Double-blind, randomized, placebo-controlled, multi center trial to evaluate the efficacy and safety of levetiracetam as adjunctive treatment in adult Japanese epileptic subjects with partial onset seizures.

Inclusion Criteria:

• simple and/or complex partial seizures with or without secondary generalization, and first partial seizure >= 2 years before selection visit;
• seizures classifiable according to the ILAE classification;
• minimum of 12 partial seizures per 12 weeks with a minimum of two partial seizures per 4 weeks from the selection visit to the end of the baseline period ;
• exposed to two or more standard AEDs;
• taking up to three of the standard AEDs, at the initiation of the trial.

Exclusion Criteria:

• medication influencing the CNS, except for medication taken for antiepileptic treatment;
• partial seizures uncountable due to clustering, including status epileptics, during the 3 months prior to the selection visit;
• history of cerebrovascular disease including transient ischemic attack (TIA) and progressive cerebral disorder or progressive neurological disorder;
• presence or history of any clinically significant allergic condition and complication or history of significant alcohol abuse or drug abuse in the past.