Combination drugs: Nyquil, Nyquil Hot Therapy Powder
Doxylamine is an antihistamine used for short-term treatment of insomnia. Doxylamine is available alone in a nonprescription product for sleep and in combination with nonprescription drugs to treat symptoms of allergy, 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 doxylamine, can cause “anticholinergic” side effects such as dryness of mouth and heart palpitations. Henbane also has anticholinergic activity and side effects. Therefore, use with doxylamine could increase the risk of anticholinergic side effects;1 however, apparently no interactions have yet been reported with doxylamine 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
Doxylamine causes drowsiness.2 Alcohol may intensify this effect and increase the risk of accidental injury.3 To prevent problems, people taking doxylamine or doxylamine-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. Central Nervous System Drugs, Nonprescription Sleep Aids. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Dec 1993, 273e.
3. Threlkeld DS, ed. Central Nervous System Drugs, Nonprescription Sleep Aids. In Facts and Comparisons Drug Information. St. Louis, MO, Facts and Comparisons, Dec 1993, 273e.
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2006-09-07
