What do I do for a patient on Coumadin (warfarin) with an elevated International Normalized Ratio (INR) of 4.5 and a drop in hemoglobin (Hgb) to 10.6g/dL?

Management of INR 4.5 with Hemoglobin Drop to 10.6 on Warfarin

Stop warfarin immediately and administer 5-10 mg intravenous vitamin K by slow infusion over 30 minutes; this patient meets criteria for major bleeding requiring urgent reversal. 1, 2

Assessment of Bleeding Severity

Your patient meets the definition of major bleeding based on the American College of Cardiology criteria because she has clinically overt bleeding with a hemoglobin decrease ≥2 g/dL (assuming baseline was around 12-13 g/dL, which is typical). 1

The combination of:

• INR 4.5 (supratherapeutic)
• Hemoglobin drop to 10.6 g/dL
• Presumed ongoing bleeding source

This requires immediate action beyond simple warfarin discontinuation. 1

Immediate Management Steps

Stop warfarin and all antiplatelet agents immediately. 1

Administer 5-10 mg intravenous vitamin K by slow infusion over 30 minutes - this is the cornerstone of management for significant bleeding on warfarin. 1, 2, 3 The IV route is preferred over oral in this setting because you need more rapid reversal given active bleeding, though oral vitamin K (1-2.5 mg) would be appropriate for INR 4.5 without bleeding. 4, 5

Consider 4-factor prothrombin complex concentrate (PCC) if bleeding is life-threatening, at critical sites (intracranial, retroperitoneal, pericardial), or causing hemodynamic instability. 1, 2 PCC achieves INR <1.5 within 5-15 minutes compared to hours for vitamin K alone. 2, 3 The dose is 25-50 U/kg IV. 2

Critical Decision Point: Do You Need PCC?

You need PCC plus vitamin K if:

• Bleeding is at a critical site (see below)
• Patient is hemodynamically unstable
• Bleeding continues despite initial measures
• Emergency surgery is needed 1, 2

Critical bleeding sites include: intracranial, intraspinal, intraocular, pericardial, retroperitoneal, intra-articular, or intramuscular with compartment syndrome. 1

Vitamin K alone is sufficient if:

• Bleeding source is identified and controllable (e.g., GI bleed amenable to endoscopic intervention)
• Patient remains hemodynamically stable
• No critical site involvement 1, 2

Why Not Just Hold Warfarin?

Simply holding warfarin without vitamin K is inadequate for INR 4.5 with active bleeding. 1, 4 Warfarin has a half-life requiring 5 days to normalize INR without intervention. 1 Your patient is actively bleeding and cannot wait that long. 1

Supportive Care Measures

Provide local therapy/manual compression if bleeding source is accessible. 1

Volume resuscitation and supportive care as needed based on hemodynamic status. 1

Transfuse packed red blood cells if hemoglobin continues to drop or patient becomes symptomatic. 1

Identify and address the bleeding source - this patient needs urgent investigation (likely GI endoscopy, imaging, or other studies depending on clinical presentation) to find where she's bleeding from. 1

Important Pitfalls to Avoid

Do not use subcutaneous vitamin K - it has unpredictable and delayed absorption. 4, 5 IV or oral routes only.

Infuse IV vitamin K slowly over 30 minutes - rapid infusion causes anaphylactic reactions in 3 per 100,000 doses. 2, 3

Do not exceed 10 mg vitamin K - higher doses create a prothrombotic state and warfarin resistance lasting up to one week. 2, 3

Fresh frozen plasma (FFP) is second-line - only use if PCC is unavailable, as it requires ABO matching, has slower onset, and carries fluid overload risk. 2

Monitoring and Follow-Up

Recheck INR in 30 minutes if PCC was given, or within 4-6 hours if only vitamin K was administered. 2, 6

Target INR <1.5 for emergency procedures, but for medical management of bleeding, aim for INR 2.0-3.0 range once bleeding is controlled. 2, 6

Monitor hemoglobin every 4-6 hours until stable and bleeding source is controlled. 1

Investigate why INR became elevated - look for drug interactions, dietary changes, acute illness, or medication non-adherence. 4

When to Restart Anticoagulation

Do not restart warfarin until:

• Bleeding is completely controlled
• Source of bleeding is identified and treated
• Patient is hemodynamically stable
• You've determined the indication for anticoagulation still exists 1

Delay restart if:

• Bleeding occurred at a critical site
• Patient is at high risk of rebleeding
• Surgical procedures are planned
• Source of bleeding remains unidentified 1

Consider bridging with heparin if high-dose vitamin K (≥5 mg) was given and patient needs anticoagulation resumed, as vitamin K creates temporary warfarin resistance. 2, 3

Risk Context

The risk of bleeding increases exponentially with INR >3.0, though absolute bleeding risk remains <5.5 per 1000 per day even at INR 4-6. 5 However, your patient has already manifested bleeding, changing the risk-benefit calculation entirely. 1 Elderly patients (>65 years) have higher bleeding risk at any given INR level. 2