Warfarin: Vitamin K Antagonist
Target INR for atrial fibrillation: 2.0-3.0
Dosage: 5 mg daily for the first 3 days, then assess INR
If age >65 years, debilitated, congestive heart failure or liver disease, then 2.5 mg daily for 3 days and assess INR. Appropriate initial dose and close monitoring of anticoagulation status are of particular importance due to delayed response in INR and drug-drug interactions.
Dose adjustment algorithm: www.warfarindosing.org
Duke University algorithm:
Management of elevated INR with or without bleeding: