. 2022 Jun;17(6):911–921. doi: 10.2215/CJN.11560821

Table 3.

Important potential or reported drug interactions with tetrahydrocannabinol and cannabidiol

Drugs Affected by Tetrahydrocannabinol and Cannabidiol				Drugs Affecting Tetrahydrocannabinol and Cannabidiol Exposure
THC interacts with warfarin via an unknown mechanism	CBD inhibits CYP 2D6, 2B6, and 2C19, and UGT 1A9 and 2B7			Both THC and CBD are metabolized by CYP 3A4. CBD is also metabolized by 2C19
THC increases levels of:	CBD increases levels of:		CBD reduces levels of:	Increased levels of THC/CBD	Reduced levels of THC/CBD
Mechanism unclear Warfarin	2D6 substrates Amitriptyline Nortriptyline Desipramine Flecainide Haloperidol Risperidone 2C19 substrates Citalopram Diazepam Escitalopram Tacrolimus Voriconazole Warfarin Omeprazole	2B6 substrates Methadone UGT1A9 and UGT2B7 substrates Mycophenolate Dabigatran Mechanism unclear Everolimus Sirolimus	Dependent on 2D6 for activation Codeine Tamoxifen Tramadol Partly dependent on 2C19 for activation Clopidogrel	Strong 3A4 inhibitors Clarithromycin Itraconazole Ketoconazole Posaconazole Ritonavir Voriconazole Moderate 3A4 inhibitors Amiodarone Cyclosporine Diltiazem Erythromycin Fluconazole Grapefruit juice Imatinib Verapamil	Strong 3A4 inducers Carbamazepine Phenytoin Rifampin (rifampicin)^a Moderate 3A4 inducers Bosentan Dabrafenib Dexamethasone Rifabutin St. John's wort 2C19 inducers^b Apalutamide

References (106,27,107): Listed enzymes are cytochrome P450 (CYP) unless otherwise indicated. THC, tetrahydrocannabinol; CBD, cannabidiol; UGT, uridine 5′-diphospho-glucuronosyltransferase.

Also an inducer of 2C19.

CBD only.