Effectiveness and Safety of Cannabis-Based Products for Refractory Epilepsy From Real-World Evidence

Cannabis-based products have emerged as a potential therapeutic option for refractory epilepsy; however, real-world evidence remains limited, particularly within public health systems. This study evaluated the effectiveness and safety of cannabis-based products among patients with refractory epilepsy treated through Brazil's public health system and explored factors associated with perceived treatment effectiveness.

A cross-sectional analytical study was conducted within the "Canabidiol-SUS Project." Patients registered in secondary care between 2017 and 2022 were interviewed by telephone. Effectiveness was defined as a self-reported ≥50% reduction in seizure frequency. Safety was assessed through self-reported adverse events. Logistic regression was used to identify factors associated with perceived effectiveness.

Ninety-one patients were included (mean age, 19.5 years; 58.2% male). Overall, 70.3% reported a ≥50% reduction in seizure frequency, with a higher proportion among current users (94.7%) than former users (57.1%). More than half of participants (51.6%) reported adverse events, most commonly sleep disturbances (28.6%), mood alterations (24.2%), and gastrointestinal symptoms (19.8%). Treatment duration >12 months was positively associated with perceived effectiveness (odds ratio [OR] = 23.79), whereas treatment discontinuation due to access barriers was negatively associated with effectiveness (OR = 0.074).

Patients receiving cannabis-based products frequently reported substantial seizure reduction and an acceptable safety profile in this real-world public health setting. However, interpretation should consider the cross-sectional design, self-reported outcomes, and heterogeneity of products. The association between treatment discontinuation and lower effectiveness highlights the potential impact of access barriers on treatment continuity and patient outcomes.