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Patients with epilepsy may develop tolerance to CBD-enriched oil



Cannabis oil extract with a 20:1 ratio of cannabidiol (CBD) to tetrahydrocannabinol (THC) may reduce seizures in children and adults with treatment-resistant epilepsy, but about a quarter of patients develop tolerance, according to a study presented at the annual meeting of the American Epilepsy Society.

“CBD is a good option for children and adults with certain kinds of epilepsy, but as with antiepileptic drugs, it can become less effective over time, and the dose may need to be increased to manage the seizures,” said 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.

Prior studies have found that the efficacy of cannabinoids may wane when used for pain management. Efficacy also declines in animals with seizures.

To assess the tolerance rate of cannabinoids in the treatment of children and adults with epilepsy, researchers in Israel conducted a prospective review of 92 consecutive patients with treatment-resistant epilepsy. Patients were aged 1-37 years (mean age, 11.8 years) and were treated with cannabis oil extract during March 1, 2014–Dec. 31, 2017. The researchers defined tolerance as the need to increase the dose by at least 30% following a reduction in efficacy, or a more than 30% reduction in treatment response.

The patients had various forms of epilepsy (e.g., Dravet syndrome, Lennox-Gastaut syndrome, and epilepsy caused by stroke) and used cannabis oil extract for an average of 19.8 months. Of the 84 patients included in the tolerance analysis, 21 patients (25%) developed tolerance after an average of 7.3 months (range, 1-24 months) at an average dose of 12.6 mg/kg per day. After patients with tolerance received an increased dose, 4 patients returned to their previous response levels, and 10 patients had a response that was “satisfying but less than [the] prior response level,” Dr. Uliel-Sibony and colleagues said.

About a third of patients discontinued treatment because of side effects or lack of efficacy. Side effects included sleepiness, nausea, decreased appetite, and vomiting. In addition, seizures worsened in two patients, and one patient had signs of psychosis; treatment was stopped immediately in those three patients.

The investigators had no disclosures and received no funding for this study.

SOURCE: Uliel-Sibony S et al., AES 2018, Abstract 2.233.

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