Which of the following are indications for warfarin therapy?

• A. Atrial fibrillation, mechanical heart valves, VTE, protein C/S disorders
• B. Myocardial infarction
• C. Pregnancy
• D. Benign prostatic hyperplasia

Answer: (A)

Warfarin is used when there is a high risk of systemic embolism or recurrent thrombosis due to certain conditions. It’s a vitamin K antagonist that lowers the production of vitamin K–dependent clotting factors, helping prevent clot formation in at-risk situations.

The listed indications—atrial fibrillation (to prevent cardioembolic stroke), mechanical heart valves (to prevent valve-related embolism), venous thromboembolism (treatment and prevention of recurrence), and inherited thrombophilias such as protein C or protein S deficiencies—are all established scenarios where long-term anticoagulation with warfarin is appropriate.

Why the others aren’t general indications: myocardial infarction by itself isn’t a standard long-term warfarin indication; antiplatelet therapy is primary, though warfarin may be added in specific complex cases (and not as a general rule). Pregnancy is avoided with warfarin due to teratogenic risks; safer alternatives like heparin are used instead. Benign prostatic hyperplasia does not involve thrombotic risk that necessitates anticoagulation.

So the combination of AF, mechanical valves, VTE, and protein C/S disorders represents genuine indications for warfarin therapy.