In July, FDA sent a letter to the nation's physicians asking them to report any suspicious cases of heart valve disease in people taking diet drugs. As of Aug. 29, the agency had accumulated 101 reports, including the 24 initial ones, of people who have taken fenfluramine or dexfenfluramine, usually in combination with phentermine, and have experienced symptoms of valvular heart disease. Moreover, FDA requested information from echocardiograms of people who had taken these diet drugs but hadn't suffered any symptoms of heart trouble. If such abnormalities get worse, people could be faced with congestive heart failure. The agency recommends that diet drug users stop taking fenfluramine and dexfenfluramine immediately and consult their doctor about whether to get an echocardiogram.
Doctors have no definitive advice, however.
The FDA didn't check the 291 asymptomatic people for heart murmurs. Thus a doctor examining such a person has no way of knowing whether he or she has heart damage. For diet drug users who have already developed symptoms of valvular heart disease, the outlook is also riddled with uncertainty. Doctors don't know whether their valve disease will improve or worsen. Crary notes that he has successfully used medication to improve the heart's pumping power in some fen-phen patients who have serious valve disease.