Fen-phen was an anti-obesity drug that rose to prominence in the U.S. during the mid-1990s. The drug was trumpeted as a "magic pill" for millions of Americans who were looking to lose weight and reduce their body mass index. However, fen-phen's popularity was short-lived; the drug was recalled by the Food and Drug Administration after it was linked to fatal heart valve defects.
Drug Information
The fen-phen drug combination consisted of fenfluramine or dexfenfluramine, an appetite depressant, and phentermine, an anorectic amphetamine. Phentermine has been available since 1959, while fenfluramine --- or Pondimin --- entered the market in 1973. The more powerful Dexenfenfluramine -- or Redux -- was approved by the FDA in 1996. The drug cocktails were intended for use by obese patients, and were prescribed as part of a weight-loss regimen that included proper dieting and exercise.
Background
Dr. Michael Wientraub created fen-phen in 1979 by combining fenfluramine and phentermine to enhance their effectiveness. The drug was tested during a four-year clinical trial of 121 obese patients, ages 18 to 69, with an average body weight of 200 lbs. Patients were divided into a medication group, which took fen-pen, and a placebo group. Participants in the medication group had an average weight loss of 32 lbs. Winetraub's findings were published in a 1992 edition of "Clinical Pharmacology and Therapeutics." Fen-phen gained national exposure after mainstream media outlets started profiling the drug in the mid-1990s. The FDA estimates that approximately 6 million Americans took some form of the drug during the height of its popularity; the majority of users were women.
Adverse Side Effects
In July of 1997, the Mayo Clinic in Rochester, Minnesota reported treating 24 female fen-phen users who were suffering from a rare heart abnormality. The clinic informed the FDA of a possible link between fen-phen, heart valve damage and primary pulmonary hypertension, a fatal lung condition. The August 28, 1997 edition of the "New England Journal of Medicine" chronicled the Mayo Clinic's findings. The edition also included an FDA letter addressing additional reports of fen-phen-related heart valve issues. The FDA required doctors across the U.S. to report any heart valve damage related to the drug; they found that nearly one-third of fen-phen users suffered from heart valve problems. Tests showed that fen-phen caused some patients' heart valves to tighten and leak, a serious problem that often led to severe heart and lung disease. The reactions were atypical so the side effects went undetected during clinical trials.
Aftermath
The FDA recalled fen-phen on September 15, 1997. The National Institutes of Health, FDA and CDC ordered fen-phen users to stop taking the drug and to undergo physical examinations that checked for heart and lung disease. Echocardiograms were also recommended to look for evidence of significant heart disease or heart valve damage. Wyeth Pharmaceuticals, the manufacturer of the drugs Pondimin and Redux, was sued by 42,000 former fen-phen users for injuries, damages and medical expenses. According to "The New York Times," the company settled in 2004 for $4.8 billion. Claims were paid based on the severity of injuries. Future medical checkups for former fen-phen users with no adverse reaction were also covered by the settlement. Phentermine remains on the market since it was not linked to heart valve problems.
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