Increased exposure w/ systemic ketoconazole, clarithromycin, ritonavir, telaprevir, indinavir, lopinavir, idelalisib, conivaptan, cobicistat, darunavir, itraconazole, atazanavir. Reduced plasma conc w/ rifampin, nevirapine, primidone, carbamazepine, phenytoin, St. John's wort. Increased risk of bleeding w/ warfarin, enoxaparin, fondaparinux, acenocoumarol, dalteparin, phenprocoumon, dabigatran etexilate, argatroban, SNRIs & SSRIs, lepirudin, heparin, tinzaparin, bivalirudin, protein C, desirudin, danaparoid, drotrecogin α, phenindione, idelalisib, conivaptan. Decreased efficacy & possible subtherapeutic anticoagulation w/ oxcarbazepine.