Clozaril (clozapine)
Clozaril (clozapine)
Brand name: Clozaril®
Active ingredient: Clozapine
Type: Atypical antipsychotic
Available from: Novartis Pharma Canada; HLS Therapeutics
Form: Oral tablets
Generic: AA‑Clozapine; Gen‑Clozapine
Listed on Ontario formulary: No — Special Drugs Program
OHIP+ coverage: No — Special Drugs Program
What is Clozaril used for?
Primarily used for treatment‑resistant schizophrenia (failure or intolerance to at least 2 other antipsychotics).
May be used for other psychiatric conditions based on prescriber judgment.
How should I take Clozaril?
May be taken with or without food.
Often taken at night due to sedation.
Doses above 500 mg/day are usually split.
Available in 25 mg and 100 mg tablets.
Most people take 300–450 mg/day; maximum is 900 mg/day unless otherwise directed.
Requires regular blood monitoring for white blood cell levels.
Common side effects
- Drowsiness
- Increased heart rate
- Constipation
- Weight gain
- Drooling (especially at night)
- Bed‑wetting (nocturnal enuresis)
- Orthostatic hypotension
Rare but serious side effects
- Dangerous drop in white blood cells (requires monitoring)
- Heart problems
- Seizures
- Diabetic ketoacidosis (DKA)
- Neuroleptic malignant syndrome (NMS)
Warnings/Precautions
Older adults with dementia‑related psychosis have an increased mortality risk with antipsychotics.
Smoking cigarettes reduces clozapine levels, requiring dose adjustments if smoking habits change.
Avoid alcohol and street drugs.
Medication interactions
Tell all providers you take Clozaril.
Interactions include:
- Diphenhydramine (Benadryl)
- Lorazepam, zopiclone
- Fentanyl
- Ciprofloxacin
- Carbamazepine
Smoking also interacts with Clozaril by lowering drug levels.