Abstract
Introduction: Despite US FDA approval of cannabidiol (CBD) liquid (Epidiolex®), patients with epilepsy still supplement prescription treatments with dispensary CBD. This study aimed to evaluate therapeutic effectiveness of dispensary CBD. Methods: We retrospectively collected dosage information, CBD serum levels, efficacy, and adverse effects from patient charts (children, adolescents, adults) (n = 18). Results: All 18 patients showed no clinical benefit from dispensary CBD as detectable serum levels never reached a therapeutic range of 150 ng/mL (6 patients had barely detectable levels that were below laboratory reporting thresholds). Minute levels of tetrahydrocannabinol (THC) were found in 3 patients, and moderate levels were found in 1 patient. Conclusion: Dispensary CBD failed to reach effective therapeutic levels in all of these patients. The presence of THC demonstrates the current lack of regulation of dispensary CBD. Anecdotal reports of clinical effectiveness should be considered an effect of concomitant prescription antiseizure medications and not dispensary CBD.