This study is an open-label, active-controlled,non-inferiority trial comparing efficacy and safety of levetiracetam versus valproate in idiopathic generalized tonic-clonic epilepsy.

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

6 months

1. The decision to choose between two arms of the study was made based on clinicians' judgment and we could not randomized or blind the study.
2. The current results are based on a 6-month follow up of patients and the results in longer follow up periods might be different.
3. The low number of patients might decrease the power of this study.