Treatment of bulimia nervosa with topiramate in a randomized, double-blind, placebo-controlled trial, part 1: Improvement in binge and purge measures

Background: This randomized, double-blind, placebo-controlled trial was designed to assess the efficacy and safety of topiramate in bulimia nervosa. Method. Patients with DSM-IV bulimia nervosa were randomly assigned in equal proportions to receive topiramate (N = 35) or placebo (N = 34) for 10 weeks (between April 1999 and Dec. 2000). Topiramate treatment was started at 25 mg/day and titrated by 25 to 50 mg/week to a maximum of 400 mg/day. The primary efficacy measure was mean weekly number of binge and/or purge days. Related outcome measures included mean weekly number of binge days and binge frequency, as well as mean weekly number of purge days and purge frequency. Results: Sixty-four outpatients (33 placebo, 31 topiramate) were included in the intent-to-treat analysis. The median topiramate dose was 100 mg/day (range, 25-400 mg/day). Mean +/- SD baseline number of weekly binge and/or purge days was 5.0 +/- 1.6 for topiramate patients and 5.1 +/- 1.5 for placebo patients. The primary efficacy measure, mean weekly number of binge and/or purge days, decreased 44.8% from baseline with topiramate versus 10.7% with placebo (p = .004). The mean weekly number of binge days decreased 48.2% with topiramate versus 17.7% with placebo (p = .015), and mean binge frequency decreased 49.2% with topiramate versus 28.0% with placebo (p = .071). The mean weekly number of purge days decreased 43.4% with topiramate versus 16.6% with placebo (p = .016), and mean purge frequency decreased 49.8% with topiramate versus 21.6% with placebo (p = .016). Three patients (2 placebo, 1 topiramate) discontinued from the trial due to adverse events. Conclusion: Topiramate was associated with significant improvements in both binge and purge symptoms in this study population and represents a potential treatment for bulimia nervosa.