Fenfluramine and Dexfenfluramine Diet Pills Past

Fenfluramine and dexfenfluramine were marketed under the brand names Redux® and Pondimin®, respectively. Fenfluramine and dexfenfluramine are chemically similar to amphetamine, but they work differently in the body. These drugs exert their effects by increasing the release of serotonin (a neurotransmitter) in the brain, leading to appetite suppression.

Fenfluramine (“fen”) and dexfenfluramine (“dexfen”) were prescription appetite suppressants that had been approved by the FDA for the short-term management of obesity. A landmark study completed in 1992 showed that fenfluramine, when combined with the weight-loss drug phentermine, was very effective for weight loss over the short term. The study results were widely reported, and they led to a surge in popularity of fenfluramine and phentermine. This drug combination, called “fen-phen,” was very effective and proved far more effective than either drug used alone. The combination of dexfenfluramine and phentermine (“dexfen-phen”) had similar effects on weight loss. The FDA never approved the use of these drugs together, however. The drugs, individually or together, were not intended to be used for longer than three months.

Initially, fen-phen was thought to be free of serious side effects. Short-term studies showed the main side effects to be tiredness and diarrhea, and these side effects went away as time passed and the body got used to the drugs. It was known that the “fen-phen” and “dexfen-phen” regimens led
to rare cases of heart, lung, and nerve damage when used for a long time. Unfortunately, many doctors continued to prescribe these combinations for long-term use. This allowed patients who wanted to lose weight—often for cosmetic rather than health reasons—to do so and maintain the
weight loss.

Many people stayed on the “fen-phen” or “dexfen-phen” regimens far longer than the recommended three months to continue or maintain their weight loss. Serious, life-threatening side effects became evident with long-term use of these combinations. Patients developed a lung disease called
primary pulmonary hypertension (PPH), heart valve disease, and other conditions that were irreversible and in some cases life-threatening. PPH is a serious, permanent lung condition that can lead to breathing problems, heart failure, and death. A study investigating the link between fenfluramine and PPH concluded that patients using the diet drugs for longer than three months were 23 times more likely to develop PPH. These horrible effects were attributed mainly to fenfluramine and dexfenfluramine, and eventually the FDA banned these drugs from the market.

Phentermine is still available for weight loss which is the only drug from this class that is perfectly safe. The most startling and damaging news regarding “fen-phen” and “dexfen-phen” came when the Mayo Clinic, in June 1997, reported 24 cases of heart valve damage in “fen-phen” users. Individuals in the study used “fen-phen” for an average of 12 months, well exceeding the recommended three months. Fenfluramine and dexfenfluramine caused leakage in the heart valves. The mitral and aortic
valves, which control blood flow through part of the heart, were most affected. Valve leakage prevents the heart from pumping effectively. In five cases, patients required open heart valve surgery.
After many health problems and deaths, the FDA removed Pondimin and Redux from market. Since then, there have been 200 reported cases of primary pulmonary hypertension relating to “fen-phen” and “dexfen-phen.”

Of those cases, 40 have resulted in death. The FDA has received more than 100 reports of heart valve damage directly related to “fen-phen” or fenfluramine therapy; there are no reports from individuals taking phentermine alone for weight loss.