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 over-the-counter weight loss products.
Phenylpropanolamine 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 phenylpropanolamine.
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.
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 (To view, roll mouse over the "References" heading; to hide, click on the heading)
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.
The information presented in Aisle7 is for informational purposes only.
It is based on scientific studies (human, animal, or in vitro), clinical experience,
or traditional usage as cited in each article. The results reported may not necessarily occur
in all individuals. For many of the conditions discussed, treatment with prescription or over
the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist
for any health problem and before using any supplements or before making any changes in
prescribed medications.
