(Science: pharmacology) a drug that is effective in the treatment of psychosis.
antipsychotic drugs (also called neuroleptic drugs and major tranquillisers) are a chemically diverse (including phenothiazines, thioxanthenes, butyrophenones, dibenzoxazepines, dibenzodiazepines and diphenylbutylpiperidines) but pharmacologically similar class of drugs used to treat schizophrenic, paranoid, schizoaffective and other psychotic disorders, acute delirium and dementia and manic episodes (during induction of lithium therapy), to control the movement disorders associated with huntington disease, Gilles de la Tourette’s syndrome and ballismus and to treat intractable hiccups and severe nausea and vomiting.
antipsychotic agents bind to dopamine, histamine, muscarinic cholinergic, a adrenergic and serotonin receptors. Blockade of dopaminergic transmission in various areas is thought to be responsible for their major effects: antipsychotic action by blockade in the mesolimbic and mesocortical areas, extrapyramidal side effects (dystonia, akathisia, parkinsonism and tardive dyskinesia) by blockade in the basal ganglia and antiemetic effects by blockade in the chemoreceptor trigger zone of the medulla.
sedation and autonomic side effects (orthostatic hypotension, blurred vision, dry mouth, nasal congestion and constipation) are caused by blockade of histamine, cholinergic and adrenergic receptors.