Medication Combo Improved Weight Loss When Added to Lifestyle Modifications

"Controlled-release phentermine/topiramate was also associated with sustained improvements in the clinical manifestations of weight-related cardiometabolic disease, including hyperglycemia, dyslipidemia and elevated blood pressure, despite reduced use of concomitant medications," the researchers wrote.

The researchers conducted a placebo-controlled, double blind, 52-week extension study in which volunteers continued with the original randomly assigned treatment to complete a total of 108 weeks. The groups received placebo, 7.5 mg phentermine/46 mg controlled-release topiramate or 15 mg phentermine/92 mg controlled-release topiramate. All of the volunteers participated in a lifestyle modification program.

The extension study included 676 participants, and 84% of them completed the study. At week 108, controlled-release phentermine/topiramate was associated with a significant sustained weight loss compared with placebo (P<.0001). For placebo, the mean percentage of body weight change from baseline was –1.8%, vs. –9.3% for the 7.5-mg/phentermine/46-mg topiramate group and –10.5% in the 15-mg phentermine/92-mg topiramate group.

Significantly more participants treated with controlled-release phentermine/topiramate achieved weight loss of at least 5%, 10%, 15% and 20% vs. placebo. Controlled-release phentermine/topiramate also improved cardiovascular and metabolic variables, and decreased rates of diabetes compared with placebo. Controlled-release phentermine/topiramate was well tolerated and associated with reduced adverse event rates between weeks 56 and 108 compared with weeks 0 to 56.

"The unmet clinical need for effective weight-loss medications, together with the favorable risk–benefit profile in the current study, suggests that controlled-release phentermine/topiramate in conjunction with a lifestyle-intervention program could be a valuable therapeutic approach to counteract increasing rates of obesity and its related complications," the researchers wrote.

Garvey WT. Am J Clin Nutr. 2011;doi:10.3945/ajcn.111.024927.