What dose of Coumadin (warfarin) should be given to a patient with an International Normalized Ratio (INR) of 2.7, who has been withheld from Coumadin, with an INR goal of 2 to 3 for atrial fibrillation (AF)?

Warfarin Management for INR 2.7 in Atrial Fibrillation

Resume your usual maintenance dose of warfarin immediately, as an INR of 2.7 is within the therapeutic target range of 2.0-3.0 for atrial fibrillation. 1, 2

Current INR Assessment

• Your patient's INR of 2.7 falls within the optimal therapeutic range of 2.0-3.0 recommended for stroke prevention in atrial fibrillation 1
• The target INR to aim for within this range is 2.5, which maximizes stroke protection while minimizing bleeding risk 1, 3
• An INR of 2.7 provides maximum protection against ischemic stroke without significantly increasing hemorrhagic risk 1

Immediate Management

Resume the patient's previous maintenance dose of warfarin today. 2

• Since warfarin was being withheld and the INR has now fallen into the therapeutic range, there is no need for dose reduction or continued withholding 2
• The FDA label states that most patients are satisfactorily maintained at doses of 2-10 mg daily, with dosing adjusted to maintain INR 2.0-3.0 for atrial fibrillation 2
• If the previous maintenance dose is unknown, initiate warfarin at 2-5 mg daily, with lower doses (2-3 mg) preferred for elderly or debilitated patients 2

Monitoring Strategy

• Check INR within 3-7 days after resuming warfarin to ensure the patient remains in therapeutic range 2
• Once stable, INR monitoring can be performed at intervals of 1-4 weeks, depending on the patient's reliability and stability 2
• The goal is to maintain time in therapeutic range (TTR) ≥65-70%, ideally ≥70% 1, 4

Common Pitfalls to Avoid

• Do not give a loading dose or double dose to "catch up" after withholding warfarin, as the INR is already therapeutic 2
• Do not reduce the dose simply because warfarin was recently withheld—the current INR of 2.7 indicates appropriate anticoagulation 1
• Do not target a lower INR range (such as 1.5-2.5) in this patient, as an INR range of 2.0-3.0 provides maximum stroke protection with acceptable bleeding risk 1
• Avoid the misconception that elderly patients require lower INR targets; the standard 2.0-3.0 range applies unless there is documented high bleeding risk 1, 4

Rationale for This Approach

• The American College of Cardiology and European Society of Cardiology guidelines consistently recommend INR 2.0-3.0 for all patterns of atrial fibrillation, including paroxysmal and persistent AF 1
• An INR below 2.0 provides only approximately 80% of the stroke protection achieved with INR 2.0-3.0, while INR above 3.5-4.0 significantly increases bleeding risk, particularly intracranial hemorrhage 1
• The anticoagulant effect of warfarin persists beyond 24 hours, so resuming the maintenance dose when INR is 2.7 will maintain therapeutic anticoagulation without overshooting 2