Promethazine is a generic name for a class of antihistamine drugs used to prevent motion sickness, nausea, or vomiting; and for sedation, and the treatment of itching related to allergies. It is in the latter that we're interested in here, treating allergy symptoms and reactions with Promethazine, such as: nasal congestion, itching nose, clear runny nose, sneezing, itchy or watery eyes, hives, and itchy skin rashes. Brand names of promethazine include Phenadoz, Phenergan, and Promethegan. The FDA has approved Promethazine in 1951.