The Food and Drug Administration urged millions of dieters Monday to immediately stop taking Redux, also known as dexfenfluramine, and Pondimin, or fenfluramine, which is half of the popular fen-phen diet combination.
The drugs' U.S. distributor, Wyeth-Ayerst Laboratories, stopped sales of the medicines Monday and said dieters could return unused portions for a refund. The U.S. decision prompted the French manufacturer, Servier, which handles sales abroad, to pull both drugs off the market worldwide.
Obesity experts said the decision was right, because the diet pills have been linked to serious damage of patients' heart valves, damage that over time could dangerously weaken the heart.
But Monday's announcement left patients not only wondering if their hearts were hurt, but what alternatives to try now that only one prescription diet drug remains for sale in this country.
"We are anticipating lots of very desperate patients that need help," said Dr. John Foreyt, an obesity expert at Baylor College of Medicine.
"Discretion is the better part of common sense right now," said Dr. Richard Atkinson, president of the American Obesity Association. Still, "all of the problems of obesity will come back" when patients stop the pills and many regain their weight.
The FDA said it was OK for dieters to continue taking the other half of fen-phen, a drug called phentermine that appears safe as long as it is taken alone.
Some doctors say phentermine is very effective, noting that the fen-phen combination became popular not because it was markedly better but because phentermine alone can make people jittery while fenfluramine calms them down.
Other doctors disagree, saying phentermine alone isn't terribly effective.
But alternatives are scarce. The FDA told Knoll Pharmaceuticals last fall that its new appetite suppressant, called sibutramine, was on track to be approved, but the drug still is in limbo.
Knoll said Monday that it expects approval by year's end, but diet doctors questioned the delay and Knoll would not say whether the FDA is rechecking for side effects in wake of its competitors' surprise heart problems.
An experimental drug that was generating more excitement, because it can help dieters absorb less fat from food, got sidetracked last month. Hoffman-La Roche withdrew its FDA application for Xenical after the agency questioned a test in which a few more women who tested the drug were diagnosed with breast cancer than were women given a dummy pill. Roche is reanalyzing the data to ensure the finding was an anomaly, and plans to again seek FDA approval in a few months.
So-called herbal fen-phen isn't a good choice, either, Atkinson said. The dietary supplements claim to help people lose weight using the herbal version of the chemical ephedrine, but a pending FDA proposal would ban such products as unsafe.
"Just because it's natural doesn't mean it's good for you," Atkinson warned.
"The alternatives are to eat sensibly and exercise regularly," Foreyt said.
Says FDA Acting Commissioner Dr. Michael Friedman: "These medications have never been by themselves ways of simply and permanently having people lose weight. ... They have limited benefit."
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