Influence of age and antiepileptic comedication on lacosamide concentrations in children with epilepsy: A retrospective cohort study.

OBJECT: To explore the influencing factors of lacosamide serum concentration in children with epilepsy, and to provide evidence-based guidance for individualized dosing strategies. METHODS: Clinical data of pediatric epilepsy patients treated with lacosamide from September 2021 to January 2025 were retrospectively analyzed. Participants were stratified by age into ≤6, 6-12, and >12 years groups. Non-parametric tests were employed to compare differences in daily dose, weight-adjusted daily dose, serum concentration, and concentration-to-dose ratio (CDR) across sex, age, and concomitant antiepileptic drugs (AEDs) groups. Multiple linear regression analysis was conducted to identify independent factors influencing serum concentration. RESULTS: The study enrolled 438 patients (boys: 261, 59.59%; girls: 177, 40.41%), with age distribution as follows: ≤ 6 years (n = 85, 19.41%), 6-12 years (n = 294, 67.12%), and >12 years (n = 59, 13.47%). The > 12 years group exhibited significantly higher daily dose, weight-adjusted daily dose, and CDR compared to younger cohorts. Concomitant use of non-hepatic enzyme-inducing AEDs resulted in elevated serum concentration and CDR relative to lacosamide monotherapy. Regression analysis identified body weight, weight-adjusted daily dose, and coadministration of non-hepatic enzyme-inducing AEDs as independent predictors of serum concentration. CONCLUSION: Age and concomitant non-hepatic enzyme-inducing AEDs therapies significantly influence lacosamide exposure, underscoring the necessity for age-based dynamic dose optimization and rigorous evaluation of polypharmacy regimens to achieve precision therapeutics.