The FDA has issued a new warning on the weight-loss drug sibutramine (marketed as Meridia or Reductil), cautioning patients with a history of heart disease or an elevated stroke risk that use of the drug could further boost the likelihood of cardiovascular events. The agency's advisory comes in the same week that the European Union's European Medicines Agency recommended a ban on the diet drug, prompting its maker to withdraw sibutramine from the European market.
Sibutramine, a prescription weight-loss medication on the U.S. market since 1998, is a combination drug that increases the availability in the brain of serotonin and norepinephrine--a class of drugs also used as antidepressants and known as SNRIs. It is thought to aid in weight loss by helping to curb the appetite and enhance a patient's sense of fullness.
The FDA's latest advisory notifies physicians that the agency has found an increased risk of heart attack and stroke in people taking sibutramine who have a history of heart attack, angina, heart failure, stroke or transcient ischemic attacks. Other groups warned against sibutramine use are those with a history of heart arrhythmia or peripheral artery disease, or uncontrolled high blood pressure--all conditions that put patients at greater risk of stroke.
The warning will likely affect a substantial segment of patients taking sibutramine, since obesity is closely associated with many of those conditions. It's based on the results of a study conducted by Abbott Labs, maker of sibutramine, that found that 11.4% of subjects with the underlying conditions and who took sibutramine had a cardiovascular event. By comparison, 10% of subjects taking a placebo did so. The FDA's been contemplating the new data since November.
The label accompanying sibutramine prescriptions will now list those as conditions that should prompt a physician to consider a different therapy for a patient's weight loss.
Unfortunately, there is little else--particularly pharmacological--that has been shown safe and effective for long-term use by the overweight and obese. Currently, the FDA has approved for long-term use only sibutramine and the fat-blocker orlistat--marketed as Xenical and more recently in over the counter form as Alli. For short-term use, it has approved phentermine, diethylpropion and phendimetrazine. A new crop of weight-loss drugs is moving toward FDA consideration in the coming months and years.
In a recent L.A. Times story, a researcher called the pharmacological prescriptions for weight loss "lousy," and said that fact has focused increasing attention on the use of gastic bypass and other forms of bariatric surgery as the most effective means of weight loss now available to the obese. Meanwhile, despite a dearth of evidence that they work, there's plenty of money being made by the makers of weight loss supplements, as a recent L.A. Times story showed.
-- Melissa Healy