Promethazine Home>Pharmacy>Drugs_and_Medications>P>Promethazine     Web Pages Phenergan Full prescribing information from RxList. Promethazine - FamilyDoctor.org Information for consumers in English or Spanish. Promethazine A phenothiazine derivative, possesses antihistaminic, sedative, antimotion-sickness, antiemetic, and anticholinergic effects.