(±)-promethazine

Promethazine, sold under the brand name Phenergan among others, is a first-generation antihistamine, sedative, and antiemetic used to treat allergies, nausea, and vomiting. It may also help with some symptoms associated with the common cold and may also be used for sedating people who are agitated or anxious, an effect that has led to some recreational use (especially with codeine). Promethazine is taken by mouth (oral), as a rectal suppository, or by injection into a muscle (IM).

Common side effects of promethazine include confusion and sleepiness; consumption of alcohol or other sedatives can make these symptoms worse. It is unclear if use of promethazine during pregnancy or breastfeeding is safe. Use of promethazine is not recommended in those less than two years old, due to potentially negative effects on breathing. Use of promethazine by injection into a vein is not recommended, due to potential skin damage. Promethazine is in the phenothiazine family of medications. It is also a strong anticholinergic and at high or toxic doses can act as a deliriant.