Bosentan may reduce the anticoagulant effects of
warfarin by 23%, and a case report describes a reduction in INR due to this interaction. However, the manufacturer of
bosentan notes that
clinical use of
bosentan with
warfarin did not result in clinically relevant changes in the INR or
warfarin dose.
It is recommended that the INR should be closely monitored in any patient taking
warfarin during the period that
bosentan is started or stopped, or if the dose is altered.