clozapine (Clozaril, Fazacio ODT, Versacloz)

What is clozapine, and how does it work (mechanism of action)?

Clozapine is an anti-psychotic medication that works by blocking receptors in the brain for several neurotransmitters (chemicals that nerves use to communicate with each other) including dopamine type 4 receptors, serotonin type 2 receptors, norepinephrine receptors, acetylcholine receptors, and histamine receptors. Unlike traditional anti-psychotic agents, such as chlorpromazine (Thorazine) and haloperidol (Haldol) as well as the newer anti-psychotics, risperidone (Risperdal) and olanzapine (Zyprexa), clozapine only weakly blocks dopamine type 2 receptors.

What brand names are available for clozapine?

Clozaril, FazaClo, Versacloz

Is clozapine available as a generic drug?


Do I need a prescription for clozapine?


What are the uses for clozapine?

Clozapine is a medication prescribed for the management of psychotic disorders such as schizophrenia.

What are the side effects of clozapine?

The most common side effect of clozapine is drowsiness.

Dizziness is another side effect of clozapine. Dizziness may occur in 1 of 5 persons taking clozapine. In some cases this may be due to orthostatic hypotension, a marked decrease in blood pressure that occurs when going from a lying or sitting position to a standing position. The drop in blood pressure may lead to loss of consciousness or even cardiac and respiratory arrest. This reaction is more common during the first few weeks of therapy while the dose is increasing, when drug is stopped briefly, or when patients are taking benzodiazepines such as diazepam (Valium) or other anti-psychotic drugs.

Seizures have occurred in approximately 1 of every 20 to 30 persons receiving clozapine. Patients receiving higher doses seem to be at higher risk.


Schizophrenia is the most disabling mental illness. See Answer

What is the dosage for clozapine?

Clozapine is given once, twice, or three times daily. The dose often is increased slowly until the optimal dose is found. The full effects of clozapine may not be seen until several weeks after treatment is begun.

Which drugs or supplements interact with clozapine?

Risperidone (Risperdal) may cause an increase in the amount of clozapine in the blood. This could lead to an increased risk of side effects from clozapine.

Is clozapine safe to take if I'm pregnant or breastfeeding?

There are no adequate studies of clozapine in pregnant women. Studies in animals suggest no important effects on the fetus. Clozapine can be used in pregnancy if the physician feels that it is necessary.

Animal studies suggest that clozapine is secreted in breast milk. Therefore, women taking clozapine should not nurse their infants.

What else should I know about clozapine?

What preparations of clozapine are available?

Tablets (orally disintegrating): 12.5, 25, 100, 150, and 200 mg

How should I keep clozapine stored?

Tablets should be kept below 30 C (86 F).


Clozapine (Clozaril, Fazacio ODT, Versacloz) is a medication prescribed for the management of psychotic disorders such as schizophrenia. Side effects, drug interactions, warnings and precautions, and pregnancy information should be reviewed prior to taking any medication.

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See more info: clozapine on RxList
Medically reviewed by John P. Cunha, DO, FACOEP; Board Certified Emergency Medicine


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