戊巴比妥
Pentobarbital
Pentobarbital sodium
別名: Nembutal · Dolethal · Euthanimal · Euthasal · Euthatal · Euthoxin · Lethobarb · Pentoject · aethaminalum · mebubarbital · mebumal · pentobarbitalum · pentobarbitone · Pentobarbital 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
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僅供證據參考，不會自動計算
Crocodilians
TABLE 127.5. Agent: Pentobarbital. Dosage: 7.5–15 mg/kg ICe, or 8 mg/kg IM18,229. Species/Comments: Crocodilians.
僅供證據參考，不會自動計算
Snakes/induction, 30–60 min; duration, ≥ 2 hr; prolonged recovery (risk of occasional fatalities); venomous snakes require twice as much as nonvenomous snakes;18 avoid use in lizards
TABLE 127.5. Agent: Pentobarbital. Dosage: 15–30 mg/kg ICe229. Species/Comments: Snakes/induction, 30–60 min; duration, ≥ 2 hr; prolonged recovery (risk of occasional fatalities); venomous snakes require twice as much as nonvenomous snakes;18 avoid use in lizards.
僅供證據參考，不會自動計算
Chelonians
TABLE 127.5. Agent: Pentobarbital. Dosage: 10–18 mg/kg ICe229. Species/Comments: Chelonians.
僅供證據參考，不會自動計算
Rarely used as an anesthetic agent in reptiles
TABLE 127.5. Agent: Pentobarbital. Dosage: —. Species/Comments: Rarely used as an anesthetic agent in reptiles.
劑量為合格獸醫專業人員的臨床參考。請務必對照最新仿單及個別病患確認。
概覽
戊巴比妥 (Pentobarbital) 是一種短效的氧巴比妥類藥物，在獸醫學中主要用於全身麻醉、化學保定以及難治性癲癇重積狀態的處理。
雖然過去常作為全身麻醉劑，但由於其治療指數狹窄且具有強烈的心肺抑制作用，目前已大多被更安全、更易滴定的藥物（如丙泊酚 Propofol 或阿法沙龍 Alfaxalone）所取代。
臨床要點：
- 癲癇重積狀態： 戊巴比妥常被用於誘導難治性癲癇患者進入「巴比妥昏迷」狀態。然而，在標準劑量下，它主要作為全身麻醉劑，缺乏真正的抗癲癇特性；它能停止癲癇的肢體表現，但可能無法阻止大腦內潛在的異常放電。
- 呼吸支持： 因嚴重癲癇而接受戊巴比妥治療的病患，通常會出現嚴重的呼吸抑制，需要機械通氣和加護病房監測。
- 安樂死： 在極高劑量下，戊巴比妥是大多數獸醫安樂死溶液的主要活性成分。
- 酵素誘導： 長期使用會強烈誘導肝臟細胞色素 P450 酵素，加速許多併用藥物的代謝。
作用機轉
Pentobarbital exerts its profound central nervous system (CNS) depressant effects by interacting with the inhibitory neurotransmitter system.
- GABA_A Receptor Modulation: Binds to the barbiturate site on the GABA_A receptor → increases the duration of chloride channel opening → enhances chloride influx → hyperpolarization of the postsynaptic neuronal membrane.
- Glutamate Inhibition: At higher anesthetic doses, it also depresses the actions of the excitatory neurotransmitter glutamate via AMPA receptors.
- Result: Dose-dependent CNS depression ranging from mild sedation to general anesthesia, coma, and fatal respiratory depression.
