Fen-phen refers to the use in combination of fenfluramine and phentermine. Phentermine has also been used in combination with dexfenfluramine ("dexfen-phen"). Fenfluramine ("fen") and phentermine ("phen") are prescription medications that have been approved by the FDA for many years as appetite suppressants for the short-term (a few weeks) management of obesity. Phentermine was approved in 1959 and fenfluramine in 1973. Dexfenfluramine (Redux) was approved in 1996 for use as an appetite suppressant in the management of obesity. Recently, some physicians have prescribed fenfluramine or dexfenfluramine in combination with phentermine, often for extended periods of time, for use in weight loss programs. Use of drugs in ways other than described in the FDA-approved label is called "off-label use." In the case of fen-phen and dexfen-phen, no studies were presented to the FDA to demonstrate either the effectiveness or safety of the drugs taken in combination.

On July 8, 1997, the Mayo Clinic reported 24 patients developed heart valve disease after taking fen-phen. In five patients who underwent valve replacement surgery, the diseased valves were found to have distinctive features similar to those seen in carcinoid syndrome. The cluster of unusual cases of valve disease in fen-phen users suggested that there might be an association between fen-phen use and valve disease.

On July 8, FDA issued a Public Health Advisory that described the Mayo findings. The Mayo findings were reported in the August 28 issue of the New England Journal of Medicine, along with an FDA letter to the editor describing additional cases. FDA has received over 100 reports (including the original 24 Mayo cases) of heart valve disease associated mainly with fen-phen. There were also reports of cases of heart valve disease in patients taking only fenfluramine or dexfenfluramine. No cases meeting FDA's definition of a case were reported in patients taking phentermine alone.

Within the past several weeks, additional information received by the FDA has raised more concern. Most of the cases previously brought to the FDA's attention were in patients who had symptoms of heart disease. Recently, FDA has received reports from five physicians who had performed heart studies (echocardiograms) on patients who had received fen-phen or dexfen-phen and did not have symptoms of heart disease. Of 291 asymptomatic patients screened, about 30 percent had abnormal valve findings, primarily aortic regurgitation. Based on these data, the manufacturers have agreed to withdraw the products from the market and FDA has recommended that patients stop taking the drugs.

Click Here if you think you have PPH as a result of taking fen-phen.