病患開始服用華法林（Warfarin）。下列哪項飲食衛教是必要的？
A client is starting warfarin therapy. Which dietary instruction is essential?
- AIncrease intake of cranberry juice增加蔓越莓汁攝取量
- BSupplement with vitamin C daily每日補充維生素C
- CAvoid all green leafy vegetables避免所有綠色葉菜類蔬菜
- DMaintain a consistent intake of vitamin K✓ 正解維持維生素K攝取量的一致性
華法林（Warfarin）是維生素 K 拮抗劑，透過抑制肝臟合成依賴維生素 K 的凝血因子（II, VII, IX, X）來發揮抗凝血作用。臨床衛教的核心重點並非「禁止」攝取維生素 K，而是要求「維持攝取量的一致性」。維生素 K 的攝取波動會直接導致國際標準化比值（INR）劇烈變化，增加出血或血栓風險。護理師應教導病患保持綠色蔬菜攝取量穩定，醫師則根據穩定後的 INR 調整藥物劑量。
Warfarin is a vitamin K antagonist that exerts its anticoagulant effect by inhibiting hepatic synthesis of vitamin K-dependent clotting factors (II, VII, IX, X). The central focus of patient teaching is not to prohibit vitamin K intake, but to maintain a consistent intake. Fluctuations in vitamin K intake directly cause dramatic changes in the international normalized ratio (INR), increasing the risk of bleeding or thrombosis. The nurse should instruct the client to keep green vegetable intake stable, and the provider then adjusts the medication dose based on the resulting stable INR.
在美國，藥師（Pharmacist）常參與華法林門診（Anticoagulation Clinic）的劑量調整，護理師需強調病患在飲食改變時務必諮詢藥師或醫師，這與台灣多由醫師直接開立劑量的模式略有不同。