A common ingredient in over-the-counter decongestants — pseudoephedrine — may increase blood pressure and the risk of life-threatening or disabling strokes in susceptible patients, researchers at Vanderbilt University Medical Center have reported.
"At the usual doses, (pseudoephedrine) is probably safe for most people," says Italo Biaggioni, M.D., professor of Medicine and Pharmacology and director of the Vanderbilt Clinical Trials Center. "The concern for the general population is there might be susceptible individuals who might respond to normal doses of these medications with dangerous increasing blood pressure and even strokes."
People at potential risk may include those with high blood pressure, a history of previous strokes, and diabetes ñ a disease that can damage the nerves that help maintain normal blood pressure.
Biaggioni recommends that people check their blood pressure an hour after taking a decongestant containing pseudoephedrine. If blood pressure rises, "you know you shouldn’t continue to take it," he says. "Having a cold makes your life miserable, but nobody dies of nasal stuffiness."
In a study placed on the website of the medical journal Circulation this week<April 5>, Biaggioni and his colleagues found that blood pressure increased significantly in 13 patients with autonomic failure when they swallowed a small dose of pseudoephedrine and 16 ounces of water. Autonomic failure is the inability to control blood pressure. It is easier to study the impact of medications on blood pressure in patients who lack the normal neurological mechanisms for blood pressure regulation.
Systolic blood pressure (a measure of the maximum pressure exerted when the heart contracts) increased by an average of 52 millimeters of mercury in these patients one hour after they were given 30 milligrams of pseudoephedrine with the water. "Extended release" over-the-counter decongestants may contain 120 milligrams of pseudoephedrine, to be taken twice daily.
The patients in this study are disabled because their blood pressure drops precipitously when they stand, causing them to faint. This condition is known as orthostatic hypotension. Used cautiously, the combination of pseudoephedrine and water can prevent blood pressure from plunging when the patients stand, and therefore can be given as a treatment their condition. However, the researchers would not give the combination without first determining the patients’ susceptibility to pseudoephedrine.
The problem occurs when susceptible people unknowingly take these over-the-counter medications without medical supervision, Biaggioni says.
Four years ago, another decongestant, phenylpropanolamine, was pulled from the market because of an association with hemorrhagic (bleeding) strokes. The U.S. Food and Drug Administration recently announced plans to ban ephedra-containing dietary supplements because they also can raise blood pressure and increase the risk of stroke. "The chemical structure of ephedra and pseudoephedrine is exactly the same," Biaggioni notes.
It is not known to what extent pseudoephedrine-containing products increase the risk of stroke. But some studies have documented strokes in patients after they took recommended doses of the pseudoephedrine. "In the long-term, I think it will be better if we find a safer alternative" for decongestants, Biaggioni says.
The lead author of the Vanderbilt study was Jens Jordan, M.D., a former Vanderbilt post-doctoral fellow in clinical pharmacology who is now a professor at Humboldt University in Berlin, Germany. Others included John R. Shannon, M.D., AndrÈ Diedrich, M.D., Bonnie Black, R.N., and David Robertson, M.D., of the Vanderbilt Departments of Medicine and Pharmacology.
The research was supported by the National Institutes of Health and conducted with the assistance of General Clinical Research Center at Vanderbilt.
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John Howswer
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john.howser@vanderbilt.edu