promazine hydrochloride

Promazine (Sparine) is a phenothiazine neuroleptic used for short-term management of moderate to severe psychomotor agitation and treatment of agitation and restlessness in the elderly. Promazine is an antagonist at types 1, 2, and 4 dopamine receptors, 5-HT receptor types 2A and 2C, muscarinic receptors 1 through 5, alpha(1)-receptors, and histamine H1-receptors. Promazine's antipsychotic effect is due to antagonism at dopamine and serotonin type 2 receptors, with greater activity at serotonin 5-HT2 receptors than at dopamine type-2 receptors. This may explain the lack of extrapyramidal effects. Promazine does not appear to block dopamine within the tuberoinfundibular tract, explaining the lower incidence of hyperprolactinemia than with typical antipsychotic agents or risperidone. Antagonism at muscarinic receptors, H1-receptors, and alpha(1)-receptors also occurs with promazine. Promazine is not approved for human use in the United States. It is available in the US for veterinary use under the names Promazine and Tranquazine. — NCATS