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: 

  • What tests do I need before taking an antipsychotic? 
  • What if I have a medical condition? 
  • What if I’m an older person? 
  • Could antipsychotics interact with other drugs?

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 you should know before taking any psychiatric drug 

receiving the right medication for you 

your right to refuse medication

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:

  • blood sugar 
  • haemoglobin (red blood cells) 
  • cholesterol (blood fats) 
  • prolactin level. 


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 are recommended to have regular ECG.  This is because antipsychotics can sometimes cause heart problems as a side effect. The risk of this  happening is greater with higher doses. 

What if I have a medical condition? 

If you have any of the following conditions, your doctor should take extra 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 extra 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 
  • certain sleeping pills and minor tranquillisers 
  • carbamazepine 
  • lithium 
  • tricyclic antidepressants 
  • trazodone 
  • over-the-counter drugs 
  • alcohol and recreational drugs 

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: 

  • the minor tranquillisers used for anxiety, which are buspirone, pregabalin
  • the ‘Z’ drugs, which are zolpidem and zopiclone. 


Carbamazepine is an anticonvulsant drug, which  can also sometimes be 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 
  • clozapine 
  • haloperidol 
  • lurasidone 
  • olanzapine 
  • paliperidone 
  • quetiapine


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, or haloperidol
  • 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 
  • sulpiride. 


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-the-counter medicine with your  antipsychotic. This includes complementary or alternative medicines e.g Traditional Chinese 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 effects 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. 

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