Zonisamide is used in combination with other anticonvulsants in the management of partial seizures in adults with epilepsy.
Efficacy of zonisamide as adjunctive therapy was established in 3 multicenter, placebo-controlled, double-blind clinical trials in patients who had refractory partial onset seizures with or without secondary generalization while receiving a regimen of 1 or 2 anticonvulsants and had experienced at least 4 partial seizures during each month of the baseline period. In one study, patients received either placebo or 400 mg of zonisamide daily (200-mg doses given twice daily) for 5 weeks after a 7-week titration period. In the other 2 studies, patients received either placebo or 400-600 mg of zonisamide daily (given in 1 or 2 daily doses; average maintenance dosages were either 530 or 430 mg daily) for about 8 weeks after a 4-week titration period. More patients receiving zonisamide experienced a reduction in seizure frequency of 50% or greater compared with baseline (i.e., responder rate) compared with placebo-treated patients. The efficacy of zonisamide reportedly is not affected by age, gender, or race.