Evaluation of Lamotrigine in Subjects With Absence Seizures

This is an open-label study evaluating the efficacy and safety of lamotrigine (LTG) for the treatment of newly-diagnosed typical absence seizures. Subjects will be children and adolescents < 13 years of age. It will be conducted at multiple sites in the US. The study will consist of 4 phases: Screen Phase (up to 1 week), Baseline Phase (24 hours), Escalation Phase (up to 20 weeks) and Maintenance Phase (12 weeks). Subjects will receive increasing doses of LTG according to the dosing schedule until attaining seizure freedom as confirmed by hyperventilation (HV) for clinical signs and a 1-hr EEG at 2 consecutive weekly visits. At that point, subjects will move into the 12-week Maintenance Phase. Subjects who do not achieve seizure freedom upon reaching the maximum dose (10.2mg/kg/day) with the specified dose escalation will be discontinued from the study. During the Maintenance Phase, the investigators will use their best effort to maintain the subjects at the efficacious dose reached. If the subjects have unacceptable side effects or inadequate seizure control, the doses of study drug can be increased or decreased as specified in the dosing schedule. Safety will be assessed by monitoring adverse events, laboratory assessments, and serum lamotrigine levels. Health outcomes assessments will also be conducted.