Zonisamide in the treatment of bulimia nervosa: an open-label, pilot, prospective study.

To assess preliminarily the effectiveness of zonisamide in bulimia nervosa. This was an open-label, prospective, 12-week, flexible dose study of zonisamide in bulimia nervosa. The primary outcome was binge-purge episode frequency. Twelve individuals received zonisamide, 10 completed at least one post-baseline evaluation, and six completed the study. Mean dose at endpoint was 420 (SD = 215) mg/day. Zonisamide was associated with significant reductions in frequency of binge-purge episodes and binge-purge days as well as measures of binge eating behavior, purging behavior, clinical severity, obsessive-compulsive features, and depressive symptoms. Weight was unchanged. In this open-label trial, zonisamide was effective in bulimia nervosa, but associated with a high discontinuation rate.