Cannabidiol as Adjunctive Treatment in Drug-Resistant Epilepsy With Epileptic Spasms Beyond Two Years of Age

To assess the efficacy and safety of adjunctive cannabidiol (CBD) in children with drug-resistant epileptic spasms (ES) beyond age 2 years.

We conducted a retrospective longitudinal study of patients with childhood epileptic spasms (CESs) treated with purified CBD (Epidyolex) at Niño Jesus Hospital in Madrid, Spain, from 2020 to 2024. All patients were older than 2 years and had drug-resistant epilepsy and ES as the primary seizure type. Efficacy was assessed by comparing ES frequency before and after CBD treatment, with a good response defined as a ≥50% reduction in ES. Adverse effects (AEs) were recorded to assess safety and tolerability.

Of the 53 patients included, 58.5% achieved a ≥50% reduction in ES frequency, 15% of whom attained complete freedom from ES. Patients with malformations of cortical development and Down syndrome showed the highest response rates. Clobazam was the most frequently associated medication (77.3%), indicating a potential synergistic effect. AEs were reported in 62.2% of patients, with drowsiness, hyperammonemia, and behavioral disturbances being the most common. CBD was discontinued in 17% due to lack of efficacy and in 11.3% due to AEs.

CBD appears to be an effective and well-tolerated adjunctive treatment for drug-resistant ES in children older than 2 years. Significant response rates were found, particularly in patients with Down syndrome and malformations of cortical development. Future studies with larger cohorts and longer follow-up are needed to validate these findings and explore the potential for earlier use of CBD in treatment-resistant epilepsy.