Abstracts

Objectives Zonisamide (ZNS) is a newly approved antiepilepsy drug (AED) indicated for the adjunctive treatment of partial seizures in adults. During developmental studies, we noted an apparent trend toward weight loss in patients taking ZNS. We subsequently followed 23 patients taking ZNS for periods of 2 to more than 58 months to observe potential changes in body weight. Methods Patient weights and ZNS doses were recorded on a visit-by-visit basis. Body weight and ZNS dose data were available for 13 patients receiving ZNS for > 14 months. Data were available for 10 patients receiving ZNS for 2 to < 14 months. Results Fifteen of 23 patients (65%) experienced a weight loss of 4 - 11% of total body weight from baseline to final visit. Three patients had weight losses of > 10%. Two patients had a weight loss of 1%, one patient's weight was unchanged, and five patients experienced small weight gains of 1 - 3.5%. In six patients, weight loss was apparent at month two; in two of these patients their weights had returned to baseline at the final visit (month 58). In one patient, an early weight gain was followed by a substantial 16% weight loss between months 21 and 28, not accompanied by any change in ZNS dose. ZNS doses ranged from 200 - 700 mg/day. Although there was no clear association between ZNS dose and weight loss, two of the three patients experiencing a weight loss of > 10% were on final ZNS doses of 600 mg/day, while the third was on 700 mg/day. (The third patient had received 750 - 800 mg/day from month 26 through month 50.) Conclusions Although statistical analyses were not performed, these data support earlier observations that ZNS is associated with weight loss in some patients. While drug-related weight loss is considered to be an adverse event, many patients do not consider it a problem to be reported. However, in patients already below their ideal weights a further loss of 10% may be a problem. Therefore, patient baseline weight should be considered when selecting candidates for ZNS therapy. Weight should also be monitored throughout the course of therapy and patients on ZNS should be counseled to maintain a healthy diet with adequate caloric intake.