Clozapine: Price, Dosage & Where to Buy

Clozapine is an atypical antipsychotic used to treat severely ill people with schizophrenia when standard antipsychotic treatment has not worked well enough. It requires a prescription in the United Kingdom, and its use involves blood tests before and during treatment because it can reduce the white blood cells that help protect against infection.

Clozapine belongs to the atypical antipsychotic group. Medicines in this group affect chemical messengers in the brain, including dopamine and serotonin. These messengers pass signals between nerve cells by attaching to receptors, which act like receiving points.

Antipsychotics change the activity of some of these receptors and alter how signals are passed. This can help reduce symptoms of psychosis. Their effects on other receptors can also contribute to unwanted effects such as sleepiness.

Clozapine is used for treatment-resistant schizophrenia. This means schizophrenia in severely ill people who have not responded well enough to standard antipsychotic treatment. Its use is limited to this group because of risks including a severe fall in infection-fighting white blood cells and seizures.

The label also lists reducing the risk of repeated suicidal behaviour in people with schizophrenia or schizoaffective disorder who are judged to have an ongoing risk. This assessment is based on their history and recent clinical condition. Here, suicidal behaviour means actions that put a person at risk of death.

The label lists oral suspension at 50 mg/mL and oral tablets at 25 mg, 50 mg, 100 mg and 200 mg. The label lists orally disintegrating tablets at 12.5 mg, 25 mg, 100 mg, 150 mg and 200 mg. The usual starting dose is 12.5 mg once daily or twice daily.

The label lists increases of 25 mg to 50 mg per day, if well tolerated, towards a target of 150 mg to 225 mg twice per day by the end of two weeks. The label lists later increases of up to 100 mg once or twice weekly and a maximum of 450 mg twice daily. Gradual increases are intended to reduce the risk of low blood pressure, slow heartbeat and fainting.

The suspension may be used with or without food. Blood test results, treatment interruptions, interacting medicines, and kidney or liver impairment may require changes to the prescribed regimen.

The oral suspension is stored at 20°C to 25°C, with excursions permitted between 15°C to 30°C. It must not be refrigerated or frozen and must be protected from light.

The suspension is stable for 100 days after the bottle is first opened. Keep out of reach of children.

A missed dose or break in clozapine treatment can affect how safely treatment is restarted. Even a brief interruption can increase the risk of low blood pressure, slow heartbeat and fainting when treatment resumes.

Contact the prescribing team or pharmacist for advice before restarting after a break. Do not double a dose to make up for a missed dose.

Published pregnancy studies have not established a clozapine-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. Exposure during the third trimester can cause movement problems or withdrawal symptoms in newborn babies, including tremor, sleepiness, breathing problems and feeding difficulties. Untreated schizophrenia also carries risks during pregnancy.

Clozapine is present in human milk. Sleepiness and a severe reduction in white blood cells have been reported in exposed infants.

Breastfeeding benefits, the mother's treatment needs and possible risks to the infant should be considered together. Exposed infants need monitoring for excessive sleepiness and low infection-fighting white blood cells.