What is the treatment for a patient with a raised International Normalized Ratio (INR)?

Management of Raised INR

The treatment for a raised International Normalized Ratio (INR) depends on the INR level, presence of bleeding, and individual patient risk factors, with strategies ranging from withholding warfarin for mildly elevated INRs to administering prothrombin complex concentrate (PCC) and vitamin K for severe elevations with bleeding.

Treatment Algorithm Based on INR Level

INR 3.0-5.0 (Mildly Elevated)

• Omit next warfarin dose or reduce subsequent doses 1
• Resume warfarin when INR returns to therapeutic range
• No vitamin K administration required
• Monitor INR within 24-48 hours

INR 5.0-9.0 (Moderately Elevated) Without Bleeding

• Temporarily suspend warfarin therapy 1
• For patients with high bleeding risk: administer oral vitamin K1 (1.0-2.5 mg) 2, 1
• Monitor INR daily until stable
• Resume warfarin at lower dose when INR approaches therapeutic range

INR >9.0 (Severely Elevated) Without Bleeding

• Suspend warfarin therapy 1
• Administer oral vitamin K1 (2.5-5.0 mg) 2, 1
• Monitor INR every 24 hours
• Consider additional vitamin K1 dose (1.0-2.0 mg) if INR remains elevated after 24 hours 1

Any INR with Active Bleeding

• For non-life-threatening bleeding:

  • Withhold warfarin
  • Administer vitamin K1 (1-5 mg orally or slow IV infusion) 2, 1
  • Consider fresh frozen plasma (FFP) if more rapid reversal needed

• For life-threatening or intracranial bleeding:

  • Administer 4-factor prothrombin complex concentrate (PCC) at 25-50 units/kg based on INR and weight 1
  • Give vitamin K1 (5-10 mg) by slow IV infusion over 30 minutes 2
  • PCC is preferred over FFP due to faster onset, lower volume requirements, and fewer transfusion reactions 1

Route of Vitamin K Administration

• Oral administration is preferred for non-urgent INR reversal due to:

  • Predictable effectiveness
  • Convenience and safety compared to parenteral routes 2
  • Lower risk of anaphylactic reactions than IV administration

• Intravenous administration should be reserved for cases requiring very rapid reversal:

  • Must be given by slow infusion (over 30 minutes)
  • Carries risk of anaphylactic reactions 2

• Subcutaneous administration is not recommended due to unpredictable and sometimes delayed response 2

Special Considerations

Patients with Mechanical Heart Valves

• Avoid rapid reversal unless life-threatening bleeding is present 1
• Consult with anticoagulation management team before reversal 1
• Consider lower doses of vitamin K to prevent prolonged warfarin resistance

Monitoring After Treatment

• For patients given vitamin K, check INR within 24 hours 2, 1
• For patients with withheld warfarin only, recheck INR in 1-2 days 3
• Continue daily INR monitoring until stable and within therapeutic range

Important Caveats

• High doses of vitamin K1 (>10 mg) may cause warfarin resistance for up to a week 2
• Oral vitamin K1 in low doses (1-2.5 mg) effectively reduces INR without causing significant warfarin resistance 2
• After warfarin is interrupted without vitamin K, the INR falls over several days (an INR between 2.0-3.0 falls to normal range in 4-5 days) 2
• When restarting warfarin after reversal, consider lower maintenance doses, especially for elderly or debilitated patients 4

The evidence clearly shows that treatment approach should be tailored to the severity of INR elevation and presence of bleeding, with oral vitamin K being the preferred treatment for most non-emergency situations with significantly elevated INR.