Clinical Studies and Case Reports

On this site you will find clinical studies with cannabis or single cannabinoids in different diseases and case reports on the use of cannabis by patients.
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TitleHigher cannabidiol plasma levels are associated with better seizure response following treatment with a pharmaceutical grade cannabidiol.
Author(s)Szaflarski JP, Hernando K, Bebin EM, Gaston TE, Grayson LE, Ampah SB, Moreadith R.
Journal, Volume, IssueEpilepsy Behav. ;95:131-136.[Epub ahead of print]
Major outcome(s)Efficacy of CBD in epilepsy is correlated to blood levels

The objective of this study was to determine the relationship between cannabidiol (CBD) dose, CBD plasma level, and seizure control in a large open-label single-center study.

All participants with treatment-refractory epilepsy participating in our expanded access program (EAP) were approached for participation. Highly purified grade CBD (Epidiolex®) dosing was weight-based and could be increased every 2 weeks by 5 mg/kg/day up to a maximum dosage of 50 mg/kg/day depending on tolerance and seizure control. Seizure counts were obtained at each visit with frequency calculated per 2-week periods. Cross-sectional plasma peak levels of CBD were obtained ~4 h after dosing in consecutively presenting patients.

We evaluated 56 adults and 44 children (100 total; 54 female) at two time points - one before initiating CBD and one at the time of CBD plasma level testing. There was a positive linear correlation between CBD dosage (range from 5 to 50&#8239;mg/kg/day) and level (range from 7.1-1200&#8239;ng/mL) in all participants (r&#8239;=&#8239;0.640; p&#8239;<&#8239;0.001). The quantile regression model supported the notion of increased CBD levels being associated with improvement in seizure frequency after adjusting for age - specifically, a 100&#8239;ng/mL increase in CBD level was associated with approximately two counts reduction in seizure frequency per time period (1.87 96% confidence interval [CI] 0.34-3.39; p&#8239;=&#8239;0.018). In participants with the same CBD level, differences in seizure improvement did not depend on age (p&#8239;=&#8239;0.318).

In this open-label study, we found evidence of a linear correlation between CBD dosage and plasma levels, and that higher dose/levels are associated with a higher response rate for seizure improvement. Children and adults responded to CBD similarly. However, seizure control response rates suggest children may respond to lower dosages/plasma levels than adults. Findings reported in this study are specific to Epidiolex® and should not be extrapolated to other CBD products.

Duration (days)
DesignOpen study
Type of publicationMedical journal
Address of author(s)
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