Indications: schizophrenia (including psychosis in Parkinson's disease) in patients unresponsive to, or intolerant of, conventional antipsychotic drugs.

Cautions: cardiovascular disease; history of epilepsy; accompanied by strict procedures for the monitoring of white blood-cell counts for the first 18 weeks then at least fortnightly; bone-marrow; elderly; monitor leucocyte and differential blood counts; prostatic hypertrophy, susceptibility to angle-closure glaucoma; taper off other antipsychotics before starting; close medical supervision during initiation (risk of collapse because of hypotension); hepatic impairment; pregnancy. Clozapine should be used cautiously with drugs which cause constipation (e.g. antimuscarinic drugs) or in history of colonic disease or bowel surgery.

Contra-indications: severe cardiac disorders (e.g. myocarditis); severe renal impairment; history of neutropenia or agranulocytosis; bone-marrow disorders; paralytic ileus; alcoholic and toxic psychoses; history of circulatory collapse; drug intoxication; coma or severe CNS depression; uncontrolled epilepsy; breast-feeding; history of concurrent use of co-trimoxazole, chloramphenicol, sulphonamides, penicillamine, carbamazepine or anti neoplastics with high bone marrow suppression risk.

Side Effects: sedation; antimuscarinic symptoms; extra pyramidal symptoms; neutropenia and potentially fatal agranulocytosis; headache; dizziness, hyper salivation, urinary incontinence, priapism, pericarditis, myocarditis, and delirium; nausea and vomiting; hyperglycemia, hypertension; rarely circulatory collapse.

Dose: under close medical supervision on first day, 12.5 mg once or twice.

On second day, 25-50 mg; then slowly increased if well tolerated by 25-50mg over 2-3 weeks to 300 mg daily in divided doses.

The larger dose (up to 200 mg as single dose daily) is taken at bed time.

If necessary, the dose may be increased by 50-100 mg once or twice weekly to a max. of 900 mg daily.

Usual antipsychotic dose, 200-450 mg daily. Subsequent adjustment to the usual maintenance dose of 150-300mg.

Child, not recommended.

Elderly and special risk group, first day, 12.5 mg once. Subsequent adjustment restricted to 25mg daily in slow and small steps in case of epileptic seizures, suspend for 24 hours and resume at lower dose.

Restarting the treatment after interval of more than 2 days, 12.5mg once or twice on first day and could be increased more quickly than initial therapy.