Is a Generic Version of Phenergan Available? Phenergan® (promethazine hydrochloride) is a prescription medication approved for treating a variety of different conditions. It is a sedating antihistamine that belongs to a group of medications known as phenothiazines. Brand-name Phenergan tablets, syrup, and suppositories were once made by Wyeth Pharmaceuticals, Inc. but are no longer being manufactured. Brand-name Phenergan injection is made by Baxter Healthcare Corporation. Generic versions are made by various manufacturers. It should be noted that this article applies only to Phenergan products that contain only promethazine as the active ingredient. Some cough syrups (such as Phenergan with Codeine) contain other active ingredients as well.