Coumadin (Warfarin) is commonly prescribed for these patients and requires close monitoring. Illnesses, many medications and some foods influence Coumadin’s effect on blood clotting. Regular blood testing and dose adjustments are necessary to avoid bleeding while still preventing undesired clotting. Some patients need frequent medication adjustments. That’s where the expertise of the Georgetown Coumadin Clinic comes in. Our service is staffed by nurse clinicians with advanced clinical training in anticoagulation management.