 In both the test and the control allocations, two further blood samples for the determination of the serum levels of the AEDs will be collected again 4 days later 5 days later for patients remaining on randomized treatment for 5 days, one two hours after the evening dose absorptive phase sample on day 5 day 6 for patients remaining on randomized treatment for 6 days and one in the next morning day 6 or 7 just prior to the morning dose trough sample. Care will be taken to ensure that the samples on days 5 and 67 be collected at the same times, not only in relation to times of dosing but also in relation to actual time of the day and meal times. A 4-day interval for the post-randomization pharmacokinetic assessment is sufficient to reach steady state for AEDs with expected half-lives of about 12 h or less carbamazepine, levetiracetam, valproic acid, topiramate combined with enzyme inducers, lamotrigine combined with enzyme inducers, and the monohydoxyderivative MHD of oxcarbazepine, for which oxcarbazepine is a prodrug. Likewise, a 5-day interval is sufficient to reach steady state for AEDs with expected half-lives of about 24 h lamotrigine and topiramate not combined with enzyme inducers, and lamotrigine combined with both enzyme inducers and valproic acid. 