Why is this drug prescribed?

Clozaril tablets contain the active ingredient clozapine, which is a type of drug known as an atypical antipsychotic. It works in the brain, where it affects a neurotransmitter called dopamine. Neurotransmitters are chemicals that are stored in nerve cells and are involved in transmitting messages between the nerve cells. Dopamine is a neurotransmitter known to be involved in regulating mood and behaviour, amongst other things. Schizophrenia is associated with an overactivity of dopamine in the brain, and this may be associated with the delusions and hallucinations that are a feature of this disease. Clozapine works by blocking the receptors in the brain that dopamine acts on. This prevents the excessive activity of dopamine and helps to control psychotic illness. Clozapine is restricted to treating schizophrenia in people who have not responded to, or are intolerant of, other treatments, as it can cause rare, but serious side effects. It is also used for treating psychotic illness in people with Parkinson's disease where other treatments have not worked. Clozapine is also sometimes used by specialists to treat episodes of mania in people with the psychiatric illness, bipolar affective disorder. This is an unlicensed use of the drug, and it is only used if other drugs have been ineffective at controlling the symptoms.

Treatments

* Schizophrenia in people for whom other antipsychotic drugs are ineffective or not tolerated * Psychotic disorders in people with Parkinson's disease, in cases where standard treatment has failed * Treatment of manic episodes resistant to standard treatment in bipolar affective disorder

What side effects can this drug cause?

* Decrease in the number of a type of white blood cell in the blood * Sudden severe deficiency in the number of white blood cells in the blood * Constipation * Dizziness * Drowsiness * Increased salivation * Increased heart rate * Headache * Blurred vision * Weight gain * A drop in blood pressure that occurs when going from lying down to sitting or standing, which results in dizziness and lightheadedness * Nausea and vomiting * Abnormal movements of the hands, legs, face, neck and tongue, eg tremor, twitching, rigidity * Seizures * High blood glucose level * Blood clots in the blood vessels that may detach and travel in the circulation to another area of the body * Liver disorders * Difficulty or pain when swallowing * High temperature combined with falling levels of consciousness, paleness, sweating and a fast heart beat. Requires stopping the drug and immediate medical treatment. * Inflammation of the muscular walls of the heart * Slow, shallow breathing