Interação entre Fitomenadiona (vitamina K1) e Varfarina

Polycythemia vera Vasculitis Diabetes mellitus 5.9 Endogenous Factors Affecting INR The following factors may be responsible for increased INR response: diarrhea, hepatic disorders, poor nutritional state, steatorrhea, or vitamin K deficiency.

The following factors may be responsible for decreased INR response: increased vitamin K intake or hereditary warfarin resistance.

Pharmacodynamic mechanisms for drug interactions with warfarin sodium are synergism (impaired hemostasis, reduced clotting factor synthesis), competitive antagonism (vitamin K), and alteration of the physiologic control loop for vitamin K metabolism (hereditary resistance).

The amount of vitamin K in food may affect therapy with warfarin sodium.

Advise patients taking warfarin sodium to eat a normal, balanced diet maintaining a consistent amount of vitamin K.

Anticoagulants Phytonadione injectable emulsion may induce temporary resistance to prothrombin-depressing anticoagulants, especially when larger doses of phytonadione injectable emulsion are used.

Should this occur, higher doses of anticoagulant therapy may be needed when resuming anticoagulant therapy, or a change in therapy to a different class of anticoagulant may be necessary (i.e., heparin sodium).

Anticoagulants: May induce temporary resistance to prothrombin-depressing anticoagulants.

Phytonadione injectable emulsion does not affect the anticoagulant action of heparin.