Abstract Cannabidiol (CBD) has been shown to inhibit mouse hepatic mixed-function oxidations of several drugs after acute treatment, whereas repetitive treatment resulted in the restoration of drug-metabolizing capabilities. We have found that acute CBD treatment modestly decreased cytochrome P-450 content but markedly decreased hexobarbital hydroxylase, erythromycin N-demethylase, and 6 beta-testosterone hydroxylase activities. Repetitive CBD treatment, on the other hand, resulted in the restoration of cytochrome P-450 content as well as hexobarbital hydroxylase and erythromycin N-demethylase activities. However, after such repeated treatments a fresh dose of CBD can once again inactivate erythromycin N-demethylase activity but not hexobarbital hydroxylase activity. The resistance of hexobarbital hydroxylase to...

This Phase I study aimed to assess the potential drug-drug interactions (pharmacokinetic [PK] and safety profile) of Δ9-tetrahydrocannabinol (THC)/cannabidiol (CBD) oromucosal spray (Sativex®, nabiximols) in combination with cytochrome P450 (CYP450) inducer (rifampicin) or inhibitors (ketoconazole or omeprazole). Thirty-six healthy male subjects were divided into three groups of 12, and then randomized to one of two treatment sequences per group. Subjects received four sprays of THC/CBD (10.8/10 mg) alongside single doses of the CYP3A and 2C19 inducer rifampicin (600 mg), CYP3A inhibitor ketoconazole (400 mg) or CYP2C19 inhibitor omeprazole (40 mg). Plasma samples were analyzed for CBD, THC and its metabolite 11-hydroxy-THC (11-OH-THC). A single...

Aims: Cannabidiol (CBD), one of the major constituents in marijuana, has been shown to be extensively metabolized by experimental animals and humans. However, human hepatic enzymes responsible for the CBD metabolism remain to be elucidated. In this study, we examined in vitro metabolism of CBD with human liver microsomes (HLMs) to clarify cytochrome P450 (CYP) isoforms involved in the CBD oxidations. Main methods: Oxidations of CBD in HLMs and recombinant human CYP enzymes were analyzed by gas chromatography/mass spectrometry. Key findings: CBD was metabolized by pooled HLMs to eight monohydroxylated metabolites (6α-OH-, 6β-OH-, 7-OH-, 1″-OH-, 2″-OH-, 3″-OH-, 4″-OH-, and 5″-OH-CBDs). Among these metabolites, 6α-OH-,...

Effects of four cannabinoids [cannabidiol (CBD), delta 8-tetrahydrocannabinol, delta 9-tetrahydrocannabinol, and cannabinol] on hepatic microsomal oxidation of testosterone (17 beta-hydroxy-androst-4-ene-3-one) were examined in adult male rats. Only CBD (30 microM) competitively inhibited 2 alpha-hydroxy-testosterone (2 alpha-OH-T) and 16 alpha-OH-T formation by hepatic microsomes but did not affect androstenedione (androst-4-ene-3,17-dione) and 7 alpha-OH-T formation. Kinetic analyses demonstrated that the inhibitory profile of CBD for testosterone oxidation was different from those of SKF 525-A, which caused competitive inhibition for 2 alpha- and 16 alpha-hydroxylations and noncompetitive inhibition for 6 alpha-hydroxylation, and of metyrapone, which inhibited only 6 beta-hydroxylation competitively. CBD also suppressed formation of 2 alpha-OH-T,...