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Reducing risks from ketamine - Ketamine

It’s always safest not to take drugs.

You can never be sure of the strength or content of drugs. Drugs sold as ketamine may contain other drugs.

Higher doses of ketamine can make you feel disconnected from your body and cause hallucinations.

Ways to reduce risks from ketamine

There are ways to reduce the risk of harm if you use ketamine. Select a piece of advice to find out more.

Consider if there is extra risk for you - such as health conditions or how you feel.

There are always risks if you use drugs. But some people may be more at risk than others.

If you or someone in your family has any health conditions or mental health difficulties, you may be more at risk of a drug emergency.

It can be hard to know your level of risk. Some people have health conditions and do not know it.

If you feel low, anxious or stressed, you are more at risk of a negative or challenging experience.

Be with people you trust - use a buddy system if possible.

Pick a meeting point and look out for each other. Do not use alone.

Prepare a plan with your buddy on what to do in case of an emergency.

This may be that you both agree to:

  • learn the signs of an overdose
  • call the emergency services
  • stay with the other person until help arrives
Wait at least 2 hours after eating before you use and sleep on your side.

This is to reduce the risk of choking on your vomit.

Ketamine can make you:

  • get sick (vomit)
  • feel drowsy or lose consciousness

If you are with someone who took ketamine, put them on their side.

Start with a small amount and wait 2 hours before you take more.

This is to reduce the risk of an overdose or drug emergency.

The contents or strength of drugs can vary, even in the same batch.

If you start with a small amount, you can:

  • see how you react
  • stop if you get an effect you did not expect or do not want

It can take up to 2 hours for some effects to happen. If you take too much too soon, it increases your risk.

Stay in a calm and safe place away from risks such as heights, roads or water.

This is to reduce the risk of accidents or injuries. Ketamine can affect your control of your body and make you less aware of your surroundings.

Noisy or busy places can cause an overwhelming experience. For example, at a club or festival.

Plan a safe way to get home. It is dangerous to drive if drugs are in your system. You could harm yourself or other people. A drug can still be in your system even if you do not feel the effects.

Keep track of what you use.

Only take with you what you intend to use. This can reduce the risk of taking too much in 1 session.

To keep track of what you use each session, you could:

  • set an alarm
  • note the time you use - for example, take a screenshot on your phone

Take breaks between use to reduce your risk of tolerance, mental health difficulties and bladder problems.

Make sure you get enough food and rest.

Consider less risky ways of using if you inject or put ketamine in drinks.

Injecting drugs increases the risk of overdose and can cause vein damage or infections.

How to reduce risks if you snort, smoke or inject drugs

Putting crushed pills or powders in drinks increases the risk of taking too much too soon. There is also a risk that someone else could drink them by mistake. Crush and dab a small amount of powder instead.

If you put powders in drinks, use a very small amount and check that the powder dissolves.

Sip water or sports drinks - but not more than 1 pint an hour.

This is to reduce the risk of dehydration and water intoxication. Ketamine can increase your body temperature, make you thirsty and stop you peeing.

But if you drink too much water, your body pushes the extra water into your cells. The extra water causes a salt imbalance and swelling in your brain cells.

Think about your sexual health.

Ketamine can reduce your inhibitions. There are things you can do to look after yourself and your partners if you could have sex when you take drugs.

Drugs and sex

Find safe ways to cope with comedowns or cramps.

Using drugs or alcohol to cope with comedowns can make you feel worse.

Try to:

  • get enough sleep or rest
  • eat well
  • keep in contact with friends and check if they are OK too
  • talk to someone you trust about how you feel if you had a negative experience or witnessed something that worries you
  • do some light activity, such as a walk - it releases chemicals in your brain that improve your mood (endorphins)
  • do some relaxation exercises to manage stress, anxiety and worry
  • take regular breaks from drugs and alcohol
  • get medical advice if you have thoughts or feelings that worry you

To relieve bladder pain and cramps you can:

  • do gentle stretches
  • go for a slow walk
  • drink water in small sips
  • use a heat pack instead of a bath

Ketamine can make you drowsy and tired. There is a risk of drowning if you take a bath too soon after using ketamine.

Avoid taking more ketamine, other drugs or putting someone in a bath.

Know what to do in case of a drug emergency.

If you take any kind of drug, it is important to know:

If you know what to do during a challenging experience, it could stop a situation getting worse and help you support someone. But it is always safest to get medical advice if someone has overwhelming or unexpected effects.

Getting help can prevent serious damage or death. Your wellbeing is the main priority.

Drug overdose and emergencies

Mixing ketamine with alcohol or other drugs

Only use 1 substance at a time. Using ketamine with alcohol, medicines or other drugs can have unpredictable and negative effects.

For example:

  • severe vomiting and risk of choking - if you take it with alcohol or antihistamines
  • stress on your heart or other organs - if you take it with stimulants such as MDMA
  • an overwhelming or challenging experience - if you take it with drugs that cause hallucinations such as LSD, 2CB or cannabis
  • problems breathing - if you take it with depressants such as benzodiazepines, opioids or G (GHB or GBL)

Mixing drugs is always more risky.

Cocaine and ketamine (CK)

The combination of cocaine and ketamine is sometimes called CK, CK1 or Calvin Klein. CK puts a lot of strain on your body.

The combination can cause more harmful effects than either drug alone.

Emergency action required: Call 112 or 999 if

you or someone has taken ketamine and has:

  • severe confusion
  • problems breathing
  • severe nausea or vomiting
  • a slow or irregular heartbeat
  • a seizure (fit)
  • cold and clammy skin - white skin may turn blue, black or brown skin may turn grey
  • lost consciousness - put them on their side or in the recovery position

Stay with the person until help arrives.

Tell the medics everything you know about the drug and give them any leftover drug if possible. It will help them decide the right treatment.

If you are worried about ketamine use

If you are worried about your own or someone else’s use, you can get support. This can be when ketamine use affects your health, relationships, work or other areas of your life.

Getting help for drug use

If you are worried about someone else

Non-urgent advice: Drugs and alcohol helpline

You can contact the helpline for support, information or advice on treatment and support options.

Freephone: 1800 459 459
Monday to Friday, 9.30am to 5.30pm

Email: helpline@hse.ie

Page last reviewed: 24/11/2025
Next review due: 24/11/2028