Guides warfarin initiation and early dose adjustment. Starting dose: 5 mg/day for healthy adults <60; 2.5–5 mg/day for elderly, frail, or nutritionally compromised patients. Check INR at day 3–4 and adjust to target INR 2.0–3.0 (most indications) or 2.5–3.5 (mechanical mitral valve, recurrent VTE). Bridging with heparin required if thromboembolic risk is high.
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