Efficacy and safety of levetiracetam 1000-3000 mg/day in patients with refractory partial-onset seizures: a multicenter, open-label single-arm study.

Purpose: To evaluate the efficacy and tolerability of levetiracetam as add-on therapy in patients with refractory partial-onset seizures in a protocol designed to reflect clinical practice.

Methods: All patients in this open-label, single-arm study entered an 8-week baseline period followed by a 4-week titration period and a 12-week maintenance period. Patients initially received levetiracetam 1000 mg/day (administered bid) and could increase to 2000 mg/day after 2 weeks, and to 3000 mg/day after another 2 weeks, to obtain adequate seizure control. During the 12-week maintenance period, the dose of levetiracetam could not be increased but could be decreased once if tolerability warranted. Seizure count and adverse events were recorded by patients in a diary. Quality of life and global evaluation of disease evolution were also evaluated.

Results: Ninety-nine patients were enrolled and 91 completed the study. A steady dose was maintained over the last 8 weeks of treatment or longer in 84 patients, with 89.3% of these patients receiving 3000 mg/day, 9.5% receiving 2000 mg/day, and 1.2% receiving 1000 mg/day. A 35.9% median percent reduction from baseline in weekly frequency of partial-onset seizures was observed over the entire treatment period. The median partial-onset seizure count decreased from 2.3 per week during the baseline period to 1.3 per week over the treatment period. A total of 42.4% of patients were responders (> or = 50% reduction from baseline in weekly seizure frequency) over the treatment period; two patients were seizure-free from the first day of treatment throughout the treatment period. The most frequent drug-related adverse events were fatigue (27.3% of patients), somnolence (11.1%), headache (8.1%), and dizziness (8.1%).

Conclusion: Levetiracetam as add-on therapy at doses up to 3000 mg/day effectively reduced the frequency of partial-onset seizures in patients with refractory epilepsy and was well-tolerated in this study, bridging conditions of placebo-controlled clinical trials and clinical practice.