Which statement describes a typical initial warfarin dosing strategy and target INR?

• A. 10 mg daily with target INR 1-2
• B. 1 mg daily with target INR 3-4
• C. 15 mg daily with INR 2-5
• D. 3-5 mg daily initially with target INR 2-3

Answer: (D)

Starting warfarin safely hinges on a cautious, individualized initial dose to reach the therapeutic INR without overshooting. For most nonvalvular indications like atrial fibrillation or a first episode of VTE, the usual goal is an INR of about 2-3. Beginning with a modest daily dose, in the 3–5 mg range, provides a balance: it reduces the risk of a sudden overshoot to high INR while still allowing progress toward therapeutic anticoagulation. After starting, the INR is checked in a few days and the dose adjusted accordingly.

Lower starting doses (for example around 1 mg daily) can delay reaching the therapeutic range and prolong risk of clotting; very high initial doses (such as 10–15 mg daily) can push the INR into supra-therapeutic levels quickly, increasing bleeding risk. A target INR of 1-2 or as high as 3-4 or 2-5 is not standard for initial therapy in most patients; 2-3 remains the typical target during the initial stabilization period. Thus, starting 3–5 mg daily with a target INR of 2–3 best reflects common practice.