Researcher Siddharth Singh of the University of California, San Diego, and his colleagues conducted 28 randomized clinical trials with just over 29,000 participants. The median age was 46 years old, about three-quarters of the participants were women with a median weight of 222 pounds and a median body-mass index of 36.1.
Patients who took Vivus's Qsymia, which contains phentermine-topiramate, stood the highest chance of losing a significant amount of weight, and lost the most pounds on average. That was followed by Novo Nordisk's drug Saxenda, Orexigen's Contrave drug, Arena's drug Belviq and orlistat, sold as Xenical by Roche and over the counter by GlaxoSmithKline in the United States and United Kingdom.
The study also noted that participants on Saxenda and Contrave were the likeliest to discontinue their treatment after an adverse event, which is a side effect that was significant enough to merit stopping the treatment.
The authors did include a note of caution in their study, warning that ultimately, "given the differences in safety, efficacy, and response to therapy, the ideal approach to weight loss should be highly individualized, identifying appropriate candidates for pharmacotherapy, behavioral interventions, and surgical interventions.
In addition to the drugs that were studied by these researchers, patients have other alternatives to weight loss, including a controversial device that pumps food out of a person's stomach to cut calories that was approved by the FDA earlier Tuesday. The device, known as AspireAssist, is made by Aspire Bariatrics.
Despite rising levels of obesity, many doctors hesitate before prescribing weight-loss drugs due to "concerns regarding the long-term safety profile" of these drugs, the authors wrote. They added, patients may not seek them out for the same reason.
An article in trade publication Pharmacy Times published in April noted that hardly any obese Americans are taking any of the FDA-approved weight loss drugs, including the ones listed here.