Fen Phen Recall
FDA Withdrawal of Fenfluramine and Dexfenfluramine (Fen Phen)
Announcement
FOR IMMEDIATE RELEASE
September 15, 1997
FDA ANNOUNCES 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.
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Fen-phen
is the common name for the combination of the drugs pondimin
(fenfluramine), redux (dexfenfluramine) and phentermine
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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
FDAs 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 agencys 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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