When should INR (International Normalized Ratio) be repeated after holding Coumadin (warfarin) for 3 days due to an elevated INR of 5.96?

When to Repeat INR After Holding Warfarin for Elevated INR of 5.96

Recheck the INR within 24-48 hours after holding warfarin for 3 days to confirm appropriate reduction and guide resumption of therapy at a lower dose. 1

Immediate Management Context

For an INR of 5.96 without bleeding, the American College of Cardiology recommends omitting the next 1-2 doses of warfarin and reinstating at a lower dose when the INR falls into the therapeutic range. 2 If the patient has increased bleeding risk factors (advanced age, history of bleeding, concomitant antiplatelet drugs), oral vitamin K 1-2.5 mg should be added. 1, 3

Timing of INR Recheck

• The INR should be rechecked within 24-48 hours after the intervention (in this case, after holding warfarin for 3 days) to ensure appropriate reduction and make further dosage adjustments if needed. 1

• This 24-48 hour window allows confirmation that the INR is decreasing appropriately and ensures patient safety by preventing both bleeding and thrombotic complications. 1

• After holding warfarin for 3 days, the INR will typically have decreased substantially, as warfarin's anticoagulant effect persists beyond 24 hours but gradually diminishes. 4

What to Expect and Next Steps

• If vitamin K was administered: After oral vitamin K 1-2.5 mg, the INR typically decreases within 24 hours, with 95% of patients showing reduction and 85% achieving an INR below 4.0. 1

• When resuming warfarin: Restart at a reduced dose, approximately 10-15% lower than the previous weekly total dose. 1 The FDA label recommends flexibility in dosing, with most patients maintained on 2-10 mg daily. 4

• Subsequent monitoring: After resuming warfarin, patients who have had dose interruptions require more frequent monitoring until stability is re-established. 1 The FDA recommends intervals between subsequent INR determinations be based on the patient's reliability and response, normally within one to four weeks after a stable dosage is determined. 4

Critical Considerations

• Investigate the cause: Evaluate what led to the INR elevation—consider drug interactions, dietary changes (particularly vitamin K intake), compliance issues, or intercurrent illness. 1

• Bleeding risk assessment: Even at INR 5.96, the absolute daily risk of bleeding remains relatively low, but risk increases exponentially as INR rises above 5.0. 1 Elderly patients (>65 years) have higher bleeding risk at any given INR level. 1, 3

• Avoid common pitfalls: Do not administer high-dose vitamin K unnecessarily, as this can lead to warfarin resistance and difficulty re-establishing therapeutic anticoagulation. 1 For INR 5-9 without bleeding, low-dose vitamin K (1-2.5 mg) is sufficient if needed at all. 1, 3

Algorithm Summary

1. Day 0: Hold warfarin for INR 5.96 (already done for 3 days in this scenario)
2. Day 3-4: Recheck INR within 24-48 hours 1
3. If INR therapeutic: Resume warfarin at 10-15% lower weekly dose 1
4. If INR still elevated: Continue holding and recheck in another 24-48 hours
5. After resumption: Monitor INR 2-3 times weekly for 1-2 weeks until stable 3