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Day 4 of Our 31 Day Series of How Medicine Got it Wrong

The Short and Troubling History of Fen Phen

Fen-phen was a weight loss drug combination that included fenfluramine and phentermine. The combination was first introduced in the 1990s and quickly gained popularity as a treatment for obesity. The drug was initially approved by the U.S. Food and Drug Administration (FDA) for short-term use in patients who were obese or overweight and had at least one other risk factor, such as high blood pressure or diabetes.

Dr. Michael Weintraub was a prominent advocate for the use of fen-phen in weight loss. He conducted several studies on the drug combination and presented his findings at medical conferences. His research suggested that the combination was more effective than other weight loss drugs and had fewer side effects.

Fen-phen was widely used around the world, and many patients reported significant weight loss results. However, it soon became apparent that the drug combination had some serious side effects. Some patients developed heart valve damage, a condition called valvular heart disease, which can cause shortness of breath, fatigue, and other symptoms. The risk of developing valvular heart disease was found to be higher in patients who took the drug combination for longer periods or at higher doses.

In 1997, the FDA received reports of heart valve damage in patients taking fen-phen. The agency launched an investigation and eventually recommended that the drug combination be taken off the market. In 1999, the manufacturer of fenfluramine and dexfenfluramine, the two drugs that made up the "fen" part of fen-phen, voluntarily withdrew the drugs from the market. Phentermine, the "phen" part of the combination, remained on the market and is still available as a weight loss medication.

The withdrawal of fen-phen from the market was a major event in the history of pharmaceutical regulation. It highlighted the need for more rigorous testing and monitoring of new drugs, especially those intended for long-term use. The fen-phen case also led to changes in the way that the FDA evaluates the safety and effectiveness of weight loss drugs. Today, weight loss drugs are subject to more extensive testing and monitoring before they are approved for use.

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  1. "The Rise and Fall of Fen-Phen." American Bar Association Journal, 2000, 86(2): 24-27.

  2. "Fen-Phen: A Brief History." Healthline, 2020.

  3. "Fen-Phen." U.S. Food and Drug Administration, 2021.

  4. "Weight-Loss Drugs and Supplements: Do They Work?" Mayo Clinic, 2021.

  5. Image: Fen-Phen and Primary Pulmonary Hypertension by Visually

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