Fen-Phen is a combination drug made up of fenfluramine and phentermine, and was used primarily in weight loss pills. In 1997, Fen-Phen was recalled after it was linked to heart-valve disease.
American Home Products, now known as Wyeth, originally marketed fenfluramine and later a similar drug named dexfenfluramine. While phentermine was not shown to cause harmful effects, fenfluramine usage was linked to heart valve disease and other dangerous side effects.
Fen-Phen Linked to Heart Valve Disease
Wyeth also manufactured other drugs, marketed as Redux and Pondimin, which used the fenfluramine half of the fen-phen combination formula. Medical studies have linked both Pondimin and Redux to heart valve disease, as well.
In a separate Mayo Clinic study, one-third of patients taking Fen-Phen showed evidence of heart valve disease.
In addition to heart valve disease, fenfluramine and dexfenfluramine use has been found to increase the risk of developing Primary Pulmonary Hypertension (PPH), a rare disease that causes blood valves in the lungs to narrow.