NCLEX-RNPharmacological and Parenteral TherapiesMedium
A client taking warfarin for atrial fibrillation has an INR of 5.5 and reports no bleeding. The target INR range for this client is 2-3. Which action should the nurse anticipate?
- AIncrease the warfarin dose to reach the target range faster
- BAdminister the next scheduled warfarin dose as ordered
- CAdminister protamine sulfate immediately
- DHold warfarin and prepare to administer vitamin K as ordered
Show answer & explanationAnswer & explanation
Correct answer: D. Hold warfarin and prepare to administer vitamin K as ordered
An INR of 5.5 is significantly above the therapeutic range of 2-3 and places the client at high risk for spontaneous bleeding. The nurse should anticipate holding the warfarin dose and administering vitamin K (phytonadione), the antidote for warfarin, as ordered.
Why the other options are wrong
- A. Increasing the dose would dangerously worsen the supratherapeutic INR.
- B. Giving another dose would further raise the INR and bleeding risk.
- C. Protamine sulfate reverses heparin, not warfarin.
Warfarin & INR Monitoring
Warfarin therapy is monitored using INR, with a typical therapeutic target of 2-3 for most indications; vitamin K is the antidote for excessive anticoagulation.
- Therapeutic INR for AFib/DVT is usually 2-3
- Vitamin K (phytonadione) reverses warfarin effect
- INR >5 without bleeding often managed by holding dose ± oral vitamin K
Memory trick: 'Vitamin K Kicks warfarin back down'