The results of a small study published in the November issue of the Journal of Clinical Psychiatry suggest that topiramate may have a long-term therapeutic effect in some patients with binge-eating disorder (BED) associated with obesity.

Dr. Susan L. McElroy, of the University of Cincinnati College of Medicine, Ohio, and colleagues examined the long-term effectiveness of topiramate, a novel anticonvulsant, in 61 patients with BED and obesity. The subjects were enrolled in a 14-week, randomized, double-blind, placebo-controlled trial. Of these, 31 completers were included in a 42-week, open-label extension trial of topiramate.

Of the 31 patients in the open-label extension study, 15 received topiramate and 16 received placebo.

“Topiramate was titrated from 25 mg/day to a maximum of 600 mg/day,” the researchers report. The main outcome measure was the change in weekly binge frequency from baseline to final visit using the last observation carried forward for patients who received topiramate.

For patients receiving double-blind topiramate, baseline was the beginning of the controlled study. Baseline for placebo patients was the beginning of the open-label trial.

A total of 44 patients (31 who received topiramate in the open-label trial and 13 who took topiramate in the double-blind study only) received at least one dose of topiramate. Outcome measures at a median final dose of 250 mg/day were available for 43 patients.

All 43 patients experienced a significant decline in mean weekly binge frequency from baseline to final visit (-3.2; p < 0.001). Mean weekly binge frequency also declined significantly for the 15 patients who received topiramate only during the open-label trial (-2.5; p = 0.044) and the 15 who took topiramate during the controlled and open-label studies (-4.0; p < 0.001).

The team observed a significant reduction in body weight.

A total of 35 patients discontinued topiramate, including 14 during the controlled study and 21 during the extension trial. The most common reasons for discontinuation were protocol nonadherence and adverse events.

“Controlled trials of topiramate in the long-term treatment of BED appear warranted,” Dr. McElroy’s group concludes. “However, such trials should address potentially high attrition rates and consider fixed-dose designs to establish the minimally effective and maximally tolerated doses of topiramate in the treatment of this disorder.”

J Clin Psychiatry 2004;65:1463-1469.