Objectives: To evaluate efficacy and safety of oxcarbazepine (OXC) as add-on therapy in Thai refractory epileptic patients.
Material and Method: A randomized, double-blind clinical trial was conducted in outpatients of the Epilepsy Clinic of Phramongkutklao Hospital. OXC in the doses of 600 or 1200 mg/d were added to 39 refractory epileptic patients with the median baseline seizure frequency of at least 2 per 28 days.
Results: Of 35 patients who completed the 98-day treatment period, 4 became seizure free. A reduction in median seizure frequency of 47% and 58% was observed in patients in the 600 and 1,200 mg OXC/d groups, respectively. Among them, 44% and 53% demonstrated ≥ 50% reduction in median seizure frequency. About 85% of patients in each group reported one or more mild to moderate adverse events.
Conclusion: OXC in the doses of 600 and 1200 mg/d appear to be safe and effective as adjunctive therapy in Thai refractory epileptic patients. Further studies are needed to confirm its long-term efficacy and tolerability.

Keywords: Partial seizure, Oxcarbazepine, Antiepileptic drug, Add-on therapy