卡托普利
卡托普利 (Captopril) 是一種含有巰基的第一代**血管張力素轉化酶 (ACE) 抑制劑**。它最初是從南美蝮蛇的毒液中分離出來的胜肽衍生物。雖然作為首個上市的 ACE 抑制劑具有歷史意義，但由於其半衰期較短（通常需要每天給藥三次）且不良反應（特別是狗的胃腸道不適）發生率較高，目前在獸醫學中的應用已大部分被**依那普利 (Enalapril)** 和**貝那普利 (Benazepril)** 等較新的藥物所取代。 **臨床要點：**與依那普利不同，卡托普利本身即為活性藥物，不需要經過肝臟生物轉化為活性代謝物即可發揮作用。
作用機制: Captopril acts as a competitive inhibitor of **angiotensin-converting enzyme (ACE)**, for which it has a much higher affinity than the natural substrate, angiotensin-I. * **Angiotensin I** → (blocked by ACE) → **Angiotensin II** (a potent vasoconstrictor). * The reduction in Angiotensin II leads to **vasodilation**, decreasing total peripheral resistance, pulmonary vascular resistance, and blood pressure. * Decreased Angiotensin II also reduces **aldosterone** secretion, leading to decreased sodium and water retention, while increasing plasma renin activity. * Cardiovascular benefits in CHF include increased cardiac output, stroke volume, and exercise tolerance with little to no change in heart rate.
各物種劑量
- CHF / Hypertension · 1/4 to 1/2 of a 12.5 mg tablet PO q8-12h · PO · q8-12h
- Dilative, restrictive or hypertrophic cardiomyopathy · 0.55-1.54 mg/kg PO q8-12h · PO · q8-12h
- CHF / Hypertension · 0.5-2 mg/kg PO three times daily · PO · TID
- CHF / Hypertension · 0.5-2 mg/kg PO q8-12h · PO · q8-12h
劑量為持牌獸醫專業人員的臨床參考。請務必對照最新藥品說明書及個別病患確認。
給藥途徑
禁忌症
- Hypersensitivity to ACE inhibitors
不良反應
- Hypotension
- Renal failure
- Hyperkalemia
- Vomiting
- Diarrhea
- Skin rashes (reported in humans, not dogs)
- Neutropenia/agranulocytosis (rare, reported in humans)
藥物相互作用
- Antacids · Reduced oral absorption of captopril; separate dosing by at least two hours.
- Cimetidine · Concomitant use has caused neurologic dysfunction in human patients.
- Digoxin · Digoxin levels may increase 15-30%; monitor serum digoxin levels.
- Diuretics · Concomitant use may cause hypotension; titrate dosages carefully.
- NSAIDs · May reduce the clinical efficacy of captopril when used as an antihypertensive agent.
- Potassium or Potassium-Sparing Diuretics (e.g., spironolactone) · Increased risk of developing hyperkalemia.
- Probenecid · Can decrease renal excretion of captopril, possibly enhancing clinical and toxic effects.
- Vasodilators (e.g., prazosin, hydralazine, nitrates) · Concomitant use may cause additive hypotension; titrate dosages carefully.
監測
- Clinical signs of CHF (respiratory rate/effort, exercise tolerance)
- Blood pressure (especially if treating hypertension or if signs of hypotension arise)
- Serum electrolytes (monitor for hyperkalemia)
- Renal panel (Creatinine, BUN)
- Urine protein
- CBC with differential (periodic)
過量
The primary concern in an overdose situation is **hypotension**. * **Treatment:** Supportive treatment with volume expansion using normal saline is recommended to correct blood pressure. * **Toxicity thresholds:** Dogs given 1.5 g/kg orally developed emesis and decreased blood pressure. Dogs receiving doses greater than 6.6 mg/kg q8h may develop renal failure.
VetSheet 藥物參考供持牌獸醫專業人員作臨床決策輔助之用,不能取代專業判斷或廠方最新藥品說明書。