Lacosamide add-on Treatment in Refractory Focal Epilepsy: The Experience of a Single Tertiary Center

Objectives: Lacosamide is a third-generation antiepileptic agent that selectively enhances slow inactivation of sodium channels that take part in generation and propagation of action potentials and results in the diminution of neuronal excitability. Because of this new mechanism of action, it is expected to be efficacious in patients with drug-resistant epilepsy. In this study, we aimed to assess the efficacy and tolerability of lacosamide add-on treatment in refractory epilepsy patients by presenting our experience in a tertiary referral center. Methods: Medical records of refractory focal epilepsy patients who were followed in epilepsy outpatient clinic between October 2014 and May 2017 were retrospectively reviewed in this study. Patients who were treated with add-on lacosamide and completed minimum of six months follow-up period were included. >= 50% reduction in seizure frequency was defined as treatment response. Results: In this study, 88 patients were included. The percentage of seizure-free patients after six months follow-up was 4.6% and the treatment response rate was 55.6%. We also evaluated the effect of concomitant use of sodium channel blockers, the presence of abnormal findings on magnetic resonance imaging and the introduction stage of lacosamide. No significant difference was observed in the response rate regarding the mentioned parameters. 19% of the patients reported side effects, the majority of which were dizziness, vertigo and somnolence. None of them discontinued treatment because of side effects. Conclusion: Our findings suggest that lacosamide add-on therapy is effective in refractory focal epilepsy and has an appropriate tolerability and safety profile since none of the patients stopped treatment due to side effects.