INRtavoite

INR target, or INRtavoite in Finnish medical usage, refers to the therapeutic range of the international normalized ratio used to guide anticoagulant therapy with vitamin K antagonists such as warfarin. The INR standardizes how long blood takes to clot, allowing clinicians to adjust medication to achieve and maintain a chosen target range.

The purpose of the INR target is to balance the risk of thrombosis against the risk of bleeding. By keeping the INR within a specified interval, patients on anticoagulants can reduce the chance of clot formation while limiting excessive bleeding. The exact target depends on the underlying condition, patient risk factors, and the type of valve or prosthesis if present.

Common targets are typically described in ranges. For many indications, such as nonvalvular atrial fibrillation or venous thromboembolism, an INR of about 2.0 to 3.0 is used. Higher targets, for example around 2.5 to 3.5, may be chosen for certain mechanical heart valves or high-thrombotic-risk situations, while some patients may have lower targets based on individual risk profiles. The chosen range is determined by guidelines and clinician judgment.

Monitoring is essential, with periodic blood tests to measure INR. After starting or changing therapy, testing is more frequent (often weekly) and becomes less frequent once INR stability is achieved (typically every 2 to 4 weeks). Factors such as drug interactions, diet (vitamin K intake), liver function, illness, and adherence can cause INR to drift.

DOACs (direct oral anticoagulants) do not require INR monitoring, and the concept of an INR target applies specifically to vitamin K antagonists.