Dramatic weight loss with levetiracetam

Background: Levetiracetam is considered a weight-neutral drug. We report 19 cases of significant weight loss associated with levetiracetam at a dose ranging from 500 to 2000 mg/day. Methods: The population was divided into two groups. Group 1 includes patients in whom levetiracetam was the only possible cause of weight loss and Group 2 those in whom other factors may have played a role. Similar cases reported by the French national drug safety center were added (Group 3). Results: Group 1 included 9 females and 3 males (weight loss ranging from 8.1% to 28.6%). Three patients had levetiracetam in monotherapy. Prior levetiracetam only three were overweight. One patient was hospitalized for a thorough assessment of weight loss. Seven patients reported reduced caloric intake due to decreased pleasure with food. The other five did not report any changes in feeding behavior. Group 2 included seven females with a weight loss ranging from 10% to 26.6%. One patient was on topiramate since two years prior to levetiracetam. Weight loss started with the introduction of levetiracetam. In 4 patients, there was a decreased dosage or cessation of a previous drug known to produce weight gain in some cases simultaneously to the introduction of levetiracetam, but in two of these patients these drugs had not produced any weight gain. Group 3 included only two patients (weight loss: 7 and 20 kg). Conclusions: This study provides evidence that levetiracetam can cause significant weight loss. Women are at higher risk while initial weight is not a factor.