What does an International Normalized Ratio (INR) of 1.14 indicate for a patient on warfarin (Coumadin) therapy?

Management of INR 1.14 on Warfarin Therapy

An INR of 1.14 indicates subtherapeutic anticoagulation that requires immediate dose adjustment—increase the weekly warfarin dose by 5-20% and recheck the INR within 3-7 days. 1

What This INR Value Means

• An INR of 1.14 is significantly below the therapeutic range of 2.0-3.0 required for most indications including atrial fibrillation, venous thromboembolism, and bileaflet mechanical aortic valves. 2, 3

• This subtherapeutic level provides inadequate protection against thromboembolism and places the patient at increased risk for stroke, DVT, or PE depending on their underlying condition. 2

• A baseline INR for patients not on warfarin is 1.0, so an INR of 1.14 indicates minimal anticoagulant effect. 2

Immediate Management Steps

Dose Adjustment:

• Increase the total weekly warfarin dose by 5-20% based on how far below target the INR is. 1
• For an INR this low (1.14 versus target 2.0-3.0), consider a 15-20% increase in the weekly dose. 4
• Do not administer vitamin K—vitamin K is only indicated for elevated INR values with or without bleeding, not for subtherapeutic levels. 1

Recheck Timing:

• Recheck the INR within 3-7 days after dose adjustment. 1
• More frequent monitoring (2-4 times per week) is appropriate until the therapeutic range is achieved and sustained for 2 consecutive days. 2

Identify Contributing Factors

Medication and Dietary Assessment:

• Screen for new medications that may induce warfarin metabolism, including over-the-counter drugs, antibiotics, NSAIDs, and herbal supplements. 1
• Assess for increased dietary vitamin K intake, which antagonizes warfarin's effect—common sources include leafy green vegetables, broccoli, and certain oils. 1, 2
• Verify medication adherence, as missed doses are a common cause of subtherapeutic INR. 1

Clinical Factors:

• Evaluate for diarrhea or decreased oral intake, which can affect vitamin K absorption and warfarin levels. 5
• Consider weight changes, as these may alter warfarin requirements. 2

Risk Stratification for Bridging

Most patients do NOT require bridging anticoagulation with low molecular weight heparin (LMWH) for a single subtherapeutic INR. 1

Consider bridging ONLY in very high-risk patients:

• Mechanical mitral valve (especially older valve types like caged ball or caged disk). 1, 3
• Recent thromboembolism within the past 3 months. 1
• History of thromboembolism while previously anticoagulated. 1
• Multiple prior thromboembolic events. 3

Follow-Up Monitoring

• Once the INR reaches therapeutic range (2.0-3.0) and is sustained for 2 consecutive days, reduce monitoring frequency to 2-3 times weekly for 1-2 weeks. 2
• After stability is demonstrated, monitoring can be reduced to weekly for 1 month, then eventually to intervals as long as 4 weeks. 2
• Resume more frequent monitoring if there are changes in diet, weight, medications, illness, or any signs of bleeding or thrombosis. 2

Common Pitfalls to Avoid

• Do not give loading doses or make excessive dose increases—adjust the weekly dose by 5-20% increments to avoid overshooting into supratherapeutic range. 1, 4
• Do not delay dose adjustment—subtherapeutic anticoagulation significantly increases thromboembolic risk and requires prompt correction. 2
• Do not routinely bridge with LMWH—this is only necessary in very high-risk patients and adds bleeding risk. 1
• Do not target lower INR ranges (e.g., 1.5-2.0)—these lack objective validation and provide inadequate protection against thromboembolism. 2