A nurse is caring for a client who is prescribed warfarin. Which of the following actions should the nurse take?

A. Increasing dietary intake of vitamin K would decrease the effectiveness of warfarin, as vitamin K is involved in clotting factor synthesis. B. St. John's wort decreases the effects of warfarin, so it should be avoided. C. Protamine sulfate is the antidote for heparin, not warfarin. The antidote for warfarin overdose is vitamin K. D. Monitoring prothrombin time (PT) and INR is essential to assess the effectiveness and safety of warfarin therapy.