MedWire News: Findings from a meta-analysis published in the British Medical Journal have clarified the benefits and drawbacks of the anti-obesity therapies orlistat, sibutramine, and rimonabant.

"Orlistat, a gastrointestinal lipase inhibitor, sibutramine, a centrally acting monoamine reuptake inhibitor, and rimonabant, an endocannabinoid receptor antagonist, are approved for the long-term treatment of obesity," explain Raj Padwal (University of Alberta, Edmonton, Canada) and colleagues.

Predicting that the use of these medications will increase in the future, Pawal et al thought it timely to collate data on their safety and efficacy.

A search of the major scientific databases uncovered 30 randomized, double-blinded trials of 1-4 years duration that were performed in adults. Specifically, 16 trials used orlistat in a total of 10,631 patients, 10 trials used sibutramine in 2623 patients, and four trials used rimonabant in 6365 patients.

The meta-analysis confirms that orlistat, sibutramine, and rimonabant all reduce weight to a significantly greater degree than placebo, with average decreases of 2.9 kg, 4.2 kg, and 4.7 kg, respectively.

Orlistat also reduced levels of total and low-density lipoprotein cholesterol and the incidence of diabetes, but was associated with an increased incidence of gastrointestinal side effects and slightly reduced levels of high-density lipoprotein cholesterol.

Similarly, sibutramine lowered concentrations of high-density lipoprotein cholesterol and triglycerides but raised blood pressure and pulse rate.

Rimonabant increased high-density lipoprotein cholesterol levels, decreased triglyceride concentrations and blood pressure, and improved glycemic control in patients with diabetes, but also increased the risk for mood disorders.

The authors say that findings from ongoing trials into the effects of anti-obesity drugs on cardiovascular morbidity and mortality should inform future use of the mediations.

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