antipsychotic

describing a group of drugs used to treat severe mental disorders (psychoses), including schizophrenia and mania; some are administered in small doses to relieve anxiety. Formerly known as major tranquillizers, antipsychotic drugs include the PHENOTHIAZINES (e.g. CHLORPROMAZINE ), BUTYROPHENONE (e.g. HALOPERIDOL ), and thioxanthenes (e.g. FLUPENTIXOL ). The atypical antipsychotics are a group of more recently developed drugs that may be helpful in those who do not respond to treatment with other antipsychotics. They include CLOZAPINE , RISPERIDONE , olanzapine (Zyprexa), and quietapine (Seroquel). Side-effects of many antipsychotics at high doses include abnormal involuntary movements.