Question

A patient who is taking warfarin [Coumadin] has just vomited blood. The nurse notifies the provider, who orders lab work revealing a PT of 42 seconds and an INR of 3.5. The nurse will expect to administer:

a. phytonadione (vitamin K1) 1 mg IV over 1 hour.
b. phytonadione (vitamin K1) 2.5 mg PO.
c. protamine sulfate 20 mg PO.
d. protamine sulfate 20 mg slow IV push.

Answer 1

In a case of warfarin overdose indicated by severe bleeding and elevated INR, the correct treatment is the administration of phytonadione (vitamin K1), specifically 1 mg IV over 1 hour to reverse the effects of the anticoagulant and restore clotting function.

Step-by-step explanation:

The patient described is experiencing severe bleeding and has a significantly elevated International Normalized Ratio (INR) of 3.5 likely due to warfarin therapy, a medication used to prevent clotting. Warfarin works by antagonizing the effects of Vitamin K, which is necessary for the synthesis of clotting factors produced by the liver. When the Prothrombin Time (PT) is prolonged, and the INR is high, the blood's ability to clot is reduced, leading to risks such as bleeding and hemorrhage. Vitamin K is used to reverse the effects of warfarin because it helps in the production of clotting factors and thus normalizes clotting time. Therefore, the nurse will expect to administer phytonadione (vitamin K1) 1 mg IV over 1 hour to counteract the warfarin overdose and reduce the risk of bleeding.

It should be noted that protamine sulfate is an antidote for heparin, not warfarin, and would not be the correct treatment in this context. The use of IV phytonadione is indicated for rapid reversal of the effects of warfarin when there is significant bleeding. Additionally, pharmacogenomics can assist patients on warfarin therapy by identifying individual genetic variations that influence drug metabolism and responsiveness, potentially optimizing dosing and reducing the risk of overdose or adverse effects.