your bottom)
  • smoked with cannabis or tobacco

Sometimes ketamine is sold as ecstasy. It’s sometimes used to spike people’s drinks.

Ketamine is also known as:

  • special K
  • K
  • ket
  • kitkat
  • super K
  • horse trank

What are the effects of taking ketamine?

Ketamine takes effect within 30 seconds to 20 minutes, depending on how it’s taken. Its effects can last for 45 minutes to 3 hours, and can include feeling happy and relaxed.

Ketamine users may also experience what is known as ‘falling into a k-hole’, where they feel unattached from their body.

People who take ketamine can also hallucinate, as it alters their perception of reality. They can see, hear, smell or taste things that don’t exist, or can perceive them differently to how they really are.

Ketamine may cause:

  • blurred vision
  • slurred speech
  • disorientation and drowsiness
  • feeling numb
  • feeling uncoordinated
  • loss of consciousness

Ketamine can also cause users to have unwanted side effects like:

Ketamine can affect people differently based on:

  • how much you take
  • how strong it is
  • your size, height and weight
  • whether you are used to taking it
  • whether you take other drugs at the same time

What can go wrong with ketamine?

People coming off ketamine may have symptoms for 4 to 6 days, including:

  • depression
  • clumsiness
  • memory loss
  • disorientation
  • aches and pains
  • feeling anxious and restless

‘Falling into a k-hole’ can also cause users to harm themselves while affected.

A ketamine overdose can cause:

These can be fatal (cause death).

Signs that someone has overdosed on ketamine include:

  • they can’t move
  • they have rigid muscles
  • they are convulsing
  • they are unconscious
  • their blood pressure is high

If you think someone has overdosed on ketamine, call triple zero (000) for an ambulance. Ambulance officers don’t have to call the police.

Can ketamine cause long-term problems?

People who use ketamine long-term can develop:

Ketamine bladder syndrome is a painful condition that involves ulcers in your bladder which causes incontinence. It needs long term treatment and can lead to kidney problems.

Regular users of ketamine are also more likely to have social, work and financial problems.

What if I use other drugs or alcohol together with ketamine?

Taking ketamine with alcohol, heroin or other opiates is dangerous. It can slow your nervous system and stop your body from functioning normally. This can be fatal (cause death).

Taking ketamine with other drugs also puts strain on your body and leads to a fast heart rate. These other drugs include:

Can I become dependent on ketamine?

People who use ketamine regularly can become tolerant — they need more of the drug to achieve the same effects.

It’s also possible to develop a dependence to ketamine. This is when you spend a lot of time thinking about the drug and trying to get it. Some users may feel like they need the drug just to get through the day.

Dependence can impact your life, work and relationships. You may find it difficult to stop using ketamine or to control how much you use. This is often due to withdrawal symptoms.

Withdrawal symptoms can include:

How can I stop using ketamine?

Getting off ketamine can be difficult. If you are struggling with withdrawal, speak to your doctor. They can help you manage withdrawal symptoms, and advise you on treatment options, such as:

Resources and support

See 'What are the effects of taking drugs?' on the Department of Health website for more information.

Find out more about how drugs and alcohol can impact your health, including where to find help and support.

You or someone you know may be finding it hard to manage issues related to drug use. You can try healthdirect’s Symptom Checker to get advice on when to seek professional help.

The Symptom Checker guides you to the next appropriate healthcare step for you. This could be:

  • self-care
  • talking to a health professional
  • going to a hospital
  • calling triple zero (000)

You can find support and more information about ketamine through:

Support for injection behaviour

If you inject ketamine, you can reduce your risk of blood-borne disease by attending a Needle and Syringe Program (NSP).

Needle and Syringe Programs provide clean needles or syringes to people who inject drugs. It’s sometimes referred to as ‘needle exchange’.

The types of Needle and Syringe Programs vary, from pharmacies to vending machines.

You can also find a local Needle and Syringe Program using the healthdirect Service Finder. Select ‘By name’ and type ‘needle’ into the search bar.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: April 2023

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