Coumadin Managment Clinic
Coumadin (Warfarin) is a prescription medication used to prevent harmful blood clots from forming or growing larger. Beneficial blood clots prevent or stop bleeding, but harmful blood clots can cause a heart attack, stroke, deep vein thrombosis or pulmonary embolism. Because Coumadin interferes with the formation of blood clots, it is called an anticoagulant. Many people refer to anticoagulants as “blood thinners;” however, Coumadin does not thin the blood but instead causes the blood to take longer to form a clot.
The goal of Coumadin therapy is to decrease the clotting tendency of blood, not to prevent clotting completely. Therefore, the effect of Coumadin must be monitored carefully with blood testing. On the basis of the results of the blood test, your daily dose of Coumadin will be adjusted to keep your clotting time within a target range. The blood test used to measure the time it takes for blood to clot is referred to as a prothrombin time test, or protime (PT).
The INR is a standardized way of expressing the PT value. It is important to monitor the INR (at least once a month and sometimes as often as twice weekly) to make sure that the level of Coumadin remains in the effective range. If the INR is too low, blood clots will not be prevented, but if the INR is too high, there is an increased risk of bleeding. This is why those who take warfarin must have their blood tested so frequently.