Drugs to treat obesity: do they work?

Obesity is a disease that has historically eluded effective medical therapy. Prior to 2012, phentermine and orlistat were the only medications available to treat obesity in the USA, with phentermine approved only for short-term use. However, as of 2015, the repertoire of pharmacological agents available to treat obesity has greatly expanded to include four new drugs: lorcaserin, phentermine/topiramate extended release (ER), naltrexone ER/wellbutrin ER and liraglutide. Each has a unique mechanism of action and all are intended for long-term use. These newer medications share a common strategy to promote weight loss in that they are designed to manipulate the control of hunger and satiety in the central nervous system. Interestingly, the majority of these new agents are combinations of older medications that have been used for conditions other than obesity. The amount of weight loss seen with these agents beyond placebo varies but generally falls in the range of 3-10% of starting weight and requires continual use of the drug in order for weight loss to be sustained. In addition, each drug has a unique side effect profile that should be carefully considered when selecting the best agent for a given individual. This article provides a review of these recently approved medications focusing on efficacy, side effect profiles and appropriate application to the individual patient.