Phenergan is commonly prescribed for the treatment of nausea, but it can also be used for several other conditions. The drug comes in tablet, rectal suppository, syrup, and injectable form, and is usually taken one to three times daily. Many of the medication's effects are likely due to its antihistamine activity. Potential side effects include drowsiness, confusion, and dry mouth.
What Is Phenergan?
Phenergan® (promethazine hydrochloride) is a prescription medication approved for a variety of widely different uses. It is used most commonly as a nausea medication, although it is frequently used for other purposes as well.
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.
Who Makes This Medication?
Brand-name Phenergan tablets, syrup, and suppositories were made by Wyeth Pharmaceuticals, Inc. but are no longer available. Brand-name Phenergan injection is made by Baxter Healthcare Corporation. Generic versions are made by various manufacturers.
How Does It Work?
Phenergan has several different effects in the body and the brain. Many of the effects are most likely due to its antihistamine activity. This medicine works by blocking histamine receptors. It also belongs to a group of medications known as phenothiazines.
Although phenothiazines are usually used as antipsychotic medications, Phenergan has little dopamine-blocking activity. This makes it a weak antipsychotic medication, and this drug is not used as an antipsychotic.
Phenergan also blocks acetylcholine receptors, which is probably why it helps to alleviate nausea and motion sickness.