Zonisamide was well tolerated and useful for a variety of seizure types -- and may be appropriate as first line therapy, noted Dean K. Naritoku, MD, associate chair, neurology division, Southern Illinois University, Springfield, Illinois, United States. Dr. Naritoku and colleagues conducted the chart review of 123 adult and paediatric patients receiving zonisamide monotherapy.

Patients enrolled in the study had at least 2 partial-onset seizures (complex or secondarily generalised) or 1 seizure and an abnormal electroencephalogram. They were randomised to zonisamide monotherapy at 25, 100, and 300 mg per day. The total treatment duration was up to 42 weeks.

The primary efficacy measure was the time from the first dose of zonisamide to the occurrence of 2 complex partial seizures or 1 generalised tonic-clonic seizure.

The study excluded patients with a history of status epilepticus or simple partial seizures only, as well as patients with a history of nonepileptic seizures or progressive central nervous system disease.

Although there were no significant differences between the groups, patients in the 300-mg/day group took a longer time to reach the exit criterion than patients in the 25- and 100-mg/day groups. Also, 50.8% of patients in the 300-mg/day group remained seizure-free for at least 6 months versus 33.9% in the 25-mg/day group and 30.8% in the 100-mg/day group (P =.061).

Patients in the higher-dose group were more likely to drop out of the study prematurely because of side effects.

Zonisamide is a newer anti-epileptic drug approved for use in the United States, Japan, and Europe as adjunctive therapy for refractory partial seizures in adult patients. The drug exerts its anticonvulsant effect through multiple mechanisms of action and possesses several favourable pharmacokinetic traits, including linear pharmacokinetics. The efficacy and safety of zonisamide as adjunctive therapy in refractory partial seizures among adult patients have been demonstrated in pivotal trials.

This study was conducted at 34 sites in the US, Mexico, and Europe. Funding was provided by Eisai, Inc.


[Presentation title: Dose Response, Safety, and Efficacy of Zonisamide as Monotherapy in Patients With Newly Diagnosed Epilepsy. Abstract P01.111]

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