琥珀膽鹼
氯化琥珀膽鹼是一種超短效的去極化型骨骼肌鬆弛劑（麻痺劑）。 **關鍵臨床要點：** * **無鎮痛或鎮靜作用：** 琥珀膽鹼絕對不提供任何止痛或意識喪失的效果。病患完全清醒且能感覺疼痛，但全身癱瘓。必須*始終*與適當的鎮靜劑、麻醉劑和鎮痛劑併用。 * **需要呼吸器支持：** 因為它會麻痺橫膈膜和肋間肌，在藥效消退前必須進行機械通氣。 * **臨床用途：** 主要用於需要短期肌肉鬆弛的氣管插管（快速順序插管）、外科/診斷程序，或減少抽搐時的肌肉收縮。 * **物種差異：** 雖然在人類和多數動物中作用時間極短（2-3分鐘），但狗會表現出特異性的延長作用時間（約20分鐘）。 * **現代應用：** 在獸醫學中，其使用已很大程度上被副作用較少且可逆的非去極化型藥物（如阿曲庫銨、羅庫溴銨）所取代。
作用機制: Succinylcholine acts as a depolarizing neuromuscular blocker. * **Binding:** It acts as a structural analog of acetylcholine (ACh) and binds to **nicotinic acetylcholine receptors (nAChRs)** at the motor endplate of the neuromuscular junction. * **Depolarization:** Unlike ACh, which is instantly degraded by acetylcholinesterase, succinylcholine remains bound, causing prolonged depolarization of the muscle membrane. This initial depolarization manifests clinically as transient muscle twitches (**fasciculations**). * **Paralysis:** Because the membrane cannot repolarize, it becomes unresponsive to subsequent ACh release → **flaccid paralysis** (Phase I block). * **Metabolism:** The blockade persists until succinylcholine diffuses away from the receptor and is rapidly hydrolyzed by **plasma pseudocholinesterase** (butyrylcholinesterase) in the blood.
各物種劑量
- Muscle relaxation · 0.06 mg/kg · IV · Single dose
- Muscle relaxation · 0.11 mg/kg · IV · Single dose
- Muscle relaxation · 0.088-0.11 mg/kg · IV, IM · Single dose · See Precautions. ARCI UCGFS Class 2 Drug. 0.088 mg/kg IV may paralyze skeletal muscles without causing respiratory depression, but higher doses cause apnea.
- Muscle relaxation · 0.07 mg/kg · IV · Single dose
- Muscle relaxation · 0.22 mg/kg · IV · Single dose
- To relax an animal to allow intubation · 0.5-1 mg/kg · IM · Single dose · Especially helpful with turtles and crocodilians.
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
- Severe liver disease
- Chronic anemias
- Chronic malnourishment
- Glaucoma or penetrating eye injuries
- Predisposition to malignant hyperthermia
- Increased CPK values with resultant myopathies
- Recent use of organophosphate agents
不良反應
- Muscle soreness
- Histamine release
- Malignant hyperthermia
- Excessive salivation
- Hyperkalemia
- Rash
- Myoglobinemia
- Myoglobinuria
- Bradycardia
- Tachycardia
- Hypertension
- Hypotension
- Arrhythmias
藥物相互作用
- Amphotericin B · May increase succinylcholine's effects by causing electrolyte imbalances
- Digoxin · Succinylcholine may cause a sudden outflux of potassium from muscle cells, causing arrhythmias in digitalized patients
- Opiates · Potential for increased incidences of bradycardia and sinus arrest
- Thiazide Diuretics · May increase succinylcholine's effects by causing electrolyte imbalances
- Aminoglycosides · May increase or prolong neuromuscular blockade
- Inhalant Anesthetics (Isoflurane, Desflurane) · May increase or prolong neuromuscular blockade
- Antiarrhythmics (Quinidine, Lidocaine, Procainamide) · May increase or prolong neuromuscular blockade
- Beta-Adrenergic Blockers · May increase or prolong neuromuscular blockade
- Corticosteroids · May increase or prolong neuromuscular blockade
- Magnesium Salts · May increase or prolong neuromuscular blockade
- Organophosphates · May increase or prolong neuromuscular blockade (Contraindicated)
監測
- Level of muscle relaxation
- Cardiac rate and rhythm (ECG)
- Respiratory depressant effect (Apnea)
- Oxygenation (Pulse oximetry) and Ventilation (Capnography)
- Body temperature (risk of malignant hyperthermia)
過量
Inadvertent overdoses, or standard doses in patients deficient in pseudocholinesterase, may result in **prolonged apnea**. * **Treatment:** Mechanical ventilation with 100% O2 must be maintained until full spontaneous recovery occurs. * **Phase II Block:** Repeated or prolonged high dosages may cause patients to convert from a depolarizing (Phase I) block to a non-depolarizing-like (Phase II) block.
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。