Levetiracetam Versus Valproate in Idiopathic Generalized Tonic-clonic Seizures

Inclusion Criteria: * Age≥16 * At least 2 unprovoked generalized tonic-clonic seizures in last 2 years with at least one in last 6 months * Normal brain MRI or MRI without epileptogenic lesion * Normal electroencephalography(EEG) or existence of generalized epileptiform discharges without any focal epileptiform discharges. * Signing consent form Exclusion Criteria: * History of treatment by sodium valproate or levetiracetam * History of treatment by any anti-epileptic drug in last 6 months * Plan for pregnancy * Using no certain contraceptive method * History of past or current hepatic disease * History of past or current renal disease * History of past or current hematologic disease * History of known psychiatric disease * History of status epilepticus