一位病人預計進行需注射靜脈顯影劑的診斷性檢查。護理師審視病人的用藥紀錄，發現其正在服用 metformin。哪項行動最為重要？
A client is scheduled for a diagnostic procedure with intravenous contrast media. The nurse reviews the client's medications and finds that the client is taking metformin. Which action is most important?
- AHold the metformin for 48 hours after the procedure✓ 正解在術後停用 metformin 48 小時
- BAdminister an extra dose of metformin after the procedure在術後給予額外劑量的 metformin
- CConfirm the metformin was held for 48 hours prior to the test確認 metformin 已在檢查前停用 48 小時
- DEnsure the client remains NPO for 12 hours確保病人禁食 12 小時
Metformin（美福明）與含碘顯影劑之間存在顯著的藥物交互作用。顯影劑可能導致急性腎損傷（Contrast-Induced Nephropathy），若在腎功能受損的情況下繼續服用 metformin，藥物會在體內蓄積，進而引發極高死亡率的併發症——乳酸中毒（Lactic Acidosis）。標準護理常規是：在檢查前視情況停藥，但在檢查後『必須』至少停藥 48 小時，直到確認腎功能恢復正常後才能重新開始服用。這題的關鍵在於『檢查後』的停藥時間。雖然檢查前停藥也很常見，但檢查後的監測對於預防致命副作用更為關鍵。護理師需評估病人的肌酸酐（Creatinine）水平。
There is a significant drug interaction between metformin and iodinated contrast media. Contrast may cause acute kidney injury (contrast-induced nephropathy); if metformin is continued in the setting of impaired renal function, the drug accumulates and can precipitate lactic acidosis, a complication with extremely high mortality. The standard nursing protocol is to withhold the drug before the study as indicated by the clinical situation, but it must be withheld for at least 48 hours after the procedure and not resumed until renal function has been confirmed to have returned to normal. The key point of this item is the duration of withholding the drug after the procedure. Although withholding before the study is also common, post-procedure monitoring is more critical for preventing the lethal adverse effect. The nurse must assess the patient's creatinine level.
美國放射學學會（ACR）指引對腎功能正常的病人已放寬檢查前停藥規定，但『檢查後視腎功能恢復情況才復藥』仍是核心。台灣大多數醫院仍嚴格執行前 24-48 小時及後 48 小時停藥的規定。