Clinical Question

Are weight-loss medications effective for the long-term treatment of obesity?

Bottom Line

This review of commonly used weight-loss medications, including orlistat (Xenical), lorcaserin (Belviq), phentermine/topiramate (Qsymia), bupropion (Wellbutrin), metformin (Glucophage), and zonisamide (Zonegran), reported an average weight loss for participants of 2.5 to 8.0 kg (5.5 to 17.5 lb) relative to placebo after one year of therapy, with improvements noted in cardiovascular risk factors, including reduced lipid, glucose, and blood pressure levels. However, there is no evidence yet that any of these treatments have improved patient-oriented cardiovascular outcomes, including reduced morbidity or mortality. (Level of Evidence = 1a–)

Synopsis

These investigators searched clinicaltrials.gov and PubMed, and examined expert recommendation reports and bibliographic references of included studies for English language–only randomized controlled clinical trials. The trials must have lasted at least one year with at least 50 participants per group at baseline, and must have had a 50% retention rate or better. Studies meeting eligibility criteria included 15 trials of orlistat (N = 9,561), three trials of lorcaserin (N = 6,638), and two trials of phentermine/topiramate (N = 3,544), all compared with placebo. Phentermine is the most widely prescribed obesity medication in the United States, but there are no clinical trials evaluating outcomes of monotherapy at 12 months or longer. Other medications studied included bupropion, metformin, and zonisamide. Participants lost an average of 2.5 to 8.0 kg relative to placebo, with significant improvements noted in cardiovascular risk factors, including lowered lipid, glucose, and blood pressure levels. However, none of the medications have been shown to improve patient-oriented cardiovascular outcomes, including reduced morbidity or mortality.

Study design: Systematic review

Funding source: Foundation

Setting: Various (meta-analysis)

Reference: YanovskiSZYanovskiJALong-term drug treatment for obesity: a systematic and clinical review. JAMA.2014; 311( 1): 74– 86.