依卓酚 (Edrophonium)
依卓酚是一種短效的注射用抗膽鹼酯酶藥物，在獸醫學中主要用於透過「Tensilon 測試」來推斷診斷重症肌無力（Myasthenia Gravis, MG）。雖然它也可用於逆轉非去極化神經肌肉阻斷劑的作用，或治療特定的室上性心搏過速（SVT），但由於其作用時間極短，臨床上通常會選擇作用時間較長的替代藥物（如新斯狄明 Neostigmine）。
作用機制: Edrophonium acts as a rapid, reversible inhibitor of the enzyme **acetylcholinesterase**. **Mechanism of Action:** Edrophonium briefly attaches to **acetylcholinesterase** → inhibits its hydrolytic activity → **acetylcholine** accumulates in the synaptic cleft → prolonged and increased stimulation of nicotinic and muscarinic receptors. In patients with myasthenia gravis, the sudden surge of acetylcholine temporarily overcomes the autoimmune blockade/destruction of nicotinic receptors at the neuromuscular junction, leading to a rapid (but transient) return of muscle strength. Systemically, acetylcholine accumulation also causes parasympathomimetic effects including miosis, increased intestinal muscle tone, bronchoconstriction, salivation, and bradycardia.
各物種劑量
- Presumptive diagnosis of myasthenia gravis (MG) · 0.25 to 0.5 mg (total dose) · IV · Once · Patient is gently exercised until fatigued. Place indwelling catheter. Have atropine drawn up (0.02-0.04 mg/kg IV) in case cholinergic signs develop. Flush catheter with sterile saline, then immediately lightly exercise or encourage to rise.
- Presumptive diagnosis of myasthenia gravis (MG) · 0.1 mg/kg · IV · Once · Pre-treat with atropine (0.02-0.04 mg/kg IM or SC). In affected animals, paresis should resolve within one minute and effects should last for up to 15 minutes.
- Presumptive diagnosis of myasthenia gravis (MG) · 0.1-0.2 mg/kg · IV · Once · Patient is gently exercised until fatigued. Place indwelling catheter. Have atropine drawn up (0.02-0.04 mg/kg IV) in case cholinergic signs develop. Flush catheter with sterile saline, then immediately lightly exercise or encourage to rise.
- Presumptive diagnosis of myasthenia gravis (MG) · 1-10 mg (total dose) · IV · Once · Presumptive positive test results in transient improvement in clinical weakness.
- Presumptive diagnosis of myasthenia gravis (MG) · 0.1-0.2 mg/kg · IV · Once · Have atropine and endotracheal tube readily available in case of overdose.
- Presumptive diagnosis of myasthenia gravis (MG) · 0.1 mg/kg · IV · Once · Pre-treat with atropine (0.02-0.04 mg/kg IM or SC). In affected animals, paresis should resolve within one minute and effects should last for up to 15 minutes.
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
- Bronchial asthma
- Mechanical urinary tract obstruction
- Mechanical intestinal tract obstruction
- Known hypersensitivity to the drug
不良反應
- Urination
- Lacrimation
- Vomiting
- Defecation
- Bradycardia
- Bronchospasm
- Salivation
藥物相互作用
- Atropine · Antagonizes the muscarinic effects of edrophonium. Concurrent use should be done cautiously as atropine can mask the early clinical signs of a cholinergic crisis.
- Dexpanthenol · Theoretically may have additive cholinergic effects when used with edrophonium.
- Digoxin · Edrophonium's cardiac effects may be increased; excessive slowing of heart rate (bradycardia) may occur.
- Depolarizing Muscle Relaxants (e.g., succinylcholine, decamethonium) · Edrophonium may prolong the Phase I block of these agents.
- Non-depolarizing Muscle Relaxants (e.g., pancuronium, tubocurarine, vecuronium, atracurium) · Edrophonium antagonizes the neuromuscular blocking actions of these agents.
監測
- Cholinergic adverse effects (heart rate, respiratory rate/effort, salivation)
- Improvement of paresis (for 1-15 minutes) for presumptive diagnosis of myasthenia gravis
過量
Overdosage of edrophonium may induce a **cholinergic crisis**. **Clinical Signs of Toxicity (SLUDGE syndrome and beyond):** - **GI:** Nausea, vomiting, diarrhea, salivation - **Respiratory:** Increased bronchial secretions, bronchospasm, pulmonary edema, respiratory paralysis - **Ophthalmic:** Miosis, blurred vision, lacrimation - **Cardiovascular:** Bradycardia or tachycardia, cardiospasm, hypotension, cardiac arrest - **Musculoskeletal:** Muscle cramps, profound weakness, sweating (in animals with sweat glands) > **Treatment:** Consists of immediate respiratory and cardiac supportive therapy. Administer **atropine** IV to counteract severe muscarinic effects.
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。