Efficacy of levetiracetam in partial seizures.

Controlled clinical trials and routine clinical practice demon-strate that levetiracetam is effective as add-on therapy and appears to allow for withdrawal to monotherapy in patients who respond well in the add-on setting. In pivotal clinical trials of adjunctive therapy with levetiracetam 1000 to 3000 mg/day (pooled data), 40% to 54% of patients experienced a 50% or greater reduction in seizure frequency, compared with 18% to 28% of patients treated with placebo. The median percent reduction from baseline in seizure frequency ranged from 36% to 68% for levetiracetam, versus 10% to 23% for placebo. Seizure freedom was achieved by 11% to 35% of those in the levetiracetam treatment group, compared with 3% to 18% of those in the placebo group. (All comparisons statistically significant versus placebo for simple partial, complex partial, and secondarily generalized seizures except for percentage of seizure-free patients with simple partial seizures.) Clinical obser-vations are consistent with these findings.