How High Can Patients Get on CBD?

Abuse potential assessment of cannabidiol (CBD) in recreational polydrug users: A randomized, double-blind, controlled trial Schoedel KA, Szeto I, Setnik B, et al. Epilepsy Behav. 2018;88:162-171. doi:10.1016/j.yebeh.2018.07.027. Epub October 2, 2018. PMID: 30286443. Rationale: Treatment with a highly purified oral solution of cannabidiol (CBD), derived from the plant Cannabis sativa L., demonstrated some evidence of central nervous system–related adverse events in patients enrolled in phase 3 trials for the treatment of childhood-onset epilepsy. Cannabidiol was categorized as a schedule 1 substance by the US Drug Enforcement Administration; therefore, it was important to test CBD for human abuse potential. Methods: This was a single-dose, randomized, double-blind, double-dummy, placebo- and active-controlled crossover trial. The abuse potential of single oral doses of plant-derived pharmaceutical formulations of highly purified CBD (Epidiolex; 750, 1500, and 4500 mg) was compared with that of single oral doses of alprazolam (2 mg), dronabinol (10 and 30 mg), and placebo in healthy recreational polydrug users. The primary end point to assess abuse potential was the maximum effect (Emax) on Drug Liking visual analog scale (VAS). Other measurements included Emax on Overall Drug Liking VAS, Take Drug Again VAS, positive and negative effects, other subjective effects, and Drug Similarity VAS. Cognitive and psychomotor functions were assessed using the Divided Attention Test, the Hopkins Verbal Learning Test–Revised, and the Digit-Symbol Substitution Task. Pharmacokinetic parameters were determined for CBD and its major metabolites. Standard safety measures and adverse events were assessed. Principal Results: Of 95 eligible patients, 43 qualified for the treatment phase, received at least 1 dose of investigational medicinal product, and were included in safety assessments; 35 patients were included in the pharmacodynamic analysis. Patients receiving alprazolam and dronabinol had significantly higher Drug Liking Emax (P <.0001) compared with those receiving placebo, confirming study validity. Compared with placebo, Drug Liking was not significantly different for patients taking 750 mg CBD (P =.51). Drug Liking Emax values for 1500 and 4500 mg CBD were significantly different from placebo (P =.04 and.002, respectively); however, the mean differences were <10 points on VAS compared with >18-point differences between positive controls and placebo. Alprazolam and dronabinol had significantly higher Drug-Liking, Overall-Liking, and Take Drug Again VAS Emax values compared with all doses of CBD (P ≤.004). In contrast to alprazolam, CBD administration had no observable effect on cognitive/psychomotor tests. Pharmacokinetic parameters for CBD in this trial were consistent with previous studies. The majority of adverse events reported during the trial were of mild or moderate severity; no serious adverse events or deaths were reported. Conclusion: Administration of a therapeutic dose of CBD (750 mg) showed significantly low abuse potential in a highly sensitive population of polydrug users. Although high and supratherapeutic doses of CBD (1500 and 4500 mg, respectively) had detectable subjective effects compared with placebo, the effects were significantly lower than those observed with alprazolam and dronabinol.