In 2012, the American College of Chest Physicians (ACCP) published a guideline to help with the management of anticoagulation therapy. This executive summary clarifies many questions that come up routinely when a patient’s INR is not within the therapeutic window.

What should you do for a patient taking a vitamin K antagonist (VKA) with a previously stable therapeutic INR who presents with a single out-of-range INR which is ≤ 0.5 above or below therapeutic window?

Two studies have found no benefit in making micro adjustments in this group of patients.

After a patient has completed a 3 month course of warfarin for a first-time provoked DVT, can the warfarin be stopped abruptly or does it need to be tapered?

Although it was thought that stopping warfarin could create a rebound prothrombotic state (since the procoagulants II, IV, IX, and X come back on line at different rates than the anticoagulants protein C and S), the evidence says that the thromboembolic rate is not significantly different whether you taper or stop all at once.

No taper is needed after completing the course of therapy.

How should you manage an asymptomatic patient whose INR is between 4.5 and 10?

Once the INR gets over 4.5, the bleeding risk increases. 4.5 appears to be the inflection point above which bleeding starts to become a concern.

The ACCP recommends stopping the warfarin and letting the INR trickle down. They advise against administering vitamin K for asymptomatic patients with an INR between 4.5 and 10. When the INR is in this range, the use of vitamin K does not decrease the rate of bleeding or increase the rate of thromboembolism.

It is important to determine why the INR is elevated. Is the patient taking the medications improperly? Were they prescribed a new medication with interferes with warfarin metabolism?