阿米洛利
阿米洛利是一種**保鉀利尿劑**，通常與其他更強效的利尿劑（如呋塞米或噻嗪類）合併使用，以控制水腫和腹水，同時防止鉀離子過度流失。由於單獨使用時利尿作用較弱，其主要的臨床價值在於減輕由環利尿劑引起的低鉀血症。 > **臨床警告：** 如果使用不當，特別是在腎功能不全或正在服用ACE抑制劑的病患中，可能會導致危及生命的高鉀血症。 **臨床提示：** 在慢性心臟衰竭的治療中，常以複方製劑（例如 co-amilofruse）的形式出現，以平衡鉀的排泄與保留。
作用機制: Amiloride acts directly on the **distal convoluted tubule** and **collecting duct** of the nephron. It blocks epithelial sodium channels (ENaC) → inhibits sodium absorption → decreases the electrical potential across the tubular epithelium → reduces the driving force for potassium and hydrogen ion secretion. This leads to a failure of the normal renal concentration gradient, resulting in **sodium loss** (mild diuresis) and **potassium retention**.
給藥途徑
禁忌症
- Hyperkalemia
- Severe renal impairment or anuria
- Addison's disease (hypoadrenocorticism)
- Concurrent use of potassium supplements (unless closely monitored)
不良反應
- Hyperkalemia
- Hyponatremia
- Gastrointestinal disturbances (nausea, vomiting, diarrhea)
- Dehydration
- Weakness or lethargy
藥物相互作用
- ACE Inhibitors (e.g., Enalapril, Benazepril) · Increased risk of severe hyperkalemia due to additive potassium-sparing effects. · major
- Potassium Supplements · Significant risk of hyperkalemia. · major
- NSAIDs · May reduce the diuretic effect of amiloride and increase the risk of nephrotoxicity and hyperkalemia. · moderate
- Spironolactone · Additive potassium-sparing effects leading to hyperkalemia. · major
監測
- Serum potassium levels
- Serum sodium levels
- Renal function panel (BUN, Creatinine)
- Hydration status
- Blood pressure
過量
Overdose primarily presents as **severe hyperkalemia**, **dehydration**, and **hyponatremia**. Clinical signs may include profound weakness, bradycardia, cardiac arrhythmias, and collapse. **Treatment:** Discontinue the drug immediately. Induce emesis or perform gastric lavage if ingestion is recent. Treat hyperkalemia aggressively (e.g., IV fluids, calcium gluconate, dextrose/insulin, or sodium bicarbonate as clinically indicated).
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