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
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
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."
The study also showed that as more time passed after stopping the drug,
fewer valve problems were seen. "This indicates the possibility of
regression," says Shively.
Elyse Foster, MD, director of echocardiography at the University of
California, San Francisco, reviewed the study for WebMD. She says, "The
logical next step is serial studies in those with valve regurgitation to
determine if there is further regression. The study is also reassuring in that
there was no severe disease in this group. However, follow-up studies will be
important to determine whether there is progression of disease in those
- A new study confirms that the diet drug dexfenfluramine (Redux) sometimes
causes mild damage to the heart valves.
- Patients who had been off of the drug for a longer time period had fewer
detected valve problems, suggesting that improvement had occurred.
- Further research should be done to determine whether heart valves continue
to improve with time in these patients.