If your dosage of a blood-thinning medication, such as warfarin (Coumadin®, Jantoven®), is too high or too low, it may lead to potentially dangerous complications. To help ensure your dosage is at a safe and effective amount, you will need to have routine blood tests to check your international normalized ratio (INR). This test measures how long it takes your blood to clot.
Maintaining your levels of INR within a goal range can help prevent serious problems. For example, if your INR is too high, it means that it takes a long time for your blood to clot. This may increase your risk for dangerous, uncontrollable bleeding. However, if INR levels are too low, you may have an increased risk for blood clots and strokes.
(For more information on this topic, click INR. This selection from the eMedTV site explains how your INR level is determined, how often you need to take these tests, and why some foods and medications may affect your results.)