Warfarin
An oral anticoagulant that inhibits vitamin K-dependent clotting factors; used to prevent thromboembolic events.
Warfarin blocks hepatic synthesis of clotting factors II, VII, IX, and X by competitively inhibiting vitamin K epoxide reductase. Its effect is measured by the INR, with a typical therapeutic target of 2–3. Onset is delayed 2–5 days; the antidote is vitamin K (phytonadione), and fresh frozen plasma is used for rapid reversal.
Warfarin has dozens of drug and food interactions that shift the INR unpredictably. Patient education on consistent diet, reporting unusual bleeding, and never skipping doses without guidance is a nursing priority.
(Placeholder study content — expanded in the content build step.)
Source: ATI Pharmacology for Nursing Care, 10th ed.
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