Safety and Efficacy of Cannabidiol for Treatment-Resistant Epilepsies

In honor of National Epilepsy Awareness Month, KannAInsight features new research on the potential benefits of cannabidiol for patients with treatment resistant epilepsy. 

In approximately 1/3 of epileptic patients, medicines fail to control seizure activity. Since 2014, patients with severe treatment-resistant epilepsies have been receiving add-on cannabidiol (CBD) through Compassionate Use Programs, which provide access to novel therapies before FDA approval. Recently, CBD (Epidiolex) was approved by the FDA for Lennox-Gastaut syndrome (LGS) and Dravet syndrome (DS). In a new study, the long-term safety and efficacy of CBD was examined in patients with treatment-resistant LGS, DS, and other epilepsies.   

Adult and pediatric patients received daily doses of CBD (Epidiolex, 2-10 mg/kg/day until maximum dose of 25-50 mg/kg/day) in addition to their prescribed medication for two years. Total seizure number was evaluated at 12-week intervals, and adverse events were assessed throughout the study and follow-up period (144 weeks total).

By 12-weeks, nearly half of all the LGS/DS patients showed ≥50% reduction in major motor and total seizures, with a consistent reduction in seizures throughout the study. Although most patients experienced adverse events (AEs), CBD had an acceptable safety profile, with the most commonly reported AEs being drowsiness, convulsion, and gastrointestinal issues. 

The results of this study support the long‐term safety and beneficial effects of CBD as an add-on treatment option for patients with treatment-resistant epilepsies. 


Laux LC, Bebin EM, Checketts D, Chez M, Flamini R, Marsh ED… CBD EAP study group. Long-term safety and efficacy of cannabidiol in children and adults with treatment resistant Lennox-Gastaut syndrome or Dravet syndrome: Expanded access program results. Epilepsy Res. 2019 Aug; 154: 13-20. 

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