一位第二型糖尿病病人使用 Metformin。護理師應將下列哪種臨床表現識別為需立即通報的副作用？
A client with type 2 diabetes mellitus is prescribed metformin. Which clinical manifestation should the nurse identify as an adverse effect requiring immediate reporting?
- AEpisodic hypoglycemia間歇性低血糖。
- BAbdominal bloating and flatulence腹部脹氣和腸氣增多。
- CMild metallic taste in the mouth口中輕微金屬味。
- DMuscle pain, malaise, and respiratory distress✓ 正解肌肉疼痛、倦怠和呼吸困難。
Metformin 最嚴重的副作用是乳酸中毒（Lactic Acidosis），其臨床表現包括非特異性的肌肉疼痛、極度倦怠、呼吸急促或困難。這與藥物累積導致體內酸鹼平衡失調有關，為危及生命的急症。其他選項如腸胃道不適或口中有金屬味為常見副作用，通常可自行緩解。
The most serious adverse effect of metformin is lactic acidosis, the clinical manifestations of which include nonspecific muscle pain, profound fatigue, and rapid or labored breathing. This is related to drug accumulation that disrupts acid-base balance and constitutes a life-threatening emergency. Other options, such as gastrointestinal discomfort or a metallic taste in the mouth, are common adverse effects that usually resolve on their own.
台灣醫護人員特別警惕腎功能不佳病人使用 Metformin 時的乳酸中毒風險，並強調劑量調整。