Promethazine

Promethazine is a first-generation H1 receptor antagonist antihistamine and antiemetic medication. It is a prescription drug in the United States, but is available over the counter in the United Kingdom, Switzerland, and many other countries (brand names Phenergan®, Promethegan®, Romergan, Fargan®).

Promethazine also has strong anticholinergic and sedative/hypnotic effects. Previously it was used as an antipsychotic, although it is generally not administered for this purpose now; promethazine has only approximately 1/10 of the antipsychotic strength of chlorpromazine.