The increase of geriatric and diabetic patients with poor vasculature brings about a corresponding increase in the use of synthetic vascular access grafts. Synthetic vascular accesses are plagued with numerous problems in maintaining patency. As a result, many practitioners use warfarin sodium. Coumadin, because of its predictability and bioavailability to interrupt the coagulation cascade to prevent thrombus formation. This article includes actions, interactions, monitoring, and adverse effects of this drug.