Zonisamide In Parkinson's Disease

Zonisamide, a widely available antiepileptic drug, has been approved in Japan as adjunctive therapy with levodopa for the treatment of previously treated patients with Parkinson's disease. It is an oral 1,2-benzisoxazole-3-methanesulfonamide and is associated with increased striatal dopamine levels in animal models. In two 12-week, randomized, double-blind, multi-centre trials in adult patients with inadequately controlled Parkinson's disease and receiving levodopa, zonisamide 25 mg once daily (the recommended dosage) significantly improved motor function from baseline at final assessment, as assessed by the Unified Parkinson's Disease Rating Scale (UPDRS) Part III total score (primary endpoint), compared with placebo. Zonisamide 25 mg once daily as adjunctive therapy with levodopa was generally well tolerated by patients with Parkinson's disease. The overall incidence of adverse events was not significantly different between zonisamide 25mg once daily and placebo groups in the phase IIb/III trial.