Substitution has better efficacy than add-on therapy for patients with focal epilepsy after their first antiepileptic drug treatments fail.

Purpose: This study is to compare the efficacy of substitution with add-on therapy in patients with focal epilepsy, whose first monotherapy has failed after receiving usual treatments.

Methods: This is a prospective, long-term, non-randomized observational cohort study. Data were collected from Wenzhou Epilepsy Follow Up Registry Database.