This lesson focuses on the oral anticoagulants — warfarin and the direct oral anticoagulants (DOACs) — which carry patients from the acute, hospital phase of anticoagulation into long-term management at home. Where the heparins covered in Lesson 1 act within minutes, the oral agents are designed for sustained, outpatient use, which shifts the nurse's emphasis toward monitoring, drug and food interactions, and patient teaching. Warfarin and the DOACs are prescribed to prevent stroke in atrial fibrillation, to treat and prevent deep vein thrombosis and pulmonary embolism, and to protect mechanical heart valves (a setting where warfarin remains the standard because DOACs are not approved for mechanical valves). Like all anticoagulants, they prevent new clot formation rather than dissolving clots that already exist. Warfarin is the older, vitamin K–dependent agent. It is inexpensive and fully reversible, but it has a slow onset, a narrow therapeutic window, and an enormous list of food and drug interactions, all of which demand regular INR monitoring. The DOACs — rivaroxaban, apixaban, and dabigatran — were developed to overcome warfarin's drawbacks: they have a predictable effect,...