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. Author manuscript; available in PMC: 2024 Sep 1.
Published in final edited form as: Clin Pharmacol Ther. 2023 Jun 30;114(3):693–703. doi: 10.1002/cpt.2973

Figure 5.

Figure 5

CYP2D6-mediated CBD-DXM interaction. (a) DXM biotransformation pathway. DXM is subsequently metabolized primarily to its glucuronide. (b) DXM plasma PK profile after administration of a brownie containing Δ9-THC (20 mg; dashed line), CBD + Δ9-THC (640 mg + 20 mg; continuous line), or placebo (dotted line). Symbols and error bars denote geometric means and 90% CIs (shown in only one direction for visual purposes), respectively (n = 16 participants; two were poor metabolizers and therefore excluded). For depiction, nominal timepoints were used. (c, d) Effects of the CBD + Δ9-THC brownie on PK end points. Horizontal bars and vertical bars denote geometric mean ratios and 90% CIs, respectively, of the parent, metabolite/parent, or metabolite CLf in the presence of the CBD + Δ9-THC brownie vs. the placebo brownie. Symbols denote values for each participant, filled symbols refer to the left Y-axis, whereas the open symbols refer to the right Y-axis. Δ9-THC, Δ9-tetrahydrocannabinol; CBD, cannabidiol; CI, confidence interval; CLf,GMR, formation clearance geometric mean ratio; DXM, dextromethorphan; fm, fraction metabolized by the indicated enzyme; PK, pharmacokinetic.