Table of Contents

INR RANGES AND DURATION OF WARFARIN THERAPY

Indication Target INR Duration of Therapy
Low intensity therapy
Prophylaxis of hip surgery
1.6-2.3  Until patient is ambulatory and/or up to 4-6 weeks
Moderate intensity therapy

Treatment of DVT or PE    

   
  • Due to reversible risk factors
2.0-3.0 3 months
  • Idiopathic
2.0-3.0 6-12 months (may consider indefinite)
  • ³ 2 episodes, cancer
2.0-3.0 Indefinite
Cardioverson for atrial fibrillation 2.0-3.0  3 weeks prior and 4 weeks post cardioversion
 Chronic atrial fibrillation 2.0-3.0 Indefinite
 Tissue heart valves 2.0-3.0  3 months post surgery
Mechanical aortic valve1 (normal left atrial size and normal sinus rhythm) 2.0-3.0 Indefinite
Acute anterior myocardial infarction (MI) 2.0-3.0  3 months post MI (with ASA 81mg daily)2
High intensity therapy    
Mechanical mitral valve1 (or aortic valve with atrial fibrillation) 2.5-3.5 Indefinite
 1St Jude Medical bileaflet valve, Carbomedics bileaflet valve, Medtronic-Hall tilting disc valve

2long-term use recommended if meticulous INR monitoring is standard; target INR range 2.5-3.5 without concomitant aspirin or 2.0-3.0 with aspirin