Time-dependent retention and discontinuation of eslicarbazepine acetate treatment in real-world focal epilepsy: The first three months as a key period.

PURPOSE: Eslicarbazepine acetate (ESL) is a widely used anti-seizure medication (ASM), used as monotherapy or adjunctive therapy for patients with focal epilepsy, including drug-resistant epilepsy. Detailed analyses of factors associated with treatment outcomes are limited; therefore, this study evaluated 12-month retention, responder, and seizure freedom rates, focusing on time-specific associated baseline characteristics. METHODS: This single-centre, retrospective, observational study included patients (≥19 years) with focal epilepsy who initiated ESL treatment from November 2022 to December 2024. Treatment efficacy was evaluated by retention, responder (≥50% seizure reduction compared with baseline) and seizure freedom rate at 3, 6, and 12 months. Tolerability was assessed based on adverse events reported by patients. RESULTS: In 12-month analysis cohort (n = 180; mean age 48.5 ± 15.9 years; 50.6% men), the retention rate was 69.4%. Of 210 patients initiating ESL, 85 (40.5%) had non-retention or unavailable follow-up; 62 cases (72.9%) occurred within first 3 months. Adverse events were most common. A higher retention rate was associated with epileptiform discharge on electroencephalogram, whereas a lower retention rate was associated with baseline seizure frequency. Most reported adverse events occurred within 3 months of ESL initiation (74.4%). More adverse events were associated with concomitant ASM use, particularly lacosamide and lamotrigine. The five most common adverse events were constant at 3, 6, and 12 months. CONCLUSION: The first 3 months are a key period for optimizing treatment retention and minimizing adverse events. Careful consideration of concomitant ASM is required, as concomitant ASM may be associated with lower retention and more adverse events, particularly sodium channel blockers.