艾司洛爾
艾司洛爾是一種超短效、具心臟選擇性的**Beta-1 腎上腺素受體拮抗劑**。 在獸醫學中，它主要作為靜脈輸注，用於急性、短期控制室上性心搏過速 (SVTs)，如心房顫動、心房撲動和竇性心搏過速。它也常被用作**診斷性測試藥物**，以評估病患在轉換為長效口服 Beta 阻斷劑前，是否能有效且耐受 Beta 阻斷劑治療。這在患有肥厚型心肌病 (HCM) 的貓中特別有用，可評估 Beta 阻斷是否能減少動態左心室出口阻塞。 > **臨床要點：** 由於艾司洛爾會被紅血球酯酶迅速代謝，其作用在停止輸注後 10-20 分鐘內即會消退，這使其在重症病患的試驗性治療中具有極高的安全性。
作用機制: Esmolol competitively blocks **beta-1 adrenergic receptors** in the myocardium with minimal to no effect on beta-2 receptors at clinical doses. * **Negative Chronotropy:** Decreases heart rate by slowing sinoatrial (SA) node firing and increasing sinus cycle length. * **Negative Dromotropy:** Slows conduction velocity through the atrioventricular (AV) node and prolongs sinus node recovery time. * **Negative Inotropy:** Decreases myocardial contractility, which reduces myocardial oxygen demand. Unlike propranolol, esmolol lacks intrinsic sympathomimetic activity (ISA) and does not possess membrane-stabilizing (quinidine-like) or bronchoconstrictive effects.
各物種劑量
- HCM (to determine if beta-blockers will reduce dynamic left-ventricular outflow tract obstruction) · An initial loading dose of 0.25-0.5 mg/kg (250-500 micrograms/kg) administered IV as slow bolus over 1-2 minutes, then followed by a constant rate infusion of 10-200 micrograms/kg/minute. · IV · CRI
- Critical Arrhythmias · Loading dose of 200-500 micrograms/kg IV over 1 minute; followed by a constant rate IV infusion of 25-200 micrograms/kg/minute · IV · CRI
- Ultra-short acting beta blockade (ventricular arrhythmias) - Normal cardiac function · An initial loading dose of 0.25-0.5 mg/kg (250-500 micrograms/kg) administered IV as slow bolus over 1-2 minutes, then followed by a constant rate infusion of 10-200 micrograms/kg/minute; or Start CRI at 10-200 micrograms/kg/minute without the bolus loading dose. · IV · CRI · If no loading dose, maximal effect should occur in 10-20 minutes.
- Ultra-short acting beta blockade - Severe dilated cardiomyopathy or severe mitral regurgitation · Start CRI at 10-20 micrograms/kg/min and titrate upward every 10 minutes to an effective endpoint. · IV · CRI · Do not give loading dose.
- SVTs · 0.05-0.1 mg/kg (50-100 micrograms/kg) IV bolus over 2 minutes; repeat every 5 minutes to a maximum of 0.5 mg/kg (500 micrograms/kg). · IV · q5m
- Arrhythmia conversion · Give in incremental IV bolus doses of 0.05-0.1 mg/kg every 5 minutes up to a maximum dose of 0.5 mg/kg. · IV · q5m · Because esmolol's effects are short-lived, if arrhythmia conversion does not occur, other negative inotropes (e.g., diltiazem, or verapamil) can be safely used 30 minutes after esmolol.
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給藥途徑
禁忌症
- Overt cardiac failure
- 2nd or 3rd degree AV block
- Sinus bradycardia
- Cardiogenic shock
- Second or third-degree AV block
- Uncompensated congestive heart failure
- Hypotension
不良反應
- Hypotension
- Bradycardia
- Heart block
- Exacerbation of congestive heart failure
- Bronchospasm (at high doses where beta-1 selectivity is lost)
藥物相互作用
- Digoxin · Esmolol may increase serum digoxin levels up to 20%, but these drugs have been used together safely and effectively. · moderate
- Monoamine Oxidase Inhibitors (MAOIs) · Concurrent use is not recommended due to potential risk of hypertension.
- Morphine · May increase steady-state esmolol serum concentrations up to 50%; titrate esmolol dosage carefully.
- Reserpine · May see additive effects (hypotension, bradycardia) if used with esmolol.
- Vasoconstrictors/Inotropes (e.g., dopamine, epinephrine, norepinephrine) · If systemic vascular resistance is high, there is an increased risk for blocked cardiac contractility; esmolol is not recommended to control SVTs in patients receiving these drugs.
- Verapamil · In humans, particularly with severe cardiomyopathy, cardiac arrest has occurred (rarely). · major
- Calcium channel blockers (e.g., Diltiazem, Verapamil) · Additive negative inotropic and chronotropic effects; risk of severe bradycardia and hypotension · major
- Alpha-2 agonists (e.g., Dexmedetomidine) · Increased risk of severe bradycardia · major
- Sympathomimetics (e.g., Epinephrine) · Mutual antagonism · moderate
- Diltiazem · Additive negative inotropic and chronotropic effects, increasing risk of severe bradycardia and hypotension. · major
監測
- Blood Pressure
- ECG
- Heart Rate
- Continuous Electrocardiogram (ECG)
- Direct or indirect blood pressure
- Heart rate and rhythm
- Clinical signs of heart failure
過量
The IV LD50 in dogs is approximately 32 mg/kg. * **2 mg/kg/min for 1 hour:** No adverse effects. * **3 mg/kg/min for 1 hour:** Produced ataxia and salivation. * **4 mg/kg/min for 1 hour:** Caused muscular rigidity, tremors, seizures, ptosis, vomiting, hyperpnea, vocalizations, and prostration. **Management:** These effects all resolved within 90 minutes of the end of infusion. Because of the short duration of action of the drug, discontinuation or dosage reduction may be all that is required; otherwise, symptomatic and supportive treatment may be initiated.
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