エトミダート
エトミダートは短時間作用型の注射用非バルビツール酸系麻酔導入薬です。獣医療においては**心血管系の安定性**が高く評価されており、心機能障害、頭部外傷、または重篤な状態にある患者において、チオペンタールやプロポフォールの優れた代替薬となります。 **臨床上の重要ポイント：** * **血行動態の安定性：** 心拍数や血圧への影響が最小限であるため、心疾患やショック状態の患者に最適です。 * **神経学的利点：** 脳血流、脳酸素消費量、頭蓋内圧を低下させるため、頭部外傷患者に有益です。 * **内分泌への影響：** コルチゾール産生を抑制するため、重篤な患者ではコルチコステロイドの補充が必要になる場合があります。 * **鎮痛作用の欠如：** 催眠および健忘作用はありますが鎮痛作用はないため、適切な鎮痛薬の併用が必須です。
作用機序: 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.
動物種別の用量
- 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.
投与経路
禁忌
- Known hypersensitivity to etomidate
- Maintenance of anesthesia (due to cumulative adrenal suppression)
- Use as a sole agent for painful procedures (lacks analgesia)
有害事象
- 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)
薬物相互作用
- 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.
モニタリング
- Level of consciousness
- Respiration rate and depth
- Cardiovascular function (blood pressure, heart rate, ECG)
過量投与
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 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。