APA Dictionary of Psychology

n. the first synthesized antipsychotic agent, introduced into clinical use in Europe in 1952 and in Canada and the United States in 1954. It was initially used to reduce presurgical anxiety and deepen conscious sedation during surgical procedures; its antipsychotic effects were discovered serendipitously. This low-potency phenothiazine provided a degree of previously unavailable behavioral control and management of positive psychotic symptoms and ushered in the modern era of psychopharmacological treatment. However, although effective in managing the acute symptoms of schizophrenia, acute mania, and other psychoses, chlorpromazine caused a number of unwanted adverse effects, including neuromuscular rigidity and other extrapyramidal symptoms, sedation, orthostatic hypotension, cognitive slowing, and long-term association with tardive dyskinesia. Although chlorpromazine has been largely supplanted by newer antipsychotic agents, it is still used as a referent for dose equivalency of other antipsychotics. It has also been used in lower doses to treat nausea, vomiting, and intractable hiccups. U.S. trade name: Thorazine.