A Phase I Trial of the Pharmacokinetic Interaction Between Cannabidiol and Tacrolimus

Abstract One in six Americans uses cannabidiol‐based or cannabis‐derived products. Cannabidiol is a substrate of CYP3A, but its role as a potential CYP3A inhibitor remains unclear. We hypothesized that cannabidiol would inhibit CYP3A‐mediated metabolism of tacrolimus. This report is an interim analysis of an open‐label, three‐period, fixed‐sequence, crossover study in healthy participants. Participants first received a single dose of tacrolimus 5 mg orally. After washout, participants later received cannabidiol titrated to 5 mg/kg twice daily for 14 days to reach