Clozapine is an antipsychotic medication. It works by changing the actions of chemicals in the brain. Clozapine is used to treat severe schizophrenia, or to reduce the risk of suicidal behavior in people with schizophrenia or similar disorders. Clozapine is available only from a certified pharmacy under a special program. You must be registered in the program and agree to undergo frequent blood tests. Clozapine may also be used for purposes not listed in this medication guide.