Objective: To evaluate the efficacy and safety of 500 mg bid and 1500 mg bi
d levetiracetam as adjunctive therapy for refractory partial seizures in a
double-blind, randomized, placebo-controlled, parallel-group, multicenter t
rial. Methods: The authors studied patients with uncontrolled partial seizu
res (minimum 12 per 12 weeks), regardless of whether they became secondaril
y generalized, for 38 weeks. A 12-week baseline was followed by random assi
gnment to adjunctive therapy with placebo (n = 95), levetiracetam 1000 mg/d
ay (n = 98), or levetiracetam 3000 mg/day (n = 101). Upward titration over
4 weeks was followed by 14 weeks of fixed dose treatment, and concluded wit
h an 8-week medication withdrawal period or entering a follow-up study. Res
ults: Of 294 patients randomized, 268 completed the study. Partial seizure
frequency during the entire evaluation period (primary efficacy variable) w
as lower with levetiracetam compared to placebo (p less than or equal to 0.
001 for both groups). More patients responded (defined as minimum 50% reduc
tion in partial seizure frequency) to levetiracetam than placebo, with rate
s of 33.0% in the 1000 mg/day and 39.8% in the 3000 mg/day group, compared
to 10.8% in the placebo group (p < 0.001). Of 199 patients receiving leveti
racetam, 11 became seizure free; no patient became seizure free in the plac
ebo group. Treatment-emergent adverse events (greater than or equal to 10%)
, mostly mild to moderate in severity, with incidences higher than placebo
were asthenia, dizziness, flu syndrome, headache, infection, rhinitis, and
somnolence. Conclusion: Adjunctive therapy with levetiracetam was effective
and well tolerated in controlling partial seizures.