Public Release: 

Benefits Of New Diet Drug Don't Outweigh Risks

Cornell University

ITHACA, N.Y. -- Don't bother with the hot new diet pill Redux -- the benefits don't outweigh the risks, according to a Cornell University nutritionist who has examined the 40 studies on long-term use of the diet pill. "People do lose weight more easily with Redux (d-fenfluramine) than with a placebo, but the advantage of taking the medication over a placebo after a year is less than 5-and-a-half pounds," said David Levitsky, professor of nutritional sciences and of psychology in the Division of Nutritional Sciences and Department of Psychology at Cornell and a nationally known expert on the control of obesity.

That amount of weight lost after one year of taking the drug daily rather than a placebo is equivalent to a 62-calorie difference a day, roughly the amount of calories in a medium-sized cookie or apple, or the amount burned by walking for a half-hour and making other small changes in daily motor activity. After one year, there is no indication that any further weight loss can be achieved by the medication alone, Levitsky said.

Until recently patients were prescribed appetite suppressing drugs such as Redux for no longer than 12 weeks to help them stick to their diets and lose weight. In the past several years, however, researchers and clinicians have observed that body weight returns to pretreatment levels when the medication is discontinued. Consequently, they have largely agreed that for weight reduction drugs to be effective, people must take them chronically, perhaps for a lifetime.

To determine just how much weight people could expect to lose if they took Redux or a similar drug for a long time, Levitsky analyzed the studies from all the articles published in scientific, peer-reviewed journals in which patients remained on fenfluramine for more than three months. His analysis is published in the January/February issue of Healthy Weight Journal, a publication intended for professional dietitians and clinical weight loss personnel.

Levitsky concluded that Redux not only produces a relative small weight loss but also may carry health risks.

"Although conclusive evidence of possible health risks from chronically taking fenfluramine or any other weight loss medication is not in, there is some evidence of brain damage in animals and pulmonary hypertension in animals and humans," he said.

In fact, in one case-controlled 1996 study of 95 patients, patients suffering from pulmonary hypertension were 23 times more likely to have taken d-fenfluramine than their matched controls and that the longer they had been taking the medication, the greater their risk of developing this serious condition. In an article published in the same issue of the journal, it is reported that Redux also is associated with sleep problems, drowsiness, headaches, dizziness, vertigo, nervousness, anxiety, depression and abnormal dreams and that discontinuing the drug is related to depression, delusion, hypertension and nausea.

Nevertheless, some researchers argue that even though d-fenfluramine has an increased health risk associated with it, the risks associated with obesity are far greater. They argue that these risks can be reduced by weight loss, perhaps achieved by taking appetite suppressing drugs. Levitsky disagrees: "There is no evidence that losing weight with the help of appetite suppressants is as effective at reducing mortality as losing weight through more conventional techniques such as reducing dietary fat and increasing exercise."

He emphasized that the burden of proof rests with the advocates of the weight-reducing medications to show that the benefits of the weight loss from the medications is equivalent to that of improving diets in reducing mortality.

"We know that d-fenfluramine is not a completely safe drug, and we know that simple lifestyle changes such as modest exercise or changing the kinds of food we eat from having an average of 34 percent of total calories from fat to an average of 25 percent of calories from fat can easily produce a deficit equal to or greater than the amount of weight lost by chronically taking diet pills. We also know these changes in lifestyle will not only lower body weight but also reduce the risk of cardiovascular disease and cancer as well.

"Yet, Americans have a love affair with the idea of a 'magic bullet,' and this is inflamed by the advertising and pharmaceutical industries," Levitsky said. "However, enough evidence is in for me to conclude: the perils of weight loss pills far outweigh the modest weight loss they achieve, even when taken for years."


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