Consult Your Pharmacist - BP Effects of Nasal Decongestants

US Pharmacist. 2000;25(2) 

In This Article

Safety of Oral Decongestants

Generally, the doses of oral nasal decongestants required to produce a noticeable opening of the nasal passages are higher than those of topical products.[1] This is part of the reason that the incidence of blood pressure abnormalities may be higher than with topicals. In addition, oral nasal decongestants are systemic, affecting many parts of the body remote from the nasal passages, whereas the topical nature of drops and sprays does not allow for a great deal of systemic absorption.

Evidently, the two oral nasal decongestants primarily used are not equal in their ability to raise blood pressure. Even studies on the same ingredient show conflicting results.

Further, studies on normotensive patients might not be usefully extrapolated to allow a rational prediction of the changes in blood pressure in hypertensive patients. For this reason, each will be considered separately.

Pseudoephedrine: Pseudoephedrine is a popular nasal decongestant, found in products such as Sudafed, Vicks NyQuil Multi-Symptom Cold/Flu Relief Liquid, and Robitussin PE. Two randomized, double-blind, crossover trials illustrate the difficulties of interpreting data on hypertension and pseudoephedrine ingestion. In the first, 20 patients with hypertension were given 60 mg of pseudoephedrine or placebo.[3] Patients were controlled with either a low-salt diet (n = 9), antihypertensive agents (n = 4), or both (n = 7). Single doses of 60 mg pseudoephedrine caused a significant rise in systolic blood pressure (and heart rate) but did not affect diastolic BP. In the second study, 25 patients with controlled hypertension were given 60 mg of pseudoephedrine or placebo over 4 weeks.[4] As in the first, study patients continued their antihypertensive interventions. There was no significant change in either systolic or diastolic pressures. In the face of conflicting reports such as these, the pharmacist is well-advised to recom-mend against use of pseudoephedrine in patients who fit one of the labeled warnings.

Phenylpropanolamine: Like pseudoephedrine, phenylpropanolamine (PPA) is widely distributed, found in Contact 12-Hour Cold Capsules, Dimetapp 12-Hour Extentabs, and Robitussin CF, among others. The labels of these products may suggest patients take as much as 150 mg of PPA daily.

Early concern with the effect of PPA on blood pressure stemmed from the drug's use as a diet aid. In the initial report from the FDA OTC review panel on weight control products, experts reviewed several studies. In one placebo-controlled, double-blind trial, 85 mg of PPA resulted in an increase in mean diastolic supine pressures from 70 mmHg to 94 mmHg, with peaks of 100 mmHg or more in 32% of patients.[5] Adverse reactions, such as dizziness, headache, and palpitations, paralleled the increased blood pressure values.

In another study reported in the same document, six medical students were given 85 mg of PPA. Diastolic pressures rose from a baseline mean supine value of 82 mmHg to mean peak supine values of 100 mmHg, with two patients reaching figures greater than 110 mmHg. Adverse effects included malaise, headache, and tightness in the chest.

The panel report also enumerated cases in which PPA was presumed to have caused such adverse reactions as hypertension-induced cerebral hemorrhage, neck pain, palpitations, and arrhythmias. The FDA summarized available studies, noting that 11% of patients given 50 mg of PPA in a timed-release dosage form developed diastolic hypertension (pressures of 100 mmHg or more); a single dose of 85 mg caused diastolic hypertension that was sometimes severe. The FDA concluded that manufacturers would be required to limit the weight control dose to 25-37.5 mg for immediate-release and 75 mg for sustained-release products.

In 1996, the agency moved against PPA once again, with a proposed rule that would change the required labeling for PPA in weight control and nasal decongestant products.[6] FDA stated that its call for comments had produced insufficient data to fully evaluate the risks of PPA use in regard to blood pressure, stroke and seizure, and the risk factors (e.g., hypertension, age, concomitant drug use, disease conditions) that increased the probability of adverse reactions. FDA further strengthened warnings on products containing PPA (e.g., warning against use with any other sympathomimetics and stressing the daily limit of 75 mg).

In addition to the FDA's publications, others report the dangers of PPA. In one, the authors chronicled 142 case reports of adverse drug effects due to PPA.[7] They discovered 45 cases of hypertensive crisis, some with associated intracranial hemorrhage, hypertensive encephalopathy or seizure, and hemorrhage to other organs. A sizable number of these cases occurred with normal dosing.

In another study, researchers tested the hemodynamic effects of PPA in six healthy subjects.[8] A PPA dose of 75 mg did not produce a clinically relevant rise in blood pressure, unless it was combined with 400 mg of caffeine. However, a 150 mg dose did boost blood pressures into the hypertensive range. Although PPA-caffeine combinations were removed from the weight control market several years ago, this finding underscores the warning not to take PPA with any caffeine-containing product, such as coffee or cola drinks.

In another case report, a 17-year-old female with no history of myocardial injury consumed a diet product containing 75 mg of PPA and eventually experienced hypertension (176/110) and subsequent myocardial injury.[9] The authors pointed out the low therapeutic index of PPA and urged caution in its use.

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