トラセミド
**トラセミド (Torsemide)** は、主に犬や猫の**うっ血性心不全 (CHF)** に対する「レスキュー」または補助療法として獣医療で使用される強力な**ループ利尿薬**です。 * **効力**: フロセミドの**約10倍**の効力があります。 * **持続時間**: 作用時間が長く（約12時間）、投与回数を減らすことができます。 * **カリウム保持性**: 犬ではフロセミドに比べてカリウムの排泄が少ないですが、モニタリングは依然として重要です。 > **臨床のポイント**: フロセミドに対する**利尿薬抵抗性**が生じた場合、重度の肺水腫や腹水の管理にトラセミドが好まれることが増えています。
作用機序: 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.
動物種別の用量
- 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
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
禁忌
- Known hypersensitivity to torsemide or other sulfonylureas
- Anuric patients
有害事象
- 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)
薬物相互作用
- 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
モニタリング
- 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
過量投与
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 の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。