一位躁鬱症病人被處方服用碳酸鋰（Lithium Carbonate）。病人下列哪項陳述顯示需要進一步的衛教？
A client is diagnosed with bipolar disorder and is prescribed Lithium Carbonate. Which of the following statements by the client indicates a need for further teaching?
- AI will have my blood levels checked regularly我會定期抽血檢查藥物濃度
- BI will call my doctor if I have persistent diarrhea or vomiting如果我有持續性的腹瀉或嘔吐，我會打電話給醫生
- CI will use a low-sodium diet to help keep my blood pressure down✓ 正解我會採用低鈉飲食來幫助控制血壓
- DI will make sure to drink 2 to 3 liters of water every day我會確保每天喝 2 到 3 公升的水
鋰鹽（Lithium）的代謝與鈉離子（Sodium）在腎臟的排泄密切相關。鋰鹽與鈉在腎小管競爭重吸收，當人體攝取「低鈉」或發生脫水（如流汗、嘔吐、腹瀉）時，腎臟會為了保留鈉而同時保留鋰，進而導致鋰鹽在體內蓄積，引發鋰中毒。因此，服用鋰鹽的病人絕對不能刻意限制鈉攝取（C），必須維持正常且穩定的鈉鹽攝入。選項 D（足量飲水）是正確的，可預防脫水；選項 A（定期抽血）是必須的，因為鋰鹽治療視窗狹窄（0.6-1.2 mEq/L）；選項 B（腹瀉嘔吐要通報）正確，因為這會導致體液與電解質流失，迅速提升血鋰濃度。此題考點在於「藥物與電解質的交互作用」。
The metabolism of lithium is closely related to renal excretion of sodium. Lithium and sodium compete for reabsorption in the renal tubules. When a person ingests a low-sodium diet or becomes dehydrated (from sweating, vomiting, or diarrhea), the kidneys retain sodium and simultaneously retain lithium, leading to accumulation of lithium in the body and resulting in lithium toxicity. Therefore, a patient on lithium must never deliberately restrict sodium intake (C) and must maintain a normal and stable sodium intake. Option D (adequate water intake) is correct, as it prevents dehydration; option A (regular blood draws) is essential, because lithium has a narrow therapeutic window (0.6-1.2 mEq/L); option B (reporting diarrhea or vomiting) is correct, because these lead to fluid and electrolyte losses and rapidly raise the blood lithium level. The focus of this question is the interaction between medications and electrolytes.
美國 NCLEX 非常強調 Lithium 與 Sodium 的「反向關係」；台灣臨床衛教有時較著重在副作用（如手抖、多尿），但對於「不可限鈉」的強調程度可能因各病房慣例而異。NCLEX 必考此關聯性。