CYP3A4 and cancer: Direct oral anticoagulants (DOACs) are becoming the preferred anticoagulant for patients with cancer for the prevention and treatment of thromboembolism.7,8,9 Direct oral anticoagulants are substrates of 2 main metabolic pathways: P-glycoprotein (P-gp) cell transporters and cytochrome P450 enzyme (CYP3A4) in the liver.10 Edoxaban and dabigatran are involved in the P-gp pathway, whereas apixaban and rivaroxaban are involved in both.