All Rights Reserved. Duplication for commercial use must be authorized by ASHP. Copyright, 2022. The American Society of Health-System Pharmacists®, 4500 East-West Highway, Suite 900, viagra tablet Bethesda, Maryland. AHFS® Patient Medication Information™. Promethazine is a first-generation antihistamine used for the treatment of allergic conditions, nausea and vomiting, and motion sickness.