Macitentan given as multiple doses of 10 mg once daily had no effect on exposure to
S-warfarin (CYP2C9 substrate) or R-warfarin (CYP3A4 substrate) after a single dose of 25 mg
warfarin. The pharmacodynamic effect of warfarin on International Normalized Ratio (INR) was not
affected by macitentan. The pharmacokinetics of macitentan and its active metabolite were not
affected by warfarin.