clozapine (Clozaril, Fazacio ODT, Versacloz)

  • Pharmacy Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

Coping With Schizophrenia

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?

GENERIC AVAILABLE: Yes

Do I need a prescription for clozapine?

Yes

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.

Quick GuideSchizophrenia: Symptoms, Types, Causes, Treatment

Schizophrenia: Symptoms, Types, Causes, Treatment

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).

REFERENCE: FDA Prescribing Information

Last Editorial Review: 12/28/2015

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See more info: clozapine on RxList
Reviewed on 12/28/2015
References
REFERENCE: FDA Prescribing Information

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