All drug use has risks. This page is for information only and does not constitute or replace medical advice. If you have medical concerns about your drug use, please speak to a medical professional.
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Ketamine is used as an anaesthetic in human and veterinarian medicine.

Other names

ket, special K, K


Off-white or brown crystalline powder or clear, odourless liquid

Drugs Wheel Category



Misuse of Drugs Act (1971) – Class B.

If prepared for injection ketamine becomes a class A drug
Penalties for possession are up to five years in prison and/or an unlimited fine. Penalties for supply are up to 14 years in prison and/or an unlimited fine.

How it’s taken

Most commonly snorted, it can also be swallowed in a cigarette paper (bombed). It may be injected into a muscle but this is strongly discouraged. Injecting ketamine does not reduce risk to the bladder and increases risk of blood-borne viruses, infection and overdose.


People using ketamine have reported the following dose/duration of effects, but this cannot be taken as a recommendation: duration and effects of any drug will depend on purity, regularity of use, other medications or drugs you have taken, your body and the route of administration.

An average dose for snorting is 15-30 milligrams and will give around 30 lines from a gram. The effects of ketamine are dose dependant — the higher the dose the more “dissociative” the effects and the stronger the effects on balance and coordination. Keeping doses low will avoid tolerance to ketamine which can build up quickly.

General information on dosing.


The onset of effects of ketamine, when snorted, will be felt within 5-10 minutes and the effects can last for 1–2 hours.  If swallowed the effects can be felt within 20 minutes and may last for up to 3 hours. After effects may be felt for up to 3 hours.

Ketamine can slow down messages from your body to your brain, make you feel detached from your surroundings and change your perception of time. Low doses taken in a club can be stimulating with increased energy and a pleasant high whereas taking it in a quiet, relaxed place with friends can be spiritual and calming. Higher doses tend to be trippy with people describing an out of body experience called a ‘K hole’. There is not set dose for a ‘K hole’ and it will vary between people depending on tolerance, body size, metabolism etc. Ketamine can affect your balance and coordination and frequent and/or long-term ketamine use can damage the bladder.


  • K-hole = dissociation or complete detachment. People k-holing may be unresponsive, tripping in their heads and unable to move
  • Bladder, urinary tract and liver problems: Prolonged use can result in permanent bladder damage – ‘K-bladder’
  • Damage to nose from snorting
  • Nausea and vomiting
  • Injury – it reduces your ability to feel pain
  • Ketamine mixed with a depressent, like alcohol, can slow down or stop your breathing to dangerous levels
  • Sleeping pills, benzos, heroin and GHB also increase the risk of slowing your breathing
  • Combining ketamine and alcohol can also affect your balance and perception of pain meaning you could be more likely to fall over and injure yourself.
  • Both drugs can also make you likely to throw up so anyone who has taken both should sleep on their side to prevent them choking on vomit in their sleep and should not be left alone
  • You may not realise how bad injuries are due to the pain-killing effect of ketamine
  • Mixing with alcohol, prescription medication or any other drugs risks unexpected, harmful and unpleasant effects, especially with psychedelic drugs or cannabis
  • If you are sick this could reduce the effectiveness of the contraceptive pill – use alternative methods to avoid unintended pregnancy

Harm reduction

If you choose to take ketamine then the following steps can help to reduce harm.
  • Remember that you cannot judge content or purity by appearance. Purity can vary, even with in batches – start low and go slow
  • Avoid mixing with alcohol, prescription medication or any other drugs, as the effects may be unexpected or harmful and unpleasant, especially with other psychedelics, cannabis or ketamine.
  • Drugs affect people differently and mixing different drugs can lead to unpredictable effects
  • Ketamine can affect your balance and coordination — only take in a safe space avoiding dangers such as glass tables or doors.
  • Tolerance to ketamine can build up quickly
  • Always let medical professionals know if you have a history of ketamine use if they are going to be administering anaesthetic or pain numbing drugs as ketamine tolerance can have an impact on how effective these are
  • Ketamine slows down your central nervous system and slows your breathing — with high amounts of ketamine this could mean someone’s breathing slows so much that it stops.
  • Ketamine can make you feel sick — ensure anyone who has been taking ketamine sleeps on their side to prevent choking should they throw up in their sleep. Mixing ketamine with alcohol can increase the risk of being sick
  • Mixing ketamine with psychedelic drugs can lead to more intense experiences which could be overwhelming
  • Mixing ketamine with cocaine can increase the risk to your heart. Cocaine can dull the effects of ketamine which could cause you take more to get the desired effect. This won’t improve your experience but will increase the risk to health
  • Ketamine and alcohol is a risky combination as both can affect your coordination, perception of pain and can reduce your rate of breathing
  • Some people may use ketamine to manage feelings of anxiety but for others regular use can increase anxious thoughts and reduce their ability to deal with them
  • Ketamine might be used to block feelings of mental pain — it can then be difficult to break the cycle of re-dosing.
  • Ketamine can seriously and permanently damage your bladder – this happens because our bodies cannot fully process ketamine and what is left over can crystallise on the bladder causing scar tissue
  • Stay well hydrated – try drinking water rather than fizzy drinks or diluting juice as water is easier for your body to process
  • Avoid swallowing ketamine, spit out any residue collecting at the back of your throat after snorting and clean out nose after each session to reduce damage
  • Spitting “the drip” won’t prevent damage to your bladder but could help to reduce overall harm
  • If you feel any negative effects such as anxiety remember that these will pass – let a friend know and try changing environment if safe
  • Look after your pals and seek medical help as soon as possible if anyone falls unwell. Be honest about what you know they have taken

If snorting

  • Grind or crush substances finely before snorting.
  • Use a straw or paper as a ‘tooter/snorter’ rather than money and throw away after use.
  • Position the ‘tooter/snorter’ as high up the nostril as possible.
  • Use a different nostril each time
  • Rinse out your nose with clean water after each session.
  • Don’t share your ‘tooter/snorter’ with anyone else (this could spread viruses).
  • Vitamin E oil can reduce damage to nose if applied in a thin layer inside after cleaning, like you would lip balm.
  • Spit out any powder which collects at the back of your throat – this may reduce over all harm but is not thought to reduce harm to your bladder

If injecting

  • Injecting ketamine does not reduce risk to the bladder and increases risk of blood-borne viruses, infection and overdose.
  • Only use clean needles and supplies. Free, clean needles are available from injecting equipment programs (IEPs) alternatively they can be bought online.
  • Use a wider needle for injecting into muscle.
  • Follow good hygiene practice and wash injection sites (before and after).
  • Always filter your drugs.
  • Do not use citric acid or heat to dissolve substances.
  • Use a fresh needle each time; needles become blunt after one use.
  • Never share equipment (including needles, filters, containers, spoons and water).
  • Rotate injection sites.
  • Avoid injecting into the neck and groin.
  • Dispose of needles responsibly. These can be returned to an injecting equipment program (IEP).
  • Seek medical assistance if site becomes painful, tender or hot, or there is swelling for more than a few days.

Detection time

People taking ketamine have reported the following detection time, but this cannot be taken as a recommendation; detection of any drug will depend on purity, regularity of use, other medications or drugs you have taken, your body and how it’s taken.
  • 1–5 days in urine