Clozapine and alcohol - The risks
This page gives information on the potential risks of drinking alcohol if you are taking the medication clozapine. This information is for people who take clozapine in England. It is also for their carers, friends, and relatives.
What are the key points?
- Clozapine is an antipsychotic medication. It is used to treat the symptoms of schizophrenia and other psychosis related conditions.
- Clozapine and alcohol together can cause your nervous system to slow down, which can be dangerous. Sometimes, life-threatening.
- If you get symptoms of central nervous system depression, get immediate medical help.
- If you are prescribed clozapine, discuss alcohol use with your healthcare professional.
- Alcohol can affect clozapine and other antipsychotics in other ways.
- There can be other risks when taking clozapine.
- If you take antipsychotics, you should be offered regular physical health checks.
What is clozapine?
Clozapine is an antipsychotic medication.
Antipsychotic medications are mainly used to treat the symptoms of schizophrenia and other psychosis related conditions.
Clozapine can also be known by its trade names of Clozaril, Denzapine, and Zaponex.
Clozapine is usually given to people who are treatment resistant. This means other medication has not helped reduce or control symptoms well enough.
You should only be offered Clozapine after having tried 2 other antipsychotics.
See the following links for our information on:
Why can alcohol use and clozapine be risky?
If you take clozapine, drinking alcohol can be risky.
The NHS says:
- there are risks when drinking alcohol while taking clozapine,
- it can cause central nervous system depression, which can cause the brain and nervous system to slow down, and
- if the central nervous system slows down too much, it can be life-threatening.
The NHS specialist pharmacy service says if you take clozapine you should be made aware of this risk.
The British National Formulary (BNF) is a UK medications guide used by psychiatrists and other healthcare professionals in the NHS.
The BNF has an online guide on clozapine interactions here
The BNF online guide also warns of the risk of central nervous system depression caused by alcohol and clozapine. It says the risks could range from sedation to unconsciousness, coma, respiratory depression, and cardiovascular depression.
Sedation means being very sleepy or relaxed. Respiratory depression means when you breathe too slowly or too shallowly. Cardiovascular depression means a reduction in your heart rate.
It is very important you:
- discuss alcohol use with your healthcare professional, and
- carefully read your medication patient information leaflet to see what it says about alcohol use. The box your medication comes in should include the patient information leaflet. See below for how you can get a copy of the leaflet.
The symptoms of central nervous system depression are:
- Over sedated or inappropriately sleepy.
- Unusually confused or forgetful.
- Un-coordinated, with slurred speech, slow reflexes or difficulty moving.
- Breathing unusually slowly or have other breathing difficulties.
- A slow pulse or heart rate.
- A dry mouth.
- Blue lips.
- Clammy, cold skin.
You should get help straight away by calling 999 if you or a loved one show signs of the symptoms above.
How else can alcohol affect clozapine and other antipsychotics?
Alcohol can affect clozapine and other antipsychotics in other ways. So, you should:
- discuss with your healthcare professional how alcohol use can affect you if you take antipsychotics, and
- carefully read your medication patient information leaflet to see what it says about alcohol use. The box your medication comes in should include the patient information leaflet. See below for how you can get a copy of the leaflet.
Drinking alcohol with antipsychotics might increase the sedative effects. This means you might feel very tired.
Alcohol can cause sedation, which might affect your ability to:
- drive, even if you are under the legal limit, or
- do skilled tasks, like operate machinery.
You can talk to your healthcare professional about these things.
You can see our information on Driving and mental illness
Are there other risks when taking clozapine?
Is there a risk my white blood cell number will drop?
The main risk is clozapine can cause your white blood cell numbers to drop.
Drops in white blood cells can lead to infections. You will need regular blood tests to make sure your white blood cell count is healthy.
Your health professional should invite you to have blood tests. You will need:
- weekly blood tests for the first 18 weeks, then
- for the next year, you will need blood tests every 2-weeks, then,
- blood test should be done once a month.
You will be asked to stop taking clozapine if your white blood cell numbers start dropping.
You will have another blood test after you have stopped clozapine to make sure they are back to normal.
What about other side effects?
Clozapine can also cause other side effects. Common ones including pooling of saliva in the mouth, weight gain, severe constipation, and a fast heartbeat.
You can read about possible side effects in the patient information leaflet or ask your healthcare professional about them.
See the following links for our information on:
How can I get a copy of the patient information leaflet for my medication?
You can get a copy of the patient information leaflet for you medication online.
You can do this by visiting the Medicines and Healthcare Products Regulatory Agency (MHRA) website.
Be sure to search for exactly the right type of medication. There might be a number of different variations of the same type of medication.
Who can I speak to if I have questions about my medication?
- your psychiatrist,
- your GP, or
- a pharmacist.
Should I get physical health checks?
If you take antipsychotics, you should be offered regular physical health checks for certain things.
This is because antipsychotics can cause risks and side effects, like weight gain.
If you are not getting these regular physical health checks, you can speak to your GP.
AT the links below you can read our information on:
Who can help me if I am detained under the Mental Health Act or on a CTO?
If you take clozapine, you might be detained under the Mental Health Act or be on a community treatment order (CTO).
You can get help from an independent mental health advocate (IMHA) if:
- you are on a CTO, or
- if you are detained under most sections of the Mental Health Act.
An IMHA can help you understand:
- any medical treatment you are receiving, and the reasons for that treatment,
- your rights under the Mental Health Act, including your discharge rights,
- your rights and your conditions under your CTO, if applicable,
- the rights that other people have, such as your family,
- the parts of the Mental health Act that affect you, and
- any conditions or restrictions which affect you.
If you are in hospital under the Mental Health Act and would like to see an IMHA, you can ask a member of staff.
If you are on a CTO and would like to see an IMHA you can speak to:
- your care co-ordinator,
- your responsible clinician, or
- someone at your mental health team.
At the links below can read our information on:
Where can I get help for alcohol issues?
If you need help for alcohol issues you can see your GP, or these organisations might be useful:
- The Forward Trust. Help for drug or alcohol issues. Call 020 3981 5525.
- Drinkline. National alcohol helpline. Call 0300 123 1110.
- Alcoholics Anonymous. Help and support for dependent drinkers. Call 0800 917 7650.
- Turning point. Drugs and alcohol support.
- We Are With You. Delivers drug and alcohol services in the community.
At the links below you can find out more about:
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© Rethink Mental Illness 2025
First published January 2025
Next update January 2026, subject to any changes
Version number 1