Drug safety evaluation of zonisamide for the treatment of epilepsy

INTRODUCTION: Zonisamide is a broad spectrum antiepileptic drug with multiple mechanisms of action which has been recently approved in the US and Europe as an adjunctive therapy for refractory partial seizures in adults. AREAS COVERED: The adverse effect profile of this drug from controlled, randomized studies and open and long-term studies and case reports is described herein. EXPERT OPINION: Zonisamide has several CNS dose-dependent, metabolic and idiosyncratic adverse effects. Knowledge of these effects is essential for the prevention or minimization of several of them. For example, treatment-emergent adverse events may be prevented by slow titration; incidence of kidney stones may be reduced through an increase in fluid intake and avoidance of concomitant treatment with topiramate and/or ketogenic diet; and oligohydrosis may be prevented by hydratation and avoidance of hot temperatures. An accurate selection of patients can be useful for the prevention of some adverse effects. Psychiatric disturbances are mainly observed in predisposed subjects and patients with a previous allergic episode to sulfonamide-containing drugs are at a higher risk for developing a skin rash.