The standard is still the standard or why an INR of 2-3 is still the optimal intensity for secondary prevention of venous thromboembolism.

The optimal intensity of warfarin anticoagulation for secondary prevention of venous thromboembolism is debatable. Recent studies have shed light on the issue. The two pivotal studies, ELATE and PREVENT, are reviewed and discussed. Although the ELATE and PREVENT studies offer different conclusions, the results of the two studies are consistent with each other. Low intensity warfarin is more efficacious than placebo, although it is less efficacious than standard intensity and offers no safety advantage. For long term secondary prophylaxis of spontaneous venous thromboembolism, the optimal INR intensity of warfarin remains 2.0-3.0.