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Appetite-Suppressant Drugs and Cardiac Valvular Abnormalities.

The diet drugs fenfluramine and dexfenfluramine were withdrawn from the market last year because of reports of cardiac valvular abnormalities in patients taking them. Now three controlled studies suggest that the concern was warranted.

One study compared echocardiographic findings in 233 patients who took the drugs for an average of 20 months in open-label trials and 233 controls matched for sex, age, and body-mass index. The prevalence of significant valvular regurgitation (i.e., at least mild aortic or moderate mitral insufficiency) was significantly higher among diet drug users than among controls (22.7 percent vs. 1.3 percent).

Another study compared echocardiograms of 718 dexfenfluramine recipients and 354 placebo recipients from a randomized trial. The drug-treated group had a significantly higher prevalence of any degree of aortic regurgitation (17 percent vs. 12 percent) and mitral regurgitation (61 percent vs. 54 percent) than the placebo group. However, there was no statistically significant excess of significant valvular regurgitation, based on the definition in the previous paragraph. The average duration of treatment was only 71 days.

The third study identified 9,765 patients who received diet drugs and 9,281 weight-matched controls from a database in the U.K. During an average follow-up of 4 years, there were 11 newly diagnosed cases of idiopathic valvular disorders among patients using dexfenfluramine or fenfluramine, but no cases among controls. Valvular disorders were more likely among patients using the drugs at least 4 months.

Comment: These reports strengthen the case for a causal relation between valvular abnormalities and fenfluramine or dexfenfluramine. Different research designs and durations of exposure probably account for the varying results.

— AS Brett

Published in Journal Watch General Medicine September 15, 1998

Citation(s):

Khan MA et al. The prevalence of cardiac valvular insufficiency assessed by transthoracic echocardiography in obese patients treated with appetite-suppressant drugs. N Engl J Med 1998 Sep 339 713-718.

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Weissman NJ et al. An assessment of heart-valve abnormalities in obese patients taking dexfenfluramine, sustained-release dexfenfluramine, or placebo. N Engl J Med 1998 Sep 339 725-732.

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Jick H et al. A population-based study of appetite-suppressant drugs and the risk of cardiac-valve regurgitation. N Engl J Med 1998 Sep 339 719-724.

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