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A New, but Not Yet Approved, Weight Loss Drug

A new serotonergic drug appeared to be safe in this study.

The weight loss drugs fenfluramine and dexfenfluramine were removed from the U.S. market in 1997. These drugs were agonists of serotonin receptors located not only in the central nervous system (CNS; where the drugs suppressed appetite), but also in heart valves and pulmonary arteries (where the drugs caused valvulopathy and pulmonary hypertension). In contrast, a new serotonin receptor agonist, lorcaserin, is highly selective for CNS receptors.

In an industry-sponsored randomized trial, 3182 obese or overweight adults received lorcaserin or placebo, along with dietary and exercise counseling. People with diabetes or psychiatric disease were excluded. Only half the patients completed 1 full year in the study.

At 1 year, mean weight loss was significantly greater in the lorcaserin group than in the placebo group (5.8% vs. 2.2% decrease from baseline weight); the proportion of patients with >5% weight loss was also higher with lorcaserin than with placebo (48% vs. 20%). After 1 year, patients in the lorcaserin group were re-randomized to further active drug therapy or to placebo; at 2 years, those who received continuous lorcaserin were more likely to maintain weight loss than those who were switched to placebo. Serial echocardiography showed no evidence of cardiac valvulopathy.

Comment: Lorcaserin has been submitted for FDA approval. Although it seemed to be safe and moderately effective in this study, the high dropout rate is an important caveat. If lorcaserin is approved, careful postmarketing surveillance will be essential, given the checkered history of serotonergic weight loss drugs.

— Allan S. Brett, MD

Published in Journal Watch General Medicine July 29, 2010

Citation(s):

Smith SR et al. Multicenter, placebo-controlled trial of lorcaserin for weight management. N Engl J Med 2010 Jul 15; 363:245.

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Reader Remarks:

Review and add to remarks on this article

• Safe Diet Pills
  William Steinsmith, MD, 30 Jul 2010 1:00 PM EST
  Dextroamphetamine remains the bariatric gold standard and rational drug of choice. Among the many subversions of the rational pharmacopeia engendered... [more]
• Weight Management
  J Ross Hester, PA-C) ret. CH, Edcom Associates Holistic Health Mt Dora, FL, 30 Jul 2010 1:00 PM EST
  As a Psychiatric PA who was originally hired, years ago, because my preceptor wanted to expand his practice to more... [more]
• ?worth it
  Rocco Arcieri, DMA, York, 3 Aug 2010 12:42 PM EST
  Obviously several questions. At a 5.8% reduction in weight from baseline, will this drug be worth the price for a... [more]

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