The combination of phentermine hydrochloride and fenfluramine hydrochloride, known as phen-fen, has been widely used for the treatment of exogenous obesity.1 The therapy has been highly successful. Up to 10 million obese people have been treated, reversing the trend in recent years toward increasing obesity in the US population. In 1996, the Food and Drug Administration approved dexfenfluramine hydrochloride for long-term monotherapy for obesity.
Griffen L, Anchors M. Asymptomatic Mitral and Aortic Valve Disease Is Seen in Half of the Patients Taking ‘Phen-Fen'. Arch Intern Med. 1998;158(1):102. doi: