Detailed examination of fenfluramine-phentermine users with valve abnormalities identified in Fargo, North Dakota

Although several studies have reported on valve abnormalities among users o f fenfluramine or dexfenfluramine, detailed information on these subjects h as not been provided, limiting the ability to understand who may be at risk for valve abnormalities and to generate hypotheses about the etiology and pathogenesis of these abnormalities. This study was a detailed medical reco rd review of 18 previously reported users of Fenfluramine and phentermine, all with valve abnormalities on echocardiogram and 2 with surgical patholog y. Both clinical characteristics and medication use were recorded by traine d abstracters using a standardized data collection form. Two subjects (11%) had other possible etiologies of valve disease: a history of rheumatic fev er and prescribed ergotamine. Three subjects (17%) had a history of migrain e headaches and 4 (22%) had murmurs noted before using fenfluramine. Use of medications that may affect serotonin receptors was common: ergotamine (1 subject, 5%), selective serotonin reuptake inhibitors (6, 33%), sumatriptan (2, 11%), and mirtazapine (1, 5%), Prior medication and nonmedication alle rgies were recorded in 6 (33%) and 3 (17%) subjects, respectively, All subj ects had symptoms possibly due to fenfluramine or phentermine side effects. This study raises the hypotheses that valvular heart disease among fenflur amine users may be less common than previously estimated, that serotonin ex cess may play a role in valve pathology, and that a patient's response to a norexigens and of her medications may serve as a marker for increased risk. Further study is needed to test these hypotheses. (C) 1999 by Excerpta Med ica, Inc.