Background: Lacosamide (LCM) is a novel anti-epileptic drug (AED) that enhances the slow inactivation of voltage-gated sodium channels. Randomised placebo controlled trials in adults with LCM as an adjunctive therapy with partial seizures report improved 50% responder rates (>50% reduction in seizure frequency) compared to placebo (RR=1.68)^1. However, there is limited data on its efficacy and tolerability in children with refractory focal epilepsy (RFE).

Objective: In a single center audit, we aimed to assess efficacy and tolerance of LCM as add-on therapy in childhood RFE.

Methods: Efficacy was evaluated at 12 weeks after initiating LCM. Adequate Response (AR) was defined as ≥ 50% reduction in seizure frequency and partial response (PR) as >25% but <50% improvement. Poor response was defined as LCM discontinuation either due to inadequate seizure control (<25% reduction) or increasing seizure frequency.

Results: 23 children with RFE (multiple AED trials -all, previous epilepsy surgery-3,  VNS-1) were included. The median age at initiation of LCM was 13.5 years (IQR, 7.5-15). An adequate response was observed in 3/23(13%) and a partial response in 5/23(22%). 15/23 (65%) had a poor response. The median dose was 6.8mg/kg, (IQR, 5.5-8) LCM was well tolerated in the majority, with minor side effects: drowsiness (17%) and mood change (8%).

Conclusion: LCM was well tolerated in children with RFE but appeared to have  limited efficacy, achieving an adequate or partial response in one-third.