Phenylpropanolamine

Also indexed as: Acutrim®, Dex-A-Diet®, Dexatrim®, Phenldrine®, Phenoxine®, PPA, Propagest®, Rhindecon®, Unitrol®

Combination drugs: Ami-Tex® LA, Appedrine®, Contac® 12 Hour, DayQuil® Allergy Relief, Dex-A-Diet® Plus Vitamin C, Diadex® Grapefruit Diet Plan, Dimetapp®, Entex® LA, Robitussin® CF, Tavist®-D, Triaminic®-12

Phenylpropanolamine is a drug used to relieve nasal congestion due to colds, hay fever, upper respiratory allergies, and sinusitis. It is available in nonprescription products alone and in combination with other nonprescription drugs, to treat symptoms of allergy, colds, and upper respiratory infections. Phenylpropanolamine is also used as an adjunct to calorie restriction in short-term weight loss. It is available in nonprescription products alone and in combination with other ingredients for weight loss.

The Food and Drug Administration (FDA) has taken steps to remove phenylpropanolamine from all drug products and has issued a public health advisory concerning phenylpropanolamine hydrochloride. This drug is an ingredient used in many over-the-counter (OTC) and prescription cough and cold medications as a decongestant and in OTC weight loss products. PPA has been found to increase the risk of hemorrhagic stroke (bleeding into the brain or into tissue surrounding the brain) in women. Men may also be at risk. Although the risk of hemorrhagic stroke is very low, FDA recommends that consumers not use any products that contain PPA.

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 Avoid: Adverse interaction—Avoid these supplements when taking this medication because taking them together may cause undesirable or dangerous results.

Caffeine

Ephedra*
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

Ephedra
Ephedra is the plant from which the drug ephedrine was originally isolated. Phenylpropanolamine and ephedrine have similar effects and side effects.1 Until 2004, ephedra, also called ma huang, was used in many herbal products including supplements promoted for weight loss.

While interactions between phenylpropanolamine and ephedra have not been reported, it seems likely that such interactions could occur. To prevent potential problems, people taking phenylpropanolamine-containing products should avoid using ephedra/ephedrine-containing products.

Interactions with Foods and Other Compounds

Caffeine
Phenylpropanolamine can increase blood pressure,2 a danger especially in people with high blood pressure.3 In a double-blind study of six healthy people, administration of caffeine and phenylpropanolamine produced an additive increase in blood pressure.4 Additionally, in a study of 16 healthy people, phenylpropanolamine plus caffeine resulted in higher serum caffeine levels than when caffeine was given alone.5

Caffeine is found in coffee, tea, soft drinks, chocolate, guaraná (Paullinia cupana), nonprescription drugs, and supplement products containing caffeine or guaraná. People taking phenylpropanolamine-containing products can minimize the interaction with caffeine by limiting or avoiding caffeine.

References

1. Threlkeld DS, ed. Respiratory Drugs, Sympathomimetics. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, May 1994, 173a–3h.

2. Hoffman BB, Lefkowitz RL. Catecholamines, sympathomimetic drugs, and adrenergic receptor antagonists. In Goodman and Gilman’s The Pharmcological Basis of Therapeutics, 9th ed. New York: McGraw-Hill, 1996, 223.

3. Threlkeld DS, ed. Respiratory Drugs, Sympathomimetics. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Apr 1993, 173a–3h.

4. Brown NJ, Ryder D, Branch RA. A pharmacodynamic interaction between caffeine and phenylpropanolamine. Clin Pharmacol Ther 1991;50:363–71.

5. Lake CR, Rosenberg DB, Gallant S, et al. Phenylpropanolamine increases plasma caffeine levels. Clin Pharmacol Ther 1990;47:675–85.