DALLAS - The U.S. Food and Drug Administration recently approved Meridia (sibutramine), a new diet drug that has chemical properties similar, but not identical, to Redux and fen/phen (Pondimin).
Redux and fenfluramine, popular diet drugs, were voluntarily withdrawn from the market at the FDA's request after a report in the New England Journal of Medicine (vol. 337, #9, Aug. 28, 1997) linked valvular heart disease with the use of fen/phen, and prior reports linked pulmonary hypertension to the use of Redux (dexfenfluramine) alone.
Primary pulmonary hypertension is an often fatal disorder affecting the blood vessels in the lungs. Valvular heart disease occurs when the heart valve is damaged and either cannot open properly or doesn't close all the way and lets blood leak backward.
"The American Heart Association urges caution when considering the use of Meridia," says Robert H. Eckel, M.D., vice chairperson of the American Heart Association's Nutrition Committee and professor of medicine at the University of Colorado Health Sciences Center. "Although early trials of the drug showed it to be modestly effective, the drug raised concerns because in some individuals it elevates blood pressure." High blood pressure is a serious risk factor for heart attack and stroke. In addition, some individuals experienced increased pulse rates and/or irregular heartbeats.
Prior to drug approval, evidence was provided that the drug was not associated with valvular heart disease, as was the case with fenfluramine and Redux, says Eckel.
"Before definitive data are available, patients and their physicians should carefully weigh the benefits vs. the risks of using this new medication. It is especially important that this drug be considered only for people for whom obesity poses a health risk," he says.
Like Redux and fenfluramine, Meridia in part reduces a person's appetite by interacting with serotonin, a chemical in the brain that makes people feel full.
Obesity, an increasingly prevalent problem in the United States, is also emerging as an independent as well as a contributing risk factor for diseases of the heart, according to a recent science advisory from the American Heart Association. The statement, "Obesity and Heart Disease," was published in the association's journal Circulation (Nov. 4, 1997).
According to the statement, small increases in a person's body mass index (BMI) are associated with an increased risk of both nonfatal and fatal heart attacks, even if the individual has no other risk factors for heart attack. In addition, overweight individuals (BMI above 25) are at greater risk for developing other major risk factors for heart attacks, such as high blood pressure, high cholesterol and diabetes mellitus. Body mass index is defined as weight in kilograms divided by height in meters squared and is considered a better measure of obesity than weight because it more closely approximates the amount of fat on an individual's body.
For people with BMI between 25 and 30, eating a lower-calorie, low-fat diet and becoming more physically active are very helpful at improving overall health. For people with a BMI over 30, treatment with weight loss drugs may be appropriate.
The American Heart Association emphasizes that individuals should use caution and be under a physician's care when taking weight-loss drugs.
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