Ved samtidig administration af bosentan 500 mg to gange dagligt i 6 dage faldt plasmakoncentrationen af både S- warfarin (et CYP2C9- substrat) og R- warfarin (et CYP3A4- substrat) med henholdsvis 29% og 38%.
Warfarin: co-administration of bosentan 500 mg twice daily for 6 days decreased the plasma concentrations of both S-warfarin (a CYP2C9 substrate) and R-warfarin (a CYP3A4 substrate) by 29% and 38%, respectively.