Combination drugs: Phenergan VC, Phenergan VC with Codeine, Phenergan with Codeine
Promethazine is an antihistamine used to relieve allergic rhinitis (seasonal allergy) symptoms including sneezing, runny nose, itching, and watery eyes and itching and swelling associated with uncomplicated allergic skin reactions. It is also used as a sleep aid for surgical procedures and to prevent/treat motion sickness, nausea, and vomiting. Promethazine is available as a nonprescription product alone and in a combination product to treat symptoms of allergy, colds, and upper respiratory infections. It is also available in prescription products with codeine, to treat coughs associated with colds and upper respiratory infections.
Summary of Interactions with Vitamins, Herbs, and Foods
In some cases, an herb or supplement may appear in more than one category, which may seem contradictory. For clarification, read the full article for details about the summarized interactions.
 Avoid: Adverse interaction—Avoid these supplements when taking this medication because taking them together may cause undesirable or dangerous results. | Henbane* |
| Depletion or interference | None known |
| Side effect reduction/prevention | None known |
| Supportive interaction | None known |
| Reduced drug absorption/bioavailability | None known |
An asterisk (*) next to an item in the summary indicates that the interaction is supported only by weak, fragmentary, and/or contradictory scientific evidence.
Interactions with Herbs
Henbane (Hyoscyamus niger)
Antihistamines, including promethazine, can cause “anticholinergic” side effects such as dryness of mouth and heart palpitations. Henbane also has anticholinergic activity and side effects. Therefore, use with promethazine could increase the risk of anticholinergic side effects,1 though apparently no interactions have yet been reported with promethazine and henbane. Henbane should not be taken except by prescription from a physician trained in its use, as it is extremely toxic.
Interactions with Foods and Other Compounds
Alcohol
Promethazine causes drowsiness.2 Alcohol may intensify this effect and increase the risk of accidental injury.3 To prevent problems, people taking promethazine or promethazine-containing products should avoid alcohol.
References
1. Blumenthal M, ed. The Complete German Commission E Monographs. Austin, TX: American Botanical Council, 1998, 146.
2. Threlkeld DS, ed. Respiratory Drugs, Antihistamines. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, May 1998, 192b–2c.
3. Threlkeld DS, ed. Respiratory Drugs, Antihistamines. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, May 1998, 192b–2c.
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2006-09-07
