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A Closer Look: Weight-loss drugs

Several have recently come before the FDA. Do they work? Are they safe?

December 13, 2010|By Jill U. Adams, Special to the Los Angeles Times

For many people who carry excess pounds, lifestyle changes don't do enough or are too hard to maintain day in and day out.

The pharmaceutical industry has been trying to create weight-loss medicines — it is a huge market, after all — but the failures have outnumbered the successes. Dr. Kevin Niswender, an obesity expert at Vanderbilt University in Nashville, says every talk he gives begins with a slide that says: "Pharmacotherapy for obesity has a troubled past — and future."

Part of the problem is that if there's a drug they can take, people wrongly think they can stop the harder work of diet and exercise. Doctors who specialize in treating overweight and obese patients say that, at best, medications should be used as an adjunct to lifestyle change. "If you overeat, you're going to overcome the drug," says Dr. David Heber, who directs the UCLA Risk Factor Obesity Program.

The other problem for candidate drugs has been their safety profile, with cardiovascular side effects a particular issue, Niswender says. The medical rationale for losing weight is to prevent the development of obesity-related health conditions, such as heart disease and stroke. So a weight-loss drug that increases blood pressure is defeating part of its own purpose.

Here's a closer look at the most recent weight-loss drugs to come before the Food and Drug Administration.

Contrave

What it is: It's a combination of two drugs already used for other health conditions: bupropion (Wellbutrin, Zyban), an antidepressant that's also used to help people quit smoking; and naltrexone (Revia), an antidote to heroin overdose that is also used to help curb alcoholic cravings.

Weight-loss results: A study published in the Lancet in August followed 1,453 overweight or obese patients — half of them for more than a year — and found that those on Contrave lost 5% (lower dose) and 6.1% (higher dose) of their initial body weight compared with a 1.3% loss in the placebo group. Another trial published online in June in the journal Obesity that also included training in diet and exercise found an average 9.3% weight loss with the higher dose compared with 5.1% with a placebo.

Safety profile: Some patients experienced a modest rise (1.5 mm Hg) in blood pressure. Headache, constipation and nausea were also reported.

FDA action: Approval recommended by an expert advisory panel on Dec. 7.

Qnexa

What it is: It's a combination drug made up of phentermine, a well-known appetite suppressant, and topiramate, which is used to treat epilepsy and migraine headaches.

Weight-loss results: In 1,542 overweight and obese patients, those who took Qnexa for more than a year lost an average of 10.5% (lower dose) and 13.2% (higher dose) of their body weight compared with 2.4% of weight loss in the placebo group, according to company literature.

Safety profile: The main concerns of the advisory panel were the drug's potential to cause birth defects in women of child-bearing age and an increase in heart rate in some patients. Other side effects were dry mouth, tingling and constipation.

FDA action: An advisory panel recommended against approval in October. The agency detailed what the company ( Vivus) would need to address in a subsequent application. These included managing potential serious side effects and submitting data from patients who had taken the drug for two years.

Lorcaserin (Lorqess)

What it is: The drug acts on one of many serotonin receptors in the brain to suppress appetite.

Weight-loss results: A study published in the New England Journal of Medicine in July followed 1,599 overweight or obese patients for a year and found that those on lorcaserin lost an average of 5.8% of their initial body weight compared with 2.2% in the placebo group. A second trial found an average 5.9% weight loss in the drug group compared with 2.8% in the placebo group in about 2,000 overweight or obese patients followed for a year.

Safety profile: The FDA advisory panel cited concerns about tumor growth in animal studies. Other side effects were headache, dizziness and nausea.

FDA action: The panel recommended against approval in October. The agency detailed what the company ( Arena Pharmaceuticals) would need to address in a subsequent application, such as more information about potential serious side effects.

Sibutramine (Meridia)

What it is: The drug acts to increase levels of two neurotransmitters in the brain, serotonin and norepinephrine,to reduce appetite.

Weight-loss results: Studies in the 1990s found that two-thirds of patients taking Meridia lost 5% or more of their body weight over a one-year period. However, subsequent studies after the drug was approved found a more modest effect, with the drug producing just 2.5% more weight loss than a placebo.

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