Clozapine may only be prescribed under the supervision of a psychiatrist. Dispensing is conditional on a satisfactory blood test confirming it is safe to proceed. Missing blood tests means treatment cannot safely continue.
What it treats
Which conditions is Clozapine used for?
Overview
What is Clozapine?
Clozapine is reserved for people whose schizophrenia has not responded adequately to at least two other antipsychotic medicines. In this specific situation, evidence consistently shows it to be more effective than any other option available.
It is also the only psychiatric medicine shown to meaningfully reduce the risk of suicide in people with schizophrenia, a significant and unique benefit.
Because clozapine can, in a small number of people, cause a serious reduction in white blood cells which are essential for fighting infection, blood tests are required on a strict schedule. This is not optional. Dispensing depends on those results.
How it works
What does it do in the brain?
Formulations in Kenya
How is it available?
Availability across Africa
Where is it available in Africa and what is it called?
| Country | Common Brand Name(s) | Notes |
|---|---|---|
| Kenya | Clozaril, generic | On KEML 2023 Level 5-6. Available at Mathari Hospital and specialist facilities. |
| South Africa | Clozaril, Denzapine, generic | On South Africa EML. Available through registered monitoring programmes. |
| Nigeria | Clozaril, generic | Available at specialist psychiatric facilities in Lagos and Abuja. |
| Zimbabwe | Generic clozapine | Available at Parirenyatwa Hospital psychiatric unit. |
| Uganda | Generic clozapine | Available at Butabika National Hospital. |
| Tanzania | Generic clozapine | Available at Muhimbili National Hospital psychiatric unit. |
| Ghana | Generic clozapine | Available at Accra Psychiatric Hospital. |
Side effects
What might you feel while taking it?
These are the most commonly reported effects. Not everyone experiences them, and many settle within the first few weeks.
- Pronounced sedation, especially early in treatment
- Excessive drooling, particularly at night
- Significant weight gain
- Constipation. This must be actively managed.
- Increased heart rate when starting treatment
- Increased urination or bladder control problems
- Fever, sore throat, or mouth ulcers while on clozapine must be reported to your doctor the same day. These may be signs of dangerously low white blood cells.
- Chest pain, shortness of breath, or unusual fatigue in the first two months. These may indicate heart inflammation.
- A seizure or fit. Tell your doctor immediately.
- Severe constipation that does not resolve with laxatives. Do not ignore it.
Risks
Important risks you should understand before taking this medicine
- Agranulocytosis: clozapine can cause the bone marrow to stop producing white blood cells in approximately 1 in 100 to 200 people. Without white blood cells you cannot fight infection, and this can be fatal. This is why the blood monitoring requirement exists and why it is non-negotiable.
- Myocarditis and cardiomyopathy: inflammation of the heart muscle can occur, usually in the first two months of treatment. Chest pain, breathlessness, or unusual fatigue in the first weeks of treatment should be reported to your doctor immediately.
- Severe constipation and bowel obstruction: clozapine slows bowel function significantly. Constipation that goes untreated can progress silently to a bowel obstruction, which can be fatal. Bowel management must be actively discussed and addressed at every appointment.
- Seizures: the risk of having a seizure increases substantially at higher doses of clozapine. Tell your doctor immediately if you have any fit or unusual episode.
- Smoking significantly and rapidly changes how clozapine works in the body. If you stop smoking while on clozapine, levels in the blood rise quickly. Your doctor must be informed immediately.
Who should not take it
Important warnings before starting
- A previous serious blood disorder caused by clozapine
- Current white blood cell count below the safe threshold
- Carbamazepine (must not be combined with clozapine)
- Severe liver, kidney, or heart disease
Special care needed
Situations that need extra attention
- Blood test results must be satisfactory for the medicine to be dispensed at every point in the monitoring schedule
- Constipation must be actively prevented from day one. Your doctor will advise on a bowel plan.
- Never stop clozapine suddenly
- Inform your doctor immediately if you start or stop smoking
If pregnancy is possible or planned, this must be discussed with your psychiatrist. Careful specialist planning is required.
Clozapine should not be taken while breastfeeding. Levels in breast milk are significant and pose a risk to the infant.
Other medicines
Medicines and substances that can interact with it
- Carbamazepine: Contraindicated. Both medicines affect blood cell production and the combination significantly increases risk.
- Fluvoxamine (an antidepressant): Can dramatically increase clozapine levels in the blood, risking toxicity. Only used under very careful specialist supervision.
- Smoking: Smoking speeds up the breakdown of clozapine. Quitting smoking raises levels rapidly. Your doctor must be informed immediately.
- Injectable benzodiazepines: Carries a risk of heart and breathing problems. Your treating team is aware of this.
Tests and follow-up
What your doctor will monitor
- White blood cell count must be checked weekly for the first 18 weeks, then fortnightly, then monthly. Dispensing is conditional on results.
- ECG and cardiac enzyme tests in the first two months to screen for heart inflammation
- Weight, blood sugar, and cholesterol at regular intervals
- Bowel function at every appointment. Do not normalise constipation.
- Blood clozapine levels when toxicity or poor response is suspected
Stopping this medicine
What happens if you stop taking it?
In Kenya
What you should know about this medicine in Kenya
Clozapine is available at Mathari National Teaching and Referral Hospital and select county and private specialist facilities in Kenya.
Many people in Kenya who qualify for clozapine remain on inadequate treatment because the diagnosis of treatment resistance has not been made, or because access to a monitored programme does not exist near them.
The blood monitoring requirement can feel burdensome for families, but understanding that it is what keeps the medicine safe helps sustain commitment to the schedule.
Sources
References
- Ministry of Health, Kenya. (2023). Kenya Essential Medicines List 2023. Nairobi: Ministry of Health.
- Ministry of Health, Kenya. (2023). Kenya National Medicines Formulary, 1st Edition. Nairobi: Ministry of Health.
- Meltzer, H. Y., et al. (2003). Clozapine treatment for suicidality in schizophrenia. Archives of General Psychiatry, 60(1), 82-91.
- Leucht, S., et al. (2013). Comparative efficacy and tolerability of 15 antipsychotic drugs. The Lancet, 382(9896), 951-962.
- World Health Organization. (2023). Model List of Essential Medicines, 23rd Edition. Geneva: WHO.