Efficacy of Cannabidiol for controlling epileptic seizures declines over time

Israel: Cannabidiol (CBD), a marijuana-derived drug that helps in the management of epileptic seizures, appears to become less effective over time in some patients, report researchers from Israel.

The study, presented at the American Epilepsy Society annual meeting, suggest that CBD tolerance exists and it limits the efficacy of this antiseizure treatment in the long-term clinical management of epilepsy in the pediatric and adults population.

This prospective study involved 92 children and young adults with treatment-resistant seizures who used cannabis oil extract for an average of 29.8 months. Tolerance was defined as either the necessity to increase dose in 30% or more following reduction of efficacy or response reduction of more than 30%.

Key Findings:

• Tolerance was seen in 30 (32.6%) of the patients. It was reported on an average dose of 12.6 mg/kg/d and the meantime until the appearance of tolerance was 7.3 months (range: 1-24 months).


• Out of these patients, 58% (17 patients) showed > 50% reduction in mean monthly seizure frequency.


• While trying to resist the tolerance effect, CBD dose was increased in most patients with observed tolerance. This led to achieving previous response level in 12 and satisfying but less than prior response level in 15 patients.


• Of the patients with observed tolerance, in nine it was concomitant with drug's tapering.

"CBD is a good option for children and adults with certain kinds of epilepsy, but as with anti-epileptic drugs, it can become less effective over time and the dose may need to be increased to manage the seizures," Uliel-Sibony, Shimrit Uliel-Sibony, MD, lead author of the study and head of the pediatric epilepsy service at Tel Aviv Sourasky Medical Center's Dana-Dwek Children's Hospital, Israel, said in a statement.

While previous research has shown that the effectiveness of cannabinoids can decrease when it is used for pain management and in the treatment of animals with seizures, this is the first large study to show it can occur with humans who use CBD to treat epilepsy, she added.

In the U.S., the FDA has approved a purified, pharmaceutical-grade formulation of cannabidiol (Epidiolex), a chemical component of the Cannabis sativa plant, for children with Lennox-Gastaut and Dravet syndromes.

There was no statistically significant correlation between patient's age and tolerance, but patients with shorter epilepsy duration showed a higher tendency to develop tolerance, noted the researchers. Predictive factors and mechanisms are unknown, and long-term studies to better characterize the long-term efficacy and safety of CBD are needed, they added.

For further reference follow the link: https://www.aesnet.org/meetings_events/annual_meeting_abstracts/view/501344