Study Confirms Relationship of Diet Drug to Heart Damage
Nov. 22, 1999 (Baltimore) -- A new study supports what some studies have suggested in the past: the diet drug dexfenfluramine (Redux) does cause damage to heart valves. A similar but not identical drug, fenfluramine (Pondimin), was often prescribed with phentermine in the drug combination known as 'fen-phen.' The makers of fenfluramine and dexfenfluramine voluntarily took them off the market once heart problems were suspected.
This is the first study to convincingly show that this association was related to dexfenfluramine alone, says author Bruce Shively, MD, associate professor of cardiology at Oregon Health Sciences University. "Other studies have looked at people treated for a very short period of time with dexfenfluramine, but our study population was unique in that it was truly representative of the millions of patients in the United States who took dexfenfluramine," he said in an interview with WebMD. Another recent study had failed to find any association with heart valve problems.
The study, which was published in the Nov. 23 issue of the journal Circulation, a publication of the American Heart Association, looked at 412 people. One group had taken Redux and another group had not, but other characteristics of the subjects, such as age, sex, and weight, were matched. The group that had taken the drug had done so for an average of about seven months.
Echocardiography, a technique for visualizing the structure of the heart using sound waves, was performed on each person, and the results were reviewed by three cardiologists for the presence and severity of valve problems in the heart.
Valves are four structures in the heart that keep the blood flowing in one direction. When some of the blood flows backward through a valve, it is called regurgitation. Two of these valves, the mitral valve and the aortic valve, showed mild to moderate defects in more people who had taken Redux than in those who had not. "The study strongly suggests that dexfenfluramine is associated with valve disease," Shively says. "However, the frequency is not very high and the severity is usually mild."