What to do with an elderly female on 3.5mg Coumadin (warfarin) daily with an elevated International Normalized Ratio (INR) of 4.4?

Management of Elevated INR (4.4) in an Elderly Female on Warfarin

For an elderly female on 3.5mg warfarin daily with an INR of 4.4, the recommended approach is to hold warfarin and administer 2.5-5mg of oral vitamin K, then recheck INR within 24 hours. 1, 2

Immediate Management

1. Hold warfarin dose immediately

   • Discontinue the current 3.5mg daily dose
   • An INR of 4.4 represents a significant elevation above the therapeutic range (2.0-3.0)

2. Administer vitamin K:

   • Give 2.5-5mg oral vitamin K (phytonadione) 1, 2
   • Oral route is preferred in non-emergency situations with this level of INR elevation
   • Note: Higher doses of vitamin K (>10mg) should be avoided as they may cause warfarin resistance for up to a week 1

3. Monitor closely:

   • Recheck INR within 24 hours after intervention 1
   • Continue daily INR checks until the therapeutic range is reached and sustained for 2 consecutive days

Clinical Assessment

Perform targeted assessment for:

• Signs of bleeding (bruising, hematuria, melena, hemoptysis)
• Recent medication changes that may interact with warfarin
• Recent dietary changes affecting vitamin K intake
• Acute illness, particularly diarrhea which can significantly elevate INR 3
• Acetaminophen use, which can dramatically increase INR even at therapeutic doses 4

Resumption of Therapy

When INR returns to therapeutic range (2.0-3.0):

• Resume warfarin at a reduced dose (10-20% reduction from previous dose) 1
• Consider 3.0-3.2mg daily instead of previous 3.5mg dose
• Continue more frequent INR monitoring initially (2-3 times weekly) until stable

Special Considerations for Elderly Patients

• Elderly patients are at higher risk for bleeding complications
• Consider a slightly lower target INR range (2.0-2.5) for elderly patients with atrial fibrillation 5
• Elderly patients may require closer monitoring during INR correction 1

Important Caveats

• Avoid fresh frozen plasma unless there is life-threatening bleeding; prothrombin complex concentrate (PCC) is preferred if severe bleeding occurs 1
• Remember that vitamin K will not provide immediate reversal - improvement in INR may take 1-8 hours 2
• If the patient has recently started antibiotics, experienced diarrhea, or changed diet, these factors may have contributed to the INR elevation 3
• The risk of bleeding increases exponentially with INR and becomes clinically unacceptable once the INR exceeds 5.0 5

Follow-up Plan

• After INR stabilizes in therapeutic range, gradually extend the interval between INR tests
• Investigate and address any underlying causes of the INR elevation
• Educate patient about diet consistency, medication interactions, and signs of bleeding
• Consider more frequent monitoring if the patient has risk factors for INR fluctuation