PGP and breast cancer: Because rivaroxaban is metabolised via cytochrome P450 (CYP) 3A4, CYP2J2 and CYP-independent mechanisms, and active renal secretion is mediated by P-gp and breast cancer resistance protein, co-administration with strong inhibitors of both CYP3A4 and P-gp, such as the azole antimycotic ketoconazole or the HIV protease inhibitor ritonavir, led to increased exposure and PD effects [3,35].