Safe, effective long-term weight-loss pill remains elusive

Last reviewed: February 2011

The Food and Drug Administration turned down two applications for new anti-obesity drugs in recent months, in part because of safety concerns.

But on Dec. 7, 2010, an FDA advisory committee recommended approval of a new weight-loss drug. Called Contrave, it is a combination of two older medications: naltrexone, used to treat alcohol and drug addiction, and bupropion, an antidepressant. In a 56-week clinical trial, obese patients on Contrave lost an average of 5 to 6 percent of their starting weight, compared with a little more than 1 percent for patients on placebo. A significant number reported side effects from Contrave, including nausea, constipation, and dizziness. A final FDA decision on Contrave was expected in January 2011.

With the October 2010 removal of Meridia (sibutramine) from the market because of the risk of major cardiovascular side effects, there's only one prescription weight-loss medication currently approved for long-term use in the U.S. It's Xenical (orlistat), which blocks your body from absorbing 30 percent of the fat you ingest. Also available in a lower over-the-counter dose under the Alli brand name, Xenical has never achieved the widespread popularity once expected.

That might be because of intestinal side effects, caused by the undigested fat, that could result in oily spotting. And in clinical trials of orlistat, severely overweight patients on a reduced-calorie diet lost only about 7 pounds more after a year of treatment than subjects who took placebos.

 On Jan. 31, 2011, the FDA declined to approve Contrave for sale. According to a statement from the drug's manufacturer, Orexigen Therapeutics, the agency was concerned about the cardiovascular safety of the drug.