Efficacy and safety of adjunctive clobazam in Chinese patients with drug-resistant epilepsy: a single-center real-world study

Objective This study evaluated the efficacy and safety of adjunctive clobazam (CLB) in Chinese patients with drug-resistant epilepsy (DRE). Methods We retrospectively included 121 DRE patients receiving adjunctive CLB at the Epilepsy Center of the Seventh Affiliated Hospital of Sun Yat-sen University (Jan 2023-May 2025). Patients were followed at 1, 3, 6, 9, and 12 months or longer. Data collected included epilepsy etiology, seizure type, frequency, treatment duration, dosage, and adverse events. Response was defined as ≥50% reduction in seizure frequency from baseline. Results A total of 121 patients were included (age at medication use 32.4 ± 13.5 years; mean three prior failed antiseizure medications; mean follow-up 12 months). Seizure types were focal (18.2%), generalized (7.4%), and both (74.4%). At first follow-up, 51.2% achieved ≥50% seizure reduction and 39.7% were seizure freedom; at last follow-up, 85.9% responded and 51.6% were seizure freedom. Response rates increased over time (all p < 0.001). Adults had higher response ( p = 0.046) and seizure freedom rates ( p = 0.041) than children. Concomitant oxcarbazepine (OXC) was associated with increased seizure freedom ( p = 0.03), whereas valproate (VPA) was associated with low response rate ( p = 0.013) but not with seizure freedom. Age at medication (OR = 1.032, p = 0.035), CLB dosage (OR = 1.093, p = 0.004), and OXC co-therapy (OR = 2.311, p = 0.04) were independent predictors of seizure freedom. Most common adverse events were somnolence/mental fatigue (9.9%) and hypersomnia (5%). Conclusion Adjunctive CLB significantly reduced seizures in DRE with sustained efficacy. Higher dosage, longer treatment duration, and concomitant OXC use were associated with improved outcomes. CLB showed favorable efficacy, wide applicability, and acceptable safety.