A patient on warfarin has an INR of 6. Which medication should be administered?

When a patient on warfarin presents with an INR of 6, this indicates a significantly elevated risk of bleeding since the therapeutic range for INR in most conditions is typically between 2.0 and 3.0. An INR of 6 means that the anticoagulant effect is too strong, requiring immediate reversal to prevent potential bleeding complications.

Administering Vitamin K directly counteracts the effects of warfarin by providing a source of vitamin K, which is essential for the synthesis of clotting factors that warfarin inhibits. This action helps to normalize the INR and reduce the risk of bleeding. In cases of severe INR elevation, Vitamin K can be given orally or intravenously, depending on the clinical scenario and urgency.

Other medications listed do not serve the purpose of reversing the effects of warfarin. For instance, furosemide is a diuretic and does not impact clotting times. Heparin, while an anticoagulant like warfarin, would further increase bleeding risk rather than help in reversing the effects of warfarin. Aspirin, also an antiplatelet agent, does not affect INR directly and could exacerbate the risk of bleeding. Therefore, Vitamin K is the safest and most effective