Safety of Co-Administered Cannabidiol (CBD) and alcohol: a Phase I study

Background This Phase I randomized controlled trial aimed to assess the safety and tolerability of cannabidiol (CBD) and alcohol co-administration among moderate alcohol consumers in acute laboratory and chronic outpatient settings. Methods Healthy adults ages 21–65 with moderate alcohol use completed three acute dosing sessions where they received either placebo, 50 mg CBD, or 100 mg CBD along with alcohol dosed to achieve peak blood alcohol concentrations (BAC) of 0.06 g/100 mL. Sessions were randomly ordered, and participants and outcome assessors were blinded to study drug during these laboratory sessions. Breath alcohol content (BrAC) and measures of subjective effects and impairment were collected from participants throughout each session. Participants then consumed 50 mg CBD twice daily for four weeks as outpatients while reporting alcohol use, craving, and adverse effects via a smartphone app. Metabolic labs and CBD content were measured from blood samples collected at four-week follow-up. Results Twenty-nine participants were enrolled and nineteen participants completed the study. CBD was well-tolerated in both acute and chronic dosing sessions. Acute CBD-alcohol use was not associated with significant differences in subjective responses or breath alcohol content (BrAC) peak or time course compared to placebo for either CBD condition. Acute CBD-alcohol use was not associated with impairment 4 h after dosing. CBD use was not associated with significant changes in alcohol cravings or drinks per day, nor significant lab changes outside of decreases in protein and globulin, across the chronic dosing period. Conclusions CBD co-administration with alcohol was not associated with significant changes in subjective or physiologic effects among moderate alcohol consumers in acute laboratory and naturalistic outpatient settings. The safety of CBD use in patients with more severe alcohol use should be examined in future studies. Trial registration This study was registered at ClinicalTrials.gov on April 7th, 2022 under the code NCT05317507.