托拉塞米
**托拉塞米 (Torsemide)** 是一種強效的**環利尿劑**，在獸醫學中主要用作犬貓**充血性心衰竭 (CHF)** 的「救援」或輔助治療。 * **效力**：效力約為呋塞米 (Furosemide) 的 **10 倍**。 * **作用時間**：作用時間較長（約 12 小時），可減少給藥頻率。 * **保鉀作用**：在犬隻中，其排鉀量低於呋塞米，但仍需密切監測。 > **臨床重點**：當病患對呋塞米產生**利尿劑抗性**時，托拉塞米越來越受到青睞，有助於控制嚴重的肺水腫和腹水。
作用機制: Torsemide acts on the **thick ascending limb of the loop of Henle** in the kidneys. * It reversibly binds to and inhibits the **Na⁺/K⁺/2Cl⁻ (NKCC2) cotransporter** at the chloride-binding site → prevents the reabsorption of sodium and chloride. * This disruption abolishes the hypertonic medullary interstitium → prevents the concentration of urine → results in profound **diuresis** (excretion of water). * It also increases the renal excretion of potassium, calcium, magnesium, hydrogen, ammonium, and bicarbonate. In dogs, its potassium-wasting effect is notably less severe than that of furosemide.
各物種劑量
- Adjunctive treatment of refractory congestive heart failure · 0.2-0.3 mg/kg · PO · q12-24h · When other diuretics have become ineffective
- Congestive heart failure · 0.2 mg/kg · PO · once a day to three times a day
- Adjunctive treatment of refractory congestive heart failure · 0.2-0.3 mg/kg · PO · q12-24h · When other diuretics have become ineffective
- Congestive heart failure · 0.2 mg/kg · PO · once a day to three times a day
劑量為合格獸醫專業人員的臨床參考。請務必對照最新藥品仿單及個別病患確認。
給藥途徑
禁忌症
- Known hypersensitivity to torsemide or other sulfonylureas
- Anuric patients
不良反應
- Fluid and electrolyte abnormalities (hyponatremia, hypocalcemia, hypokalemia, hypomagnesemia)
- Prerenal azotemia (secondary to dehydration)
- Gastrointestinal disturbances
- Hematologic effects (anemia, leukopenia)
- Weakness
- Restlessness
- Ototoxicity (rare, associated with rapid IV administration)
藥物相互作用
- ACE Inhibitors (e.g., enalapril, benazepril) · Increased risks for hypotension, particularly in patients who are volume or sodium depleted secondary to diuretics
- Aminoglycosides (gentamicin, amikacin, etc.) · May increase the ototoxic or nephrotoxic risks of aminoglycosides
- Amphotericin B · May increase the risk for nephrotoxicity development
- Digoxin · Can increase the area under the curve of torsemide by 50%; torsemide-induced hypokalemia may increase the potential for digoxin toxicity
- Lithium · Torsemide may reduce lithium clearance
- NSAIDs · Some NSAIDs may reduce the natriuretic effects of torsemide
- Probenecid · Can reduce the diuretic efficacy of torsemide
- Salicylates · Torsemide can reduce the excretion of salicylates
監測
- Serum electrolytes (especially potassium, sodium, calcium, magnesium)
- BUN and creatinine
- Blood glucose (if diabetic)
- Hydration status
- Blood pressure (if indicated)
- Clinical signs of edema and patient weight
過量
In dogs, the oral LD50 is >2 grams/kg. **Fluid and electrolyte imbalance** is the most likely risk associated with an overdose. * Consider gut emptying protocols for very large or quantity unknown ingestions. * Acute overdoses should generally be managed by observation with fluid, electrolyte, and acid-base monitoring. * Supportive treatment should be initiated if required.
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。