What is the most appropriate method to rapidly lower a patient's INR who is bleeding due to warfarin?

Administering fresh frozen plasma is the most appropriate method to rapidly lower a patient's INR in the setting of bleeding due to warfarin use. Fresh frozen plasma contains clotting factors that are essential in the coagulation process, including factors II, VII, IX, and X, which are impacted by warfarin. When a patient is experiencing a significant bleed, particularly in a critical or emergent situation, the rapid infusion of fresh frozen plasma can quickly replenish these factors, effectively reversing the anticoagulation effects of warfarin and facilitating hemostasis.

While discontinuing warfarin is an important step to prevent further anticoagulation, it does not provide the immediate reversal of coagulopathy necessary in a bleeding scenario. Furthermore, administering protamine sulfate is not relevant in this case, as protamine is an antidote specifically for heparin, not warfarin. Lastly, administering heparin sulfate would further complicate the situation, as it is also an anticoagulant and would not resolve the bleeding caused by warfarin. Given the urgency of treating bleeding in patients taking warfarin, fresh frozen plasma is the most effective and rapid intervention available.