What is the recommended course of action for a patient with an INR of 1.5 who started Eliquis (apixaban) 5mg twice daily 6 days ago?

Management of Patient with INR 1.5 on Apixaban

For a patient with an INR of 1.5 who started Eliquis (apixaban) 5mg twice daily 6 days ago, no intervention is needed as the elevated INR is an expected finding with apixaban therapy and does not require dose adjustment or discontinuation.

Understanding INR and Apixaban

Apixaban is a direct factor Xa inhibitor that does not require INR monitoring for dose adjustment. Unlike warfarin, which targets INR values between 2.0-3.0, apixaban has predictable pharmacokinetics and does not require routine laboratory monitoring 1.

Key points regarding INR and apixaban:

• INR is not a valid measure of anticoagulation effect for direct oral anticoagulants (DOACs) like apixaban
• Apixaban can cause mild elevations in INR (typically 1.4-1.7) even at therapeutic doses 2
• An INR of 1.5 is within the expected range for patients on apixaban therapy

Clinical Approach

Assessment

1. Verify the apixaban dosing is appropriate:

   • Standard dosing: 5mg twice daily
   • Reduced dosing (2.5mg twice daily) for patients with at least two of:
     • Age ≥80 years
     • Body weight ≤60 kg
     • Serum creatinine ≥1.5 mg/dL 3, 4

2. Check for signs of bleeding:

   • No intervention needed if no bleeding is present
   • If bleeding occurs, consider temporary discontinuation based on severity

3. Evaluate renal function:

   • Apixaban is 27% renally excreted 4
   • Dose adjustment not typically needed for mild to moderate renal impairment

Management Decision

For a patient with INR 1.5 on apixaban without bleeding:

• Continue current apixaban dosing
• Do not adjust dose based on INR value
• Do not add vitamin K or other reversal agents

Special Considerations

Switching Between Anticoagulants

If the patient was recently switched from warfarin to apixaban:

• The elevated INR may reflect residual warfarin effect
• Apixaban should only be started when INR is below 2.0 3
• Continue apixaban as prescribed

Perioperative Management

If surgery is planned:

• For low bleeding risk procedures: discontinue apixaban 1 day before surgery
• For high bleeding risk procedures: discontinue apixaban 2 days before surgery 4
• No bridging anticoagulation is required

Drug Interactions

Check for medications that may interact with apixaban:

• Combined P-glycoprotein and strong CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir) require 50% dose reduction 3
• Avoid concomitant use with drugs that increase bleeding risk (NSAIDs, antiplatelet agents) 1

Common Pitfalls to Avoid

1. Do not adjust apixaban dose based on INR values

   • INR is designed for monitoring warfarin, not DOACs

2. Do not order routine INR monitoring for patients on apixaban

   • This creates unnecessary concern and potential for inappropriate interventions

3. Do not administer vitamin K to "correct" the INR

   • Vitamin K antagonizes warfarin but has no effect on apixaban

4. Do not discontinue apixaban solely due to elevated INR

   • Discontinuation increases thrombotic risk without clinical benefit

Conclusion

An INR of 1.5 in a patient taking apixaban 5mg twice daily for 6 days is an expected finding that does not require intervention. Continue the prescribed apixaban regimen and reassure the patient that INR monitoring is not necessary for this medication.