Short-term topiramate treatment does not improve insulin sensitivity or secretion in obese insulin-resistant women

ObjectiveLong-term treatment with topiramate reduces body weight and improves insulin sensitivity in obese humans. Our aim was to evaluate the effect of topiramate treatment for 4 weeks on insulin sensitivity and secretion, independent of weight loss.DesignRandomized, double-blind, crossover, placebo-controlled study.MethodsThirteen obese (BMI 36.6±1.3 kg/m2 (mean±s.e.m.)), insulin-resistant (homeostasis model of assessment-insulin resistance 2.0±0.2) women received topiramate (T, maximum dose of 75 mg) and placebo (P) for 4 weeks, separated by a 4-week washout period. Insulin sensitivity and β-cell function were assessed using a two-step hyperinsulinemic euglycemic clamp with stable isotopes and a hyperglycemic clamp.ResultsHepatic and peripheral insulin sensitivities were not affected by topiramate treatment (glucose disposal rate (step 1 (insulin infusion rate 10 mU/m2 per min) T: 17.5±0.8 vs P: 18.5±1.0 μmol/kgLBM per min, t=1.016, P=0.33; step 2 (insulin infusion rate 40 mU/m2 per min) T: 27.9±3.2 vs P: 28.8±1.9 μmol/kgLBM per min, t=0.418, P=0.68)). Subjects lost a small amount of weight during the topiramate period (T: −1.0±0.2 vs P: −0.1±0.2 kg, t=2842, P=0.15). There were no changes in body fat mass, blood pressure, and fasting glucose. β-Cell function was not affected by topiramate as evidenced by an unaltered area under the curve of early (0–10 min; T: 1929.6±265.7 vs P: 2024.7±333.6 pmol/l, t=−0.357, P=0.73) and late (80–120 min; T: 28 017.7±5029.9 vs P: 31 567.7±5376.2 pmol/l, t=−1.481, P=0.16) phase insulin levels during hyperglycemia. The use of topiramate was associated with significant side effects such as paresthesia, nausea, dizziness, and concentration problems.ConclusionsLow-dose topiramate treatment for 4 weeks, relative to placebo, had no significant effect on insulin sensitivity in overweight/obese adult females without established diabetes.