👤 By the CinnaRN Clinical Content Team🕐 Updated 2026-08-23🏷️ Pharmacological Therapies🔖 Free to read, print, and share
Also known as: warfarin · coumadin · oral anticoagulant
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Use this quick-reference guide to spot, treat, and prevent Warfarin Therapy on the NCLEX. Keep it handy during review and on exam day!
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📒 The 1-minute cheat sheet
🧪 Labs
Monitor PT / INR
Therapeutic INR 2–3
INR > 4 → bleeding risk, hold
🧪 Meds
Vitamin K = antidote
Slow onset → overlap heparin
🎓 Teach
Consistent vit K (greens) intake
No NSAIDs, ASA, herbal
Soft toothbrush, e-razor
🚩 Report
Bruising, dark stools, bleeding
Teratogenic → no pregnancy
📚 Warfarin Therapy — full study notes
The cheat sheet above is your quick recall card. These notes go deeper — what it is, what to do first, what must be reported, and what to teach.
Warfarin is an oral anticoagulant that blocks vitamin K–dependent clotting factors. It has a slow onset (days), is monitored with PT/INR, and its antidote is vitamin K. It is used for long-term clot prevention (e.g., atrial fibrillation, DVT, mechanical valves).
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Key points
Understand these first
Monitor PT/INR — therapeutic INR is usually 2–3 (2.5–3.5 for mechanical valves)
Antidote: vitamin K (phytonadione)
Onset is slow, so heparin often 'bridges' until warfarin is therapeutic
Many drug/food interactions — green leafy vegetables (vitamin K) reduce its effect
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Nursing priorities
What to do, in order
Check INR regularly and assess for bleeding
Keep vitamin K available as the reversal agent
Teach a consistent (not necessarily low) vitamin K intake — avoid big swings
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Red flags — report now
Escalate immediately
INR > 4–5 or active bleeding — hold the dose and notify the provider
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Labs & values
Numbers to know
INR therapeutic 2–3 (mechanical valve 2.5–3.5)
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Patient teaching
What patients must know
Keep leafy-green intake steady; avoid alcohol; tell every provider you take warfarin
Use a soft toothbrush and electric razor; report unusual bleeding
❓ Warfarin Therapy: NCLEX FAQs
What are the priority nursing interventions for Warfarin Therapy?
Check INR regularly and assess for bleeding. Keep vitamin K available as the reversal agent. Teach a consistent (not necessarily low) vitamin K intake — avoid big swings.
What are the warning signs of Warfarin Therapy a nurse must report?
INR > 4–5 or active bleeding — hold the dose and notify the provider.
What do I need to know about Warfarin Therapy for the NCLEX?
Monitor PT/INR — therapeutic INR is usually 2–3 (2.5–3.5 for mechanical valves). Antidote: vitamin K (phytonadione). Onset is slow, so heparin often 'bridges' until warfarin is therapeutic. Many drug/food interactions — green leafy vegetables (vitamin K) reduce its effect.
What patient teaching is important for Warfarin Therapy?
Keep leafy-green intake steady; avoid alcohol; tell every provider you take warfarin. Use a soft toothbrush and electric razor; report unusual bleeding.
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Quick Tip
Monitor PT/INR — therapeutic INR is usually 2–3 (2.5–3.5 for mechanical valves).