VetSheet

美索比妥

Methohexital

Methohexital sodium

超短效巴比妥類麻醉劑IV狗貓

別名: Brevital · Brevimytal · Brietal · compound 25398 · enallynymalnatrium · methohexitone sodium

由 VetSheet 獸醫團隊審訂更新於 2026年4月5日本內容以實證獸醫文獻為本

經審核的 v13 劑量證據

經審核的非計算證據
經審核的非計算證據 (3)

只供證據參考，不會自動計算

Recovery time of red-sided garter snakes at 21°C (70°F), 125 min; 26°C (79°F), 86 min; 31°C (88°F), 64 min; thinner snakes had longer recovery times; if within 5 wk of parturition, mean recovery time 2 × as long as nongravid; time postfeeding had no effect at 1, 3, 10 days266

TABLE 127.5. Agent: Methohexital (Brevital, Lilly). Dosage: —. Species/Comments: Recovery time of red-sided garter snakes at 21°C (70°F), 125 min; 26°C (79°F), 86 min; 31°C (88°F), 64 min; thinner snakes had longer recovery times; if within 5 wk of parturition, mean recovery time 2 × as long as nongravid; time postfeeding had no effect at 1, 3, 10 days266.

高風險須由已驗證獸醫確認drug_regimen方案年份 2019審核 dose-audit-mader-reviewed-v1

只供證據參考，不會自動計算

Most species/induction, 5–30 min; recovery, 1–5 hr; use at 0.125%–0.5% concentration; much species variability; decrease dose 20%–30% for young animals; avoid use in debilitated animals

TABLE 127.5. Agent: Methohexital (Brevital, Lilly). Dosage: 5–20 mg/kg SC,19 IV89. Species/Comments: Most species/induction, 5–30 min; recovery, 1–5 hr; use at 0.125%–0.5% concentration; much species variability; decrease dose 20%–30% for young animals; avoid use in debilitated animals.

IVSC
高風險須由已驗證獸醫確認drug_regimen方案年份 2019審核 dose-audit-mader-reviewed-v1

只供證據參考，不會自動計算

Colubrids/induction, ≥ 22 min; recovery, 2–5 hr; does not produce soft-tissue irritation seen with other barbiturates; may need to adjust dosage in obese snakes

TABLE 127.5. Agent: Methohexital (Brevital, Lilly). Dosage: 9–10 mg/kg SC,243 ICe. Species/Comments: Colubrids/induction, ≥ 22 min; recovery, 2–5 hr; does not produce soft-tissue irritation seen with other barbiturates; may need to adjust dosage in obese snakes.

ICeSC
高風險須由已驗證獸醫確認drug_regimen方案年份 2019審核 dose-audit-mader-reviewed-v1

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。

正在為病患診症？VetSheet 的 AI 會把藥物、劑量與療程直接寫入結構化診症筆記。了解 VetSheet 如何運作

概覽

美索比妥（Methohexital）是一種超短效的甲基氧巴比妥類麻醉劑。雖然在現代獸醫學中已很大程度上被異丙酚（Propofol）取代，但它在特定情況下仍具實用性，特別是對於​視覺獵犬​（如靈緹犬），因為其作用的終止依賴於快速的肝臟代謝，而非重新分佈到脂肪組織。它也有利於胃部充滿食物的病患進行快速插管，以防止嘔吐物吸入。

​臨床要點​：

  • 本藥不具鎮痛或肌肉鬆弛作用。
  • 對組織具強烈刺激性；若發生血管外滲漏會導致嚴重的局部組織壞死。
  • 其效力約為硫噴妥（Thiopental）的兩倍，但作用時間僅為其一半。

作用機制

Methohexital produces dose-dependent CNS depression by depressing the reticular activating system in the brainstem.

  • Mechanism: Binds to the GABA_A receptor complex → prolongs the opening of chloride channels → increases intracellular chloride influx → cellular hyperpolarization → profound inhibition of neuronal firing.
  • Termination of Effect: Unlike thiobarbiturates, methohexital is rapidly metabolized by the liver and does not depend on redistribution to fat to reverse its effects.

安全性與警告

禁忌症

  • Absence of suitable veins for IV administration
  • History of hypersensitivity reactions to barbiturates
  • Status asthmaticus
  • Cattle (due to unpredictable effects)

不良反應

  • Apnea
  • Hypotension
  • Muscle tremors
  • Seizures during recovery
  • Rough recoveries (especially in dogs)
  • Profound respiratory depression
  • Tissue necrosis (if extravasated)

注意事項

WARNING: Strictly for IV use. Perivascular extravasation causes severe tissue necrosis. Extravasation injuries can be treated with multiple infiltrates of sterile normal saline and lidocaine for pain.

  • Relative Contraindications: Seizure-prone animals, severe cardiovascular disease, preexisting ventricular arrhythmias, shock, increased intracranial pressure, myasthenia gravis, asthma, and conditions with prolonged hypnotic effects (e.g., severe hepatic disease, myxedema, severe anemia).
  • Species Warnings: NOT recommended for use in cattle due to unpredictable effects.
  • Administration: Repeated dosing or IV infusions are not recommended as recovery times can be significantly prolonged and increase the risk for complications.

藥物相互作用

CNS Depressants (e.g., alpha2-agonists, opioids)

Additive CNS and respiratory depression; premedication is usually preferred to reduce methohexital dosage required for inductions and to decrease rough recoveries.

監測

  • Plane of anesthesia
  • Respiratory rate and depth
  • Cardiac rate, rhythm, and blood pressure
  • CNS stimulation (seizures) upon recovery

藥物動力學

半衰期

狗3-5 hours (elimination)

吸收

Rapid onset of anesthesia (15-60 seconds) after IV injection.

分佈

Distribution half-life is 5-6 minutes. Not dependent on redistribution to fat to reverse its effects.

代謝

Rapidly metabolized by the liver.

排除

No drug is detectable in the body 24 hours after administration. Recovery times in small animals average 30 minutes.

過量

Narrow Safety Margin: The lethal dose may only be 2-3 times the anesthetic dose.

  • Clinical Signs: Profound respiratory depression, apnea, hypotension, and cardiovascular collapse.
  • Treatment: Requires immediate mechanical ventilation and cardiovascular support. Postoperative seizures have been reported and can be treated with IV diazepam.

可用產品

劑型

  • Powder for injection

人用標示

  • Methohexital Sodium Powder for Injection: 500 mg & 2.5 grams in 50 mL multiple dose vials

各地核准狀態

暫無法規資料: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU

儲存與穩定性

Store powder at room temperature (<25°C). Reconstitute preferably with sterile water for injection (D5W or 0.9% NaCl may be used for 0.2% concentrations). Do NOT use solutions with bacteriostatic agents. Incompatible with silicone (avoid silicone-treated rubber stoppers/syringes). Do NOT mix with acidic drugs (e.g., atropine, succinylcholine).

飼主須知

美索比妥是一種速效麻醉劑，僅在醫院環境中使用，用於手術或短暫處置前引導寵物進入睡眠狀態。

  • ​作用迅速​：它在幾秒鐘內即可生效，使獸醫團隊能快速確保寵物的呼吸道安全。
  • ​恢復期​：有些寵物（尤其是狗）在醒來時可能會經歷「不平穩的恢復」（如顫抖、興奮或發聲）。獸醫團隊會密切監測，並可能使用其他藥物來平緩此過程。
  • ​安全性​：在藥物作用期間，將持續監測寵物的心跳、呼吸和血壓。

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。