一位有第二型糖尿病的 55 歲男性，每日服用口服 metformin。他昨日因腹部電腦斷層接受了靜脈含碘對比劑注射。護理師檢閱今日用藥紀錄時，應如何處理 metformin 排定劑量？
A 55-year-old male with type 2 diabetes takes oral metformin daily. Yesterday he received IV iodinated contrast media for an abdominal CT scan. Reviewing today's medication administration record, how should the nurse proceed regarding the scheduled metformin dose?
- AVigorously administer the scheduled Metformin along with a large glass of orange juice, as the iodine dye aggressively strips all glucose from the bloodstream, risking a fatal hypoglycemic coma.強烈給予預定劑量的 Metformin 並搭配一大杯柳橙汁，因為碘染料會猛烈清除血液中的所有葡萄糖，導致致命性低血糖昏迷。
- BResolutely withhold the Metformin dose for a minimum of 48 hours post-procedure and notify the provider to restart it only after serum laboratory results confirm absolutely normal baseline kidney functions.✓ 正解堅決在術後至少 48 小時內暫停給予 Metformin 劑量，並通知醫師，僅在血清實驗室結果確認基線腎功能完全正常後才重新開始給藥。
- CAdminister the scheduled Metformin normally because it profoundly protects the delicate nephrons from the corrosive effects of the heavy iodine contrast.正常給予預定劑量的 Metformin，因為它能深層保護脆弱的腎元免受腐蝕性重碘對比劑的影響。
- DCall the physician to have the dose dramatically massively doubled today, as iodine aggressively causes acute insulin resistance in diabetic clients.打電話給醫師，要求今天大幅將劑量加倍，因為碘會猛烈導致糖尿病病患產生急性胰島素抗性。
Metformin 雖為糖尿病一線用藥，但與含碘對比劑併用具乳酸中毒（lactic acidosis）風險。對比劑可能引起短暫性急性腎損傷（contrast-associated AKI），導致 metformin 無法經由腎臟正常排除，乳酸會在體內累積。標準做法（依 ACR 指引）：對於 eGFR < 30 或已知腎功能受損之病人，應於對比劑使用後停用 metformin 至少 48 小時，並待腎功能（creatinine、eGFR）確認正常後再恢復用藥（B）。對於 eGFR 正常者，停藥指引較為寬鬆，但臨床仍以保守處置為主。其他選項：C. metformin 並無腎保護作用；B. 對比劑不會誘發低血糖；C. 加倍劑量會增加乳酸中毒風險，是錯誤的處置。
Metformin should be withheld for 48 hours after administration of iodinated contrast media due to the risk of contrast-induced acute kidney injury, which can lead to metformin accumulation and lactic acidosis. The medication should only be restarted after renal function tests confirm that kidney function has returned to baseline levels.
世界通用藥理規定。「遇到打顯影劑(CT) 就要問病患有沒有吃 Metformin，如果有，前後皆必須停藥 48 小時防乳酸中毒」。這也是美國護理、放射科技師與台灣病房護理師絕對不能犯的低級給藥失誤。