Clozapine for schizophrenia
Examples
Generic Name Brand Name clozapine Clozaril Clozapine is approved in Canada for treating patients with schizophrenia who did not respond well to other treatments. However, your doctor will need special authorization to prescribe clozapine for schizophrenia symptoms, and special monitoring is needed when clozapine is used.
How It Works
Clozapine is a second-generation antipsychotic. It is believed to affect the way brain chemicals (neurotransmitters) work.
Why It Is Used
Clozapine is used to treat the symptoms of schizophrenia. It may be used when another medication cannot be used or has not been effective.
How Well It Works
Clozapine is an effective treatment for symptoms of schizophrenia and may reduce symptoms that have not been controlled by other medications. It may be more effective both in the short and long term than first-generation antipsychotic medications (such as haloperidol) for some people.1 It has not been proven more effective than atypical (second-generation) antipsychotics, such as risperidone.
Side Effects
New warnings about serious side effects of clozapine have recently been issued. Health Canada's Therapeutic Products Directorate (TPD) and the drug's manufacturer have strengthened warnings to include that a potentially fatal heart problem (myocarditis) may occur when a person takes clozapine. Also, there is evidence that taking clozapine may increase the risk of developing insulin resistance, diabetes, and hyperglycemia (high blood sugar).2 While clozapine is effective in treating the symptoms of schizophrenia, discuss the possibility of these serious side effects with your doctor before taking this medication.
The most common side effects of clozapine are:
- Sluggishness or sleepiness.
- Weight gain.
- Increased saliva production.
Other side effects include:
- Increased heartbeat.
- Lowered blood pressure.
- Fever.
- Seizures, but usually in those taking high doses.
A rare but potentially deadly side effect is agranulocytosis, a condition that causes reduced production of white blood cells. Weekly blood cell counts are required during the first 6 months of treatment with this medication, with subsequent monitoring every 2 weeks.3, 1 Closely monitoring white blood cell counts can lower your chances of having this side effect.
See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)
What To Think About
Those who have seizures, heart or blood vessel problems, or liver or kidney conditions probably should not take clozapine.
It is not known whether clozapine is safe for children, older adults, and nursing women.
Because clozapine does not have some of the bothersome side effects of the older antipsychotic medications, people with schizophrenia may be more likely to take it regularly.
Clozapine costs more than first-generation antipsychotic medications. Most treatment and medications for schizophrenia are covered by provincial and territorial health plans, but coverage for medications varies. If your medications are not fully covered, many pharmaceutical companies have programs for people who cannot afford the high cost of medication. Ask your health professional whether you qualify to receive free medication.
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| Author: | Douglas Dana Ralph Poore | Last Updated: June 13, 2006 |
| Medical Review: | Adam Husney, MD - Family Medicine Kathleen Romito, MD - Family Medicine Malin K. Clark, MD, FRCPC - Psychiatry Lisa S. Weinstock, MD - Psychiatry | |
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| Topic Contents | |
| Examples | |
| How It Works | |
| Why It Is Used | |
| How Well It Works | |
| Side Effects | |
| What To Think About | |
| References | |