What does an increase in INR indicate in a patient on warfarin therapy?

An increase in INR, or International Normalized Ratio, signifies a heightened level of anticoagulation in a patient undergoing warfarin therapy. Warfarin is an anticoagulant medication that works by inhibiting the synthesis of vitamin K-dependent clotting factors, which play a crucial role in the coagulation process. Monitoring INR helps determine the effectiveness of the therapy.

When the INR rises above the therapeutic range, it indicates that the patient's blood is taking longer to clot, thus increasing the anticoagulant effect. This is intentional for patients at risk for thromboembolic events, as higher INR values are associated with a greater likelihood of preventing thrombosis. However, it is vital to balance INR levels, as excessively high levels could lead to an increased risk of bleeding complications. Therefore, an increased INR while on warfarin is expected to denote increased anticoagulation, allowing healthcare providers to adjust dosages as necessary to maintain the desired therapeutic range.