<qa>  What is the monohydoxyderivative of oxcarbazepinIn 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. 