依託咪酯
依託咪酯是一種短效的注射型非巴比妥類麻醉誘導劑。在獸醫學中，它以**心血管穩定性**著稱，對於患有心臟功能障礙、頭部外傷或重症的病患，它是硫噴妥鈉 (thiopental) 或異丙酚 (propofol) 的優良替代品。 **臨床重點：** * **血流動力學穩定：** 對心率和血壓的影響極小，非常適合心臟病或休克病患。 * **神經學益處：** 可降低腦血流、腦耗氧量及顱內壓，對頭部外傷病患有益。 * **內分泌影響：** 會抑制皮質醇 (cortisol) 的產生，重症病患可能需要補充皮質類固醇。 * **無鎮痛作用：** 僅提供催眠與失憶效果，必須合併使用適當的鎮痛藥物。
作用機制: While the exact mechanism is not definitively proven, etomidate is known to act primarily as a positive allosteric modulator and direct agonist at the **GABA_A receptor** in the central nervous system. * **Mechanism:** Binds to a specific site on the GABA_A receptor → enhances the affinity of the inhibitory neurotransmitter GABA for the receptor → increases transmembrane chloride conductance → hyperpolarizes the postsynaptic neuron → profound CNS depression and hypnosis. * **Endocrine Mechanism:** Directly inhibits **11-β-hydroxylase** (and to a lesser extent 17-α-hydroxylase) in the adrenal cortex → blocks the conversion of 11-deoxycortisol to cortisol → transient adrenal insufficiency.
各物種劑量
- As an induction agent · 1 mg/kg IV plus diazepam 0.5 mg/kg IV · IV · Once
- As an induction agent · 1-2 mg/kg rapidly IV · IV · Once
- As an induction agent · 0.5-2 mg/kg IV · IV · Once · Pre-medication is highly recommended to reduce incidence of side effects (myoclonus, vomiting). May be given with a benzodiazepine. Administration of a physiologic dose of dexamethasone or another short-acting glucocorticoid prior to etomidate is suggested.
- As an induction agent in the cardiovascular unstable patient · 1-2 mg/kg IV after diazepam (0.5 mg/kg IV) · IV · Once
- As an induction agent in the cardiovascular unstable patient (Rabbits) · 1-2 mg/kg IV after diazepam (0.5 mg/kg IV) · IV · Once
- As an induction agent · 1 mg/kg IV plus diazepam 0.5 mg/kg IV · IV · Once
- As an induction agent · 1-2 mg/kg rapidly IV · IV · Once
- As an induction agent · 0.5-2 mg/kg IV · IV · Once · Pre-medication is highly recommended to reduce incidence of side effects (myoclonus, vomiting). May be given with a benzodiazepine. Administration of a physiologic dose of dexamethasone or another short-acting glucocorticoid prior to etomidate is suggested.
給藥途徑
禁忌症
- Known hypersensitivity to etomidate
- Maintenance of anesthesia (due to cumulative adrenal suppression)
- Use as a sole agent for painful procedures (lacks analgesia)
不良反應
- Pain at intravenous injection site
- Myoclonus (skeletal muscle movements)
- Vomiting and post-operative retching
- Eye movements
- Hemolysis (due to propylene glycol carrier)
- Brief hypoventilation and decreased arterial blood pressure
- Apnea, laryngospasm, or hiccups (reported in humans)
藥物相互作用
- CNS/Respiratory Depressants (e.g., barbiturates, opiates, anesthetics) · Additive pharmacological effects; can increase CNS or respiratory depression.
- Verapamil · Associated with potentiating the anesthetic and respiratory depressant effects of etomidate.
監測
- Level of consciousness
- Respiration rate and depth
- Cardiovascular function (blood pressure, heart rate, ECG)
過量
Acute overdoses would be expected to cause enhanced pharmacologic effects of the drug, including profound CNS and respiratory depression. Treatment is supportive (e.g., mechanical ventilation, cardiovascular support) until the effects of the medication are diminished.
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。