A Future Without Warfarin/Coumadin

I will make a prediction that I am very confident will eventually be true, it could be a few years from now, but I think we will see it soon and that is a world without Coumadin, also known as Warfarin. Warfarin is used for many disease states, its goal is to prevent strokes in patients with atrial fibrillation (fast and irregular heart beat that can be very discomforting), to treat clots in the legs (venous thromboembolism), treat arterial clots in the arms and legs, and to also treat patients who have have heart failure and sickle cell disease-related pulmonary hypertension. The main problem with Coumadin/Warfarin is that one has to monitor the dose with blood test almost on a weekly basis and the drug fluctuates on a daily basis based on the metabolism of the drug within an individual patient, which usually can not be predicted or can be based on the patient's diet. If a patient consumes a great deal of leafy green vegetables, which contain a high amount of vitamin K, they will be at risk of having low levels of activity of coumadin and this be undermedicated, which will still increase their risk for stroke of clots in the legs. Even in the best case scenario, coumadin's ability to prevent stroke is about 80%, but in most patient who have fluctuate levels of the drug in their system, the protection that they achieve from the drug is about 60-70%.

Furthermore, other problems with coumadin is that it interacts with many medications. I recall when I was in medical school and was called by my sister to go see my aunt at the hospital because her arm was all bruised and her doctors did not know why, they thought that she may have leukemia because they did not know she was on coumadin, when that was discovered, they realized that a few days before she was admitted to the hospital, she had been given an antibiotic called Bactrim, which interacts with coumadin by decreasing its metabolism, so that the levels were much higher than expected. After a few days, she was back to normal.

A recent study that was presented at the European Heart Society Meeting this fall presented data on a new oral drug called Dabigitran, which is a direct oral thrombin (clot) inhibitor, which was compared to coumadin and was shown to have improved outcomes compared to coumadin in regards of less stroke and at the lower dose, even less bleeding. This drug is taken twice a day, it is being used in Europe. It does not require any monitoring and has minimal diet and drug interactions. This is an ideal replacement for coumadin and others are in the pipeline as well. This drug has not yet been approved by the FDA, but may be approved by the end of 2010.

References:
http://www.theheart.org/article/1031821.do