Warfarin (historically marketed as Coumadin® and currently available as Jantoven®) remains an important anticoagulant used to reduce thromboembolic risk in individuals requiring long-term anticoagulation. Its narrow therapeutic range and associated bleeding risk require careful monitoring and coordinated care in ambulatory settings. This course reviews the mechanism of action of warfarin, indications and contraindications, INR monitoring, dietary considerations, medication interactions, and strategies to reduce complications.