FDA Public Health Advisory

On July 8, 1997 the FDA Public Health Advisory issued a Fen Phen Safety Update Information statement regarding reports of valvular heart disease in patients receiving concomitant fenfluramine and phentermine. The FDA stated that patients and health care professionals should be notified of this information. Following is the letter the FDA sent to health care professionals.

Dear Health Care Professional:

The Food and Drug Administration would like to bring to your attention recent reports of valvular heart disease in women treated for obesity with a combination of fenfluramine and phentermine. Fenfluramine and phentermine were approved more than 20 years ago as INDIVIDUAL agents for short-term use in the medical management of obesity. The use of the products concomitantly has never been approved in the United States, although recently, the combination of the two products has been used "off label" by many American health care practitioners for the management of obesity.

Presently there is no conclusive evidence establishing a causal relationship between these two products and valvular heart disease. However, given the seriousness of the reported valvular disease and its rare occurrence in otherwise healthy obese women in this age range, we believe that patients and health care professionals should be notified of this information. To read the entire FDA report click here.


FDA Announces Withdrawal of Fen Phen

On November 15, 1997 the FDA announced the withdrawal of fenfluramine and dexfenfluramine, the contents making up Fen Phen. This action took place after the FDA reviewed new evidence on the “significant side-effects”. The findings are based on doctors who have evaluated patients taking Fen Phen with an echocardiogram had abnormal results despite no symptoms as of yet in 30% of the patients. The FDA recommended anyone taking Fen Phen should discontinue the use of the drug. The following was the immediate release on September 15, 1997 issued by the FDA of the withdrawal of fenfluramine and dexfenfluramine.



The Food and Drug Administration, acting on new evidence about significant side effects associated with fenfluramine and dexfenfluramine, has asked the manufacturers to voluntarily withdraw both treatments for obesity from the market. Dexfenfluramine is manufactured for Interneuron Pharmaceuticals and marketed under the name of Redux by Wyeth-Ayerst Laboratories, a subsidiary of American Home Products Corp. of Madison, N.J., which also manufactures and markets fenfluramine under the brand name Pondimin. Both companies have agreed to voluntarily withdraw their drugs. The FDA is not requesting the withdrawal of phentermine, the third widely used medication for obesity.

The action is based on new findings from doctors who have evaluated patients taking these two drugs with echocardiograms, a special procedure that can test the functioning of heart valves. These findings indicate that approximately 30 percent of patients who were evaluated had abnormal echocardiograms, even though they had no symptoms. This is a much higher than expected percentage of abnormal test results.

“These findings call for prompt action,” said Michael A. Friedman, M.D., the Lead Deputy Commissioner of the FDA. “The data we have obtained indicate that fenfluramine, and the chemically closely related dexfenfluramine, present an unacceptable risk at this time to patients who take them.”

FDA recommends that patients using either of these products stop taking them. Users of these two products should contact their doctors to discuss their treatment.

These new findings suggest fenfluramine and dexfenfluramine are the likely cause of heart valve problems of the type that prompted FDA’s two earlier warnings concerning “Fen Phen,” a combination of fenfluramine and phentermine. “Fen Phen” has been widely used off-label in recent years for the long-term management of obesity.

In July, researchers at the Mayo Clinic and Mayo Foundation reported 24 cases of rare valvular disease in women who took the “Fen Phen” combination therapy. FDA alerted medical doctors that it had received nine additional reports of the same type, and requested all health care professionals to report any such cases to the agency’s MedWatch program (1-800-FDA-1088/fax 1-800-FDA- 0178) or to the respective pharmaceutical manufacturers.

Subsequently, FDA received 66 additional reports of heart valve disease associated mainly with “Fen Phen.” There were also reports of cases seen in patients taking only fenfluramine or dexfenfluramine. FDA requested that the manufacturers of fenfluramine and dexfenfluramine stress the potential risk to the heart in the drugs’ labeling and patient package inserts. FDA continues to receive reports of cardiac valvular disease in persons who have taken these drugs.


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Fen Phen Websites

PPH Primary Pulmonary Hypertension - primary pulmonary hypertension or PPH lawyer specializing in fen phen lawsuit cases, including Redux and Pondimin lawsuits.

Fen Phen Lawyer Redux Settlement - Legal resource provides information on litigation relating to the Fen-Phen settlement.