Major
Probable
Description
Methotrexate combined with warfarin increases bleeding risk and may cause enhanced anticoagulation; both drugs share protein-binding sites, amplifying free drug concentrations.
Mécanisme
Methotrexate displaces warfarin from albumin, raising free warfarin levels; warfarin may also reduce methotrexate clearance. Both drugs can impair hepatic function, affecting clotting factor synthesis.
Signification clinique
Serious bleeding events have been reported; concurrent hepatotoxicity risk adds further complexity to the interaction.
Prise en charge
Closely monitor INR and signs of bleeding; consider reducing warfarin dose empirically. Monitor liver function tests regularly.