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Mental Health

Help for Treatment Resistant Psychosis


Information on clozapine and other options

Author: BC Schizophrenia Society


What is treatment resistant psychosis?

Patients with schizophrenia or schizoaffective disorders who have not responded well to trials of at least two other antipsychotic medications, are considered to have ‘treatment resistant’ psychosis.

What is clozapine?

Clozapine is a medication that can be very effective for people whose schizophrenia has not responded well to other medications. It is used to treat symptoms such as hallucinations and delusions.

For many people, clozapine can be a very effective treatment, and can make a huge difference to their quality of life. As well, clozapine has been shown to greatly reduce the risk of suicide in persons with schizophrenia.

People taking clozapine must have weekly blood tests when they first start treatment. This is to ensure that they don’t develop a rare but serious side effect that causes problems with white blood cells, which are needed to fight infection.

After taking the medication regularly, blood tests are generally less frequent, reduced to every two weeks, then every four weeks.


How is clozapine taken?

Clozapine comes in tablet form and must be taken as prescribed by the treating physician. Clozapine must be taken regularly to prevent psychotic symptoms from occurring again. If there are any concerns about continuing the medication as prescribed, they should be discussed immediately with the doctor.

If someone forgets to take their medication, it should be taken as soon as possible—provided this is within a few hours of the usual time. Otherwise, it is better to wait until the next dose is due and then take only the usual amount. In other words, patients should not try to “catch up” by doubling the amount of a missed dose.

If clozapine is not taken for more than two days, the doctor should be contacted immediately. The regular clozapine dose should not be started again without consulting the doctor.


Clozapine should not be stopped suddenly

Stopping clozapine suddenly can put a person at risk for a rebound psychosis that may be even worse than previous episodes of illness.


What else should we know?

  • Clozapine can increase the effects of alcohol, so a person may become more intoxicated or sedated if using alcohol with clozapine

  • Clozapine can cause drowsiness or slow reflexes so patients should not drive if they experience these effects.

  • Cigarette smoking can affect levels of clozapine in the bloodstream, so it is important to let the doctor know about changes in smoking habits.

  • The doctor should be informed about any other medication the patient is taking, including natural remedies and non-prescription drugs.

  • Make sure the doctor or pharmacist is told as soon as possible if the patient is not feeling well while taking clozapine.


Monitoring for side effects

Talk to the doctor about treatment for any side effects that may occur such as sedation, weight gain, high temperature or ‘flu-like’ symptoms, dizziness, increased saliva, constipation, or nausea.


Questions to ask the psychiatrist

  1. What is refractory psychosis (also called treatment resistant psychosis)?

  2. What is the best evidence-based treatment for treatment resistant psychosis?

  3. What are the benefits of antipsychotic medication?

  4. What are the risks of a person with psychosis taking too many different medications (polypharmacy)?

  5. What are the advantages and risks of clozapine?

  6. How is clozapine use monitored and managed?

  7. How are medication switches best managed?

  8. What are the risks of stopping taking antipsychotic medication?

  9. What are some strategies to deal with not wanting to take antipsychotic medication?

This brochure contains general information and does not include all possible side effects or brand names of any medications


About the author

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The BC Schizophrenia Society helps individuals and families find their way in the mental health system. They also provide regional programs and services to help people with serious mental illnesses and their families. For more, visit or call 1-888-888-0029.


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