The effect of topiramate on energy balance in obese men: a 6-month double-blind randomized placebo-controlled study with a 6-month open-label extension.

Author: Tremblay A, Chaput JP, Berube-Parent S, Prud'homme D, Leblanc C, Almeras N, Despres JP

Author affiliation: Division of Kinesiology (PEPS), Department of Social and Preventive Medicine, Laval University, G1K 7P4, Quebec, Canada, angelo.tremblay@kin.msp.ulaval.ca.

Publication date & source: 2007.02, Eur J Clin Pharmacol., 63(2):123-34. Epub 2007 Jan 3.

OBJECTIVE: Topiramate (TPM) has been reported to reduce body weight beyond a placebo in the treatment of obese participants, but the effect of this agent on components of energy balance has not yet been established in humans. Thus, the aim of this study was to study the impact of TPM on food preferences, measures of satiety, food intake, resting metabolic rate (RMR), and 24-h energy expenditure. METHODS: The study design consisted of a 6-month, single-center, randomized, double-blind, parallel group, placebo-controlled trial with a 6-month open-label extension. The study included 68 sedentary men with abdominal obesity (waist circumference >/=100 cm), of between 25 and 55 years of age, with a dyslipidemic profile and a body mass index (BMI) >/=27 and </=40 kg/m(2). RESULTS: Treatment with TPM produced significant changes in anthropometric variables and body composition compared with placebo. However, at the end of the 1-year study, the placebo/TPM group showed similar weight loss and reduction in body fatness compared with the TPM/TPM group. For instance, at the end of the 12-month intervention, mean percentage of body weight loss from baseline was about -5% in both groups (-4 kg fat loss). Topiramate treatment reduced energy intake, be it in the context of an ad libitum buffet-type meal or under free living conditions. The 24-h daily energy expenditure (DEE) assessed by whole-body indirect calorimetry adjusted for body weight and age was not altered by TPM treatment. CONCLUSION: Topiramate treatment produced significantly greater weight loss than placebo and the majority of this loss was explained by a decrease in body fat stores. Most of the weight loss effect produced by TPM therapy was observed within a period of 6 months. Finally, TPM treatment had an impact on energy balance through a reduction in food intake that appears to have created an energy deficit of about 30,000-40,000 kcal compared with treatment with the placebo over 6 months.