Promethazine

a phenothiazine derivative having marked antihistaminic activity as well as sedative and antiemetic actions; used to provide bedtime, surgical, and obstetrical sedation, to treat allergic conditions including rhinitis, conjunctivitis, and itching, to manage nausea, vomiting, and vertigo associated with surgery, pregnancy, or motion sickness, and as an ingredient in cough and cold preparations; administered orally, rectally, intramuscularly, and intravenously as the hydrochloride salt.