The efficacy profile of the drug has been established through three pivotal randomized double blind, placebo controlled, parallel studies on 904 patients suffering from partial seizures secondarily or not generalised that were not well controlled by previous treatment (Shorvon et al. 2000; Ben-Menachem et al. 2000; Cereghino et al. 2000).In these three studies LEV showed a significant reduction of seizure frequency. A pooled analysis of the results from these three studies supports a dose-response effect for levetiracetam: responder rates were 28.5, 34.3 and 41.3 % for patients treated with levetiracetam 1000, 2000, 3000 mg/day respectively, as compared with 13.1% for placebo group. The respective values for complete seizure freedom were 4.7, 6.3, 8.6 and 0.8%(Privitera 2002, Boon et al, 2002).