Management of INR 6.0 on Warfarin
For a patient with INR 6.0 without active bleeding, warfarin should be held completely until the INR falls back into the therapeutic range, which typically occurs within 24-72 hours in most patients. 1, 2
Duration of Warfarin Hold
Approximately 33% of patients with INR >6.0 will have INR <4.0 within 24 hours, 55% within 48 hours, 73% within 72 hours, and nearly 90% within 96 hours after temporarily discontinuing warfarin therapy. 3
The INR should be rechecked within 24-48 hours after holding warfarin to confirm appropriate reduction, and monitoring should continue every 24-48 hours until the INR stabilizes in the therapeutic range. 2, 4
Warfarin can be restarted once the INR falls below 3.5, but at a reduced weekly dose of 20-30% to prevent recurrence of supratherapeutic INR. 2, 4
Vitamin K Considerations
For INR 6.0 without bleeding, vitamin K is NOT routinely recommended unless the patient has increased bleeding risk factors such as advanced age (>65-75 years), history of bleeding, concomitant antiplatelet drugs, renal failure, or alcohol use. 1, 2
If vitamin K is indicated due to high bleeding risk, administer oral vitamin K 1-2.5 mg, which achieves INR <4.0 within 24 hours in 85% of patients. 2, 4
Randomized trials show that routine vitamin K use for INR 4.5-10 without bleeding does not reduce major bleeding despite faster INR normalization, supporting a conservative approach. 2
Bleeding Risk Assessment
Patients with INR >6.0 face a significant short-term risk of major hemorrhage: 8.8% seek medical attention for abnormal bleeding and 4.4% experience major hemorrhage during 14-day follow-up. 3
The bleeding risk becomes clinically significant primarily when INR exceeds 5.0, with elderly patients having higher bleeding risk at any given INR level. 2, 5
Critical Pitfalls to Avoid
Do NOT administer high-dose vitamin K (≥10 mg) for non-bleeding situations, as this creates warfarin resistance for up to a week and makes re-anticoagulation extremely difficult. 2, 4
Do NOT use IV vitamin K unless there is active bleeding, due to the risk of anaphylactoid reactions (3 per 100,000 doses) that can result in cardiac arrest. 2, 4
Do NOT restart warfarin at the original dose without reduction—reduce the weekly dose by 20-30% to prevent recurrence. 2, 4
When to Escalate Management
If active bleeding develops at any point during monitoring, immediately administer 4-factor prothrombin complex concentrate (PCC) 50 U/kg IV plus vitamin K 5-10 mg by slow IV infusion over 30 minutes for rapid reversal. 2
Investigation Required
Before restarting warfarin, identify and address the cause of INR elevation, including new medications, dietary changes (vitamin K intake), compliance issues, acute illness, or changes in liver/renal function. 2, 4