What Is Phenergan?
Phenergan® (promethazine hydrochloride) is a sedating antihistamine approved for treating nausea and vomiting, motion sickness, allergies, and other conditions. It comes in tablet, rectal suppository, syrup, and injectable form, and is available in the following strengths:
- Promethazine 12.5 mg tablets and rectal suppositories
- Promethazine 25 mg tablets and rectal suppositories
- Promethazine 50 mg tablets and rectal suppositories
- Promethazine 6.25 mg per 5 mL syrup
- Phenergan 25 mg per mL injection vials and ampuls (1 mL)
- Phenergan 50 mg per mL injection vials and ampuls (1 mL).
The medicine works by blocking histamine receptors and acetylcholine 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 it is not used for this purpose.
(Click Phenergan for more information on what Phenergan is used for, to find out what side effects may occur with treatment, and for suggestions on when and how to use it.)