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Antipsychotics

Explains what antipsychotics are used for, how the medication works, possible side effects and information about withdrawal.

How to take antipsychotics safely

This page has information about taking antipsychotics safely, including what to think about before you start taking them. It covers:

These pages may also help:

You can also discuss any concerns you have about taking antipsychotics with your doctor or psychiatrist.

Before you take any medication

Before you decide to take any medication, you should make sure you have all the facts you need to feel confident about your decision. See our pages on:

What tests do I need before taking an antipsychotic?

Before you start taking an antipsychotic, your doctor should do the following tests to assess your physical health:

Physical examination

This will include taking some physical measurements and asking some questions about your health and lifestyle, to find out:

  • your weight
  • your waist size
  • your blood pressure and pulse rate
  • your diet and level of physical activity
  • whether you show any signs of movement disorders
  • whether or not you smoke cigarettes
  • any other prescribed medicines you take, and any other drugs or substances you may take.

Blood tests

These are to measure your:

ECG 

An electrocardiogram (ECG) is a test used to check your heart’s rhythm and electrical activity. You should only need to have an ECG before being prescribed antipsychotics if:

  • you have high blood pressure or any other symptom that may relate to your heart
  • you have a family history of heart problems
  • you're going to be admitted to stay in hospital
  • an ECG is recommended for the specific drug that you may be prescribed.

Will I need more tests after I start taking antipsychotics?

After you start taking the medication, your mental health team will need to continue to monitor your physical health. They will also need to monitor and record:

  • whether you're taking your medication in the way you're supposed to
  • whether your medication is helping you
  • what side effects it's causing. This includes any side effects similar to the symptoms of psychosis, such as agitation.

If you're on a high dose of antipsychotics, you should be given an ECG every one to three months. This is because antipsychotics can sometimes cause heart problems as a side effect. The risk of this happening is greater with higher doses.

If you have unexplained blackouts, you should let your mental health team know so they can regularly monitor your heart rhythm. You should do this even if you’re on a low dose.

If you've been taking the drug for a year and are getting on well with it, your doctor can monitor your physical health instead of your mental health team. Your doctor should review your treatment at least once a year to check that it's still working well for you. But you can ask them for a review whenever you want one.

What if I have a medical condition?

If you have any of the following conditions, your doctor should take care when prescribing you an antipsychotic:

  • liver or kidney disease
  • cardiovascular (heart and circulatory) disease, or a family history of it
  • diabetes, or a family history of it
  • Parkinson’s disease
  • epilepsy
  • depression
  • myasthenia gravis (a rare disease affecting nerves and muscles)
  • an enlarged prostate
  • glaucoma (a serious eye disease)
  • lung disease with breathing problems
  • certain blood disorders.

If you have any medical condition at all, make sure that you tell your doctor or psychiatrist before they prescribe your medication. This includes any health conditions which aren't included in the list above. Your doctor may need to monitor you even more regularly to the effects of the antipsychotic on your health.

In some cases, it may not be safe to prescribe you an antipsychotic. For example, you should never be given an antipsychotic if:

  • you have phaeochromocytoma (a type of tumour causing very high blood pressure)
  • you are semi-conscious, unconscious or in a coma.

What if I'm an older person?

If you're an older person, your doctor or psychiatrist should take care when prescribing you an antipsychotic. If they do prescribe an antipsychotic, they may need to change the dosage of your medication. This is because:

  • antipsychotics are more likely to cause your blood pressure to drop when you stand up, which may cause you to fall
  • antipsychotics are more likely to cause both high and low body temperature
  • as you get older your body becomes less efficient at dealing with drugs. This means higher doses will have more risks of problems, so you are likely to need a smaller dose.

Could antipsychotics interact with other drugs?

If you take antipsychotics with other drugs, they can sometimes interact with each other. This can cause unpleasant or dangerous effects. You should always speak to your doctor, psychiatrist or pharmacist before taking any drugs at the same time or close together.

The information below shows the main interaction risks between antipsychotics and:

All drugs with antimuscarinic properties

All antipsychotics can cause antimuscarinic side effects. Combining them with other drugs that also have antimuscarinic effects is likely to make these side effects worse.

This is especially likely if you take antipsychotics with tricyclic antidepressants.

Anti-Parkinson’s drugs can also be antimuscarinic. It's possible that an anti-Parkinson's drug could interact with your antipsychotic to make you delirious. This may be confused with your psychotic symptoms.

Certain sleeping pills and minor tranquillisers

Some sleeping pills and minor tranquillisers can increase the sedative action of all antipsychotics. This means they will make you feel even more drowsy.

This is especially likely if you take an antipsychotic with:

Carbamazepine

Carbamazepine is an anticonvulsant drug, which is also used as a mood stabiliser. Taking it with antipsychotics can increase the risk that you will experience unpleasant side effects.

It can also make your body process certain antipsychotics faster. This makes them less effective. The antipsychotics affected by this are:

  • aripiprazole
  • cariprazine
  • clozapine
  • haloperidol
  • lurasidone
  • olanzapine
  • paliperidone
  • quetiapine
  • risperidone.

Lithium

Lithium is a type of mood stabiliser. Taking it with antipsychotics can increase the risk of:

  • serious blood disorders, especially with clozapine
  • neuromuscular side effects, if you are taking flupentixol, sulpiride, haloperidol or risperidone
  • neurotoxicity, which is a poisonous effect on the nervous system.

If your doctor or psychiatrist decides to prescribe an antipsychotic alongside lithium, they should start it at a lower dose than usual.

Tricyclic antidepressants

Taking tricyclic antidepressants with antipsychotics can increase the risk of disturbing your heart rhythm. This is especially likely with these antipsychotics:

  • fluphenazine
  • haloperidol
  • risperidone
  • sulpiride.

Trazodone

Trazodone is a type of antidepressant. Taking it with certain antipsychotics can increase the risk of:

  • experiencing severe side effects
  • disturbing your heart rhythm
  • experiencing a sudden drop in blood pressure when you stand up.

Over-the-counter drugs

Speak to your doctor, psychiatrist or a pharmacist before taking over-to-counter medicine with your antipsychotic. This includes complementary or alternative medicines. They will be able to tell you about any potential risks with taking the drugs together.

Alcohol and recreational drugs

  • Drinking alcohol can increase the sedative effect of antipsychotics. This means it will make you feel even more drowsy. You can ask your doctor, psychiatrist or pharmacist whether it’s safe to drink with the medication you've been prescribed. They can help you understand where to limit your alcohol intake.
  • If you take certain recreational drugs with antipsychotics, they may interact with each other. For example, taking amphetamines and chlorpromazine together can reduce their effects.

See our pages on recreational drugs and alcohol for more information about how these can affect your mental health. You can also visit the FRANK website for confidential advice on recreational drugs.

This information was published in September 2020. We will revise it in 2023.

References and bibliography available on request.

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