Add-On Therapy of Lamotrigine in Refractory Partial Epileptic Patients Taking Carbamazepine

ABSTRACT

BACKGROUND: Lamotrigne (LTG) is a newly developed antiepileptic drug which has shown to'be effective for medically intractable partial seizures. LTG was recently introduced to Korea but its clinical efficacy has not been investigated yet. METHODS: We assigned 34 medically intractable localization related epileptic patients taking maximally tolerable dose of carbarmazepine(CBZ). The study protocol consisted of 12 weeks of baseline phase, 4 weeks of phase I (drug -adjustment phase) and 8 weeks o f phase II (maintenance of LTG 200mg/day) After phase II, eligible patients entered into long-term therapy. Two patients dropped out during phase II for adverse event (AE) in one, and AE and poor seizure control in the other. RESULTS: Intention to treat analysis of the seizure outcome after 12 weeks of LTG add-on therapy showed mean seizure frequency reduction of 23.6% (p=O.006). More than 50% seizure frequency reduction was seen in 9 of 34 patients (26.4%), which was comparable to the results of previous clinical trials. On the other hand, the incidence of AE were quite high, which was developed in 27 patients. Dizziness with or without blurred vision and/or diplopia were the most common AE and occurred in 64.7%, which improved promptly by either reduction of CBZ or LTG doses. Twenty-two patients entered into long-term therapy and 18 patients showed either maintenance or more. LTG add-on therapy did not show any significant alterations of baseline Lab. Tests. DISCUSSION: LTG was an effective and safe new antiepileptic drug. However, about two-third of our patients developed A. E. similar to CBZtoxicity, which should be carefully considerd for treating patients taking maximally tolerable CBZ therapy. The proportion of patients taking LTG 300mg/day or more was very low in this study, which suggested the racial difference of tolerability to LTG.