Browse eMedTV's wide range of articles related to drugs including topics such as gemfibrozil, levoxyl, and ketorolac. Use the search box at the top-right corner of the page to find information about other health topics. The recommended dosage of Phenergan for treating motion sickness in adults is 25 mg (in tablet, rectal suppository, or syrup form) twice daily. Promethazine is a first-generation antihistamine. It is used to treat allergies, trouble sleeping, and nausea. It may help with some symptoms associated with the common cold. It may also be used for sedating people who are agitated or anxious. Promethazine is used to relieve the symptoms of allergic reactions such as allergic rhinitis (runny nose and watery eyes caused by allergy to pollen, mold or dust), allergic conjunctivitis (red, watery eyes caused by allergies), allergic skin reactions, and allergic reactions to blood or plasma products. Phenergan Tablets and Phenergan Rectal Suppositories are contraindicated for children under 2 years of age (see WARNINGS–Black Box Warning and Use in Pediatric Patients). Phenergan (promethazine HCI) Tablets and Suppositories only DESCRIPTION Each tablet of Phenergan contains 12.5 mg, 25 mg, or 50 mg promethazine HCl. phenergan should not be used in pediatric patients less than 2 years of age because of the potential for fatal respiratory depression. postmarketing cases of respiratory depression, including fatalities, have been reported with use of phenergan in pediatric patients less than 2 years of age. PHENERGAN™ (promethazine hydrochloride) Suppositories, USP. DESCRIPTION. Each rectal suppository contains 12.5 mg or 25 mg promethazine HCl with ascorbyl palmitate, colloidal silicon dioxide, white wax, hard fat, and glyceryl monostearate. Pennsylvania Department of Human Services Preferred Drug List (PDL) Effective January 20, 2016 AR = Age Restriction, Clinical Prior Authorization Required PA = Clinical Prior Authorization Required QL = Quantity Limit Applies printable. Compounding Formulas from the Recent Journal Literature. Compounding formulas are cited from recent (1997+) issues of four pharmacy journals.