Efficacy and Safety of Lacosamide in Adolescents with Lennox-Gastaut Syndrome

Purpose: We aimed to assess the efficacy and safety of lacosamide in Korean adolescents with Lennox-Gastaut syndrome (LGS), especially in those who concomitantly used other sodium channel blockers (SCBs). Methods: We retrospectively reviewed the medical records of adolescents with LGS who initiated lacosamide from ages 16 to 18. The efficacy of lacosamide was evaluated by seizure frequency before and after lacosamide trial. Safety was assessed by lacosamide-related adverse events, consequent dosage titration, and titration effects. We compared the efficacy and safety of lacosamide according to concomitant use of other SCBs. Results: In 26 eligible adolescents with LGS, the median age of seizure onset was 2.0 years, and the median age of lacosamide initiation was 17.1 years. At the time of lacosamide initiation, the median number of concomitant antiepileptic drugs was 4, and 23 patients (88%) had tried dietary, surgical, or neuromodulatory therapies. Patients were on lacosamide for a median of 13.5 months with a median maximal dosage of 8.1 kg/mg/day. After lacosamide trial, 11 patients (42%) had an over 50% reduction of seizures. Six patients (23%) had lacosamide-related adverse events. The percentage of patients on concomitant SCBs was higher among non-responders (10 of 15, 67%) than among responders (6 of 11, 55%). Patients taking concomitant SCBs had a higher ratio of adverse effects (5 of 16, 31%) than their counterparts (1 of 10, 10%). Conclusion: Lacosamide is an effective and tolerable antiepileptic drug in adolescents with LGS. Concomitant SCB use may lead to less effective treatment and more adverse events.