Valvular Heart Disease Associated with Fenfluramine–Phentermine

Abstract

Nineteen of the 24 patients described by Connolly et al. (Aug. 28 issue)¹ in the primary report linking fenfluramine and phentermine with cardiac valvular abnormalities were identified in Fargo, North Dakota, a city with only 74,111 residents in 1990.² Twelve of the Fargo cases, and perhaps the association itself, were initially identified by an astute echocardiographic sonographer. This relation had not been discovered previously despite the fact that fenfluramine has been approved since 1973 and that 18 million prescriptions for these drugs were filled in 1996 alone.¹ Diagnosis of a cardiac abnormality in 18 of the 24 patients was based on echocardiographic findings of valvular insufficiency and “unusual valvular morphology.” ¹ The key unanswered question is whether these echocardiographic abnormalities have clinical import for the majority of patients using these drugs or whether they are simply a visual finding. The drugs are so widely used and these reports have prompted such widespread concern that all efforts should be taken to be certain that the association with important heart disease is real. On the other hand, if the incidence rate in Fargo is confirmed and if the echocardiographic abnormalities frequently lead to clinically significant disease, these drugs will be responsible for a major epidemic of valvular heart disease that could have been far worse if not detected by the echocardiographer.