Increased exposure & risk of dyspnea, bleeding, other adverse events w/ strong CYP3A inhibitors (eg, ketoconazole, itraconazole, voriconazole, clarithromycin, nefazodone, ritonavir, saquinavir, nelfinavir, indinavir, atazanavir, & telithromycin). Reduced exposure & efficacy w/ strong CYP3A inducer (eg, rifampin, phenytoin, carbamazepine & phenobarb). Reduced effectiveness in concomitant use w/ aspirin w/ maintenance doses >100 mg. Delayed & reduced absorption w/ opioid agonists. Inhibited P-gp transporter; monitor digoxin levels.