Banned Diet Drugs May Not Be So Bad

From the WebMD Archives

April 4, 2000 (Washington) -- People who took Redux and Pondimin, two diet drugs removed from the market because they were suspected of causing serious heart problems, had only a modest increase in heart valve disorders, and they were usually mild, according to the newest study on these medications.

"Basically, anyone who had taken these drugs certainly for less than three months or so should feel pretty reassured," Julius Gardin, MD, the lead author of the study, tells WebMD. "They should consult their physicians if they have any new symptoms, but if they don't, it would suggest they are in pretty good shape." He says if someone took more than the recommended dose or were taking the drugs for more than three months, his or her physician might consider whether or not a diagnostic heart test is necessary.

Gardin is the chief of cardiology at the University of California, Irvine. The study was published in the April 5 issue of the Journal of the American Medical Association.

Pondimin (fenfluramine) -- which was often given with phentermine, so they are known together as fen-phen -- and Redux (dexfenfluramine) were withdrawn from the market in 1997 after Mayo Clinic physicians reported that up to 30% of people who used them had a leakage in the valve that stops blood from flowing back into the heart, called aortic or mitral valve regurgitation. A handful of studies done after that, however, have failed to find such a high incidence, and this new study, which is the first to look at both medications, is no exception.

The study looked at echocardiograms, or heart ultrasounds, of nearly 500 people who had taken Redux and/or the fen-phen combination. These were compared against those of nearly 500 people who had never taken any of the diet medications. The prevalence of the heart valve disorder in the groups that had taken the medications was not significantly different from the group that had not taken either diet drug, the researchers concluded. Among people who had taken the medications, valve disorders were extremely rare. The groups also showed no difference between the number of heart attacks, irregular rhythms, and other problems that would be considered serious.

Most of the valve disorders were mild and not even detectable with a stethoscope. Gardin says he does not know whether these problems would even cause any symptoms. He tells WebMD that he is now completing a follow-up study examining another year of data on the same study groups, but not because there is a suspicion that problems may occur long after the medications are taken.

"There is nothing in our data that we reported in JAMA to suggest that," he says. "It is just an important question that needs to be answered." Gardin says the drug manufacturers "did the cautious thing" by pulling the medications before studies like his were completed.

"This is a very good study and I am glad they did it," Arthur Frank, MD, tells WebMD. "It is reassuring. It says the frequency of these things is very low and even if they do occur, it does not seem to have a substantial [effect on the heart]." Frank, who reviewed the study for WebMD, is an assistant clinical professor of medicine at George Washington University School of Medicine and Health Sciences.

"I certainly did not believe the early reports," Frank adds. "Why were they seeing what I wasn't seeing? I think the FDA had no choice but to take them off the market because there were some suspicions. ... On the other hand, were they available today, would I use it again? Yep, but I would be selective about who got them and do a lot of monitoring. I had some patients who had such remarkable, dramatic results."

Neil Weissman, MD, who was the lead author of an earlier paper on Redux, says this study "nicely bridges the disparities" among the various studies on these two medications, and should provide a measure of comfort to primary care physicians and patients. Weissman, director of echocardiography at the Cardiovascular Research Institute at Washington Hospital Center and an associate professor of medicine at Georgetown University School of Medicine, says he chalks up the higher incidences of problems initially reported to differences in reading the echocardiograms.

Vital Information:

  • Redux and Pondimin are two diet drugs that were taken off the market because it was suspected that they caused leaks in certain heart valves.
  • A new study shows the drugs caused only a modest increase in valve disorders, which were usually very mild.
  • Patients who took the drugs for less than three months should not be worried about the effects of the drugs on their heart, according to one researcher.