Phenergan suppositories are approved for various uses, but are most commonly used for treating nausea and vomiting. The product is inserted rectally and works by blocking histamine receptors and acetylcholine receptors. This medication is available by prescription only and come in two different strengths. Some of the most commonly reported side effects include confusion, dry mouth, and drowsiness.
Phenergan® suppositories are a rectal form of promethazine hydrochloride. They are available by prescription only and are approved for various uses. The suppositories are probably most commonly used to treat nausea and vomiting. They are especially useful for this purpose since nausea and vomiting can limit a person's ability to take medications by mouth.
Brand-name Phenergan suppositories were once made by Wyeth Pharmaceuticals, Inc. but are no longer manufactured. Generic versions are made by several manufacturers.
The active ingredient in Phenergan suppositories (promethazine) is absorbed into the bloodstream and has several different effects in the body and the brain. Many of these effects are most likely due to the drug's antihistamine activity since it works by blocking histamine receptors. Promethazine also blocks acetylcholine receptors, which is probably why it helps to alleviate nausea and motion sickness.
Promethazine belongs to a group of medications known as phenothiazines. Although phenothiazines are usually used as antipsychotic medications, promethazine has little dopamine-blocking activity. This makes it a weak antipsychotic medication, and it is not used for this purpose.