安全性與警告
禁忌症
- Severe hepatic impairment
- Severe respiratory depression or airway obstruction
- Porphyria
- Hypovolemia or severe cardiovascular instability (relative contraindication)
- Intramuscular (IM) administration (painful and slow to act)
- Use of euthanasia-specific solutions for seizure control or anesthesia
不良反應
- Profound respiratory depression (apnea)
- Depression of myocardial metabolism
- Vasodilation and decreased venous return
- Hypotension and decreased cardiac perfusion
- Poikilothermia (hypothermia)
- Decreased urinary output
- Seizure-like movements or excitement during recovery from anesthesia
- Excitement and injury during induction/recovery in large animals (especially horses)
- Narcotic excitement (if not premedicated)
- Agonal gasping (reflexive, not a sign of pain)
- Muscle twitching
- Vocalization (rare, usually associated with excitement phase)
注意事項
Cardiopulmonary Depression: Pentobarbital causes dose-dependent respiratory and cardiovascular depression. Patients in a 'barbiturate coma' commonly require mechanical ventilation and intensive care support (e.g., saline infusion and dopamine to manage hypotension).
Individual Variation: There is tremendous individual variation in response when used at standard safe doses. Always titrate to effect.
Laboratory Interference: Barbiturates may cause increased retention of bromosulfophthalein (BSP) and give falsely elevated results. Do not administer within 24 hours before BSP retention tests.
- Equine Use: Generally not considered an ideal agent for adult horses due to the possible development of excitement and injury when the animal is 'knocked down'.
- Tissue Irritation: Highly alkaline (pH 9-10.5); perivascular injection can cause severe tissue necrosis.
藥物交互作用
Decreased effect by lowering serum concentration (due to hepatic enzyme induction)
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Decreased effect (may persist for weeks after barbiturate is discontinued)
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Decreased effect by lowering serum concentration
Increase the CNS depressant effect of pentobarbital
Increase the CNS depressant effect of pentobarbital
監測
- Levels of consciousness and/or seizure control
- Respiratory rate, rhythm, and depth (capnography and pulse oximetry highly recommended)
- Cardiac signs (heart rate, blood pressure, ECG)
- Body temperature (monitor for poikilothermia)
- Routine blood counts and liver function tests (if used chronically)
- Absence of heartbeat (auscultation)
- Absence of respiration
- Loss of corneal reflex
- Pupillary dilation
藥物動力學
半衰期
吸收
Rapidly absorbed following oral or intraperitoneal administration.
分佈
Highly lipid soluble; rapidly crosses the blood-brain barrier to exert CNS effects. It subsequently redistributes from the brain to highly perfused tissues, and eventually to muscle and fat, which terminates its initial anesthetic effect.
代謝
Extensively metabolized in the liver via cytochrome P450 enzymes. Chronic administration induces these enzymes, accelerating its own metabolism and that of other drugs.
排除
Metabolites are primarily excreted by the kidneys.
過量
Overdose of pentobarbital leads to profound central nervous system depression, progressing rapidly to coma, severe respiratory depression (apnea), cardiovascular collapse, and death.
- Treatment: There is no specific reversal agent for barbiturates. Treatment is entirely supportive.
- Interventions: Immediate intubation and mechanical ventilation are required. Intravenous fluids and vasopressors (e.g., dopamine) should be administered to support blood pressure and cardiac output. Maintain body temperature to prevent severe hypothermia.
可用產品
劑型
- Injection (50 mg/mL)
- Suppositories
- Injectable: 200 mg/ml non-sterile aqueous solution
- Injectable: 400 mg/ml non-sterile aqueous solution
- Injectable: 500 mg/ml non-sterile aqueous solution
獸醫用
- Dolethal 200 mg/ml solution for injection
- Euthanimal 200 mg/ml / 400 mg/ml solution for injection
- Euthasal 400 mg/ml solution for injection
- Euthatal 200 mg/ml solution for injection
- Euthoxin 500 mg/ml solution for injection
- Lethobarb 200 mg/ml solution for injection
- Pentoject 200 mg/ml solution for injection
人用標示
- Pentobarbital Sodium Injection: 50 mg/mL in 2 mL Tubex; generic; (WyethAyerst); (Rx, C-II)
各地核准狀態
Carcasses must not enter the food chain.
POM-V CD SCHEDULE 3. Safe custody requirements apply.
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儲存與穩定性
The injectable product should be stored at room temperature; suppositories should be kept refrigerated. The aqueous solution is not very stable and should not be used if it contains a precipitate. Because precipitates may occur, pentobarbital sodium should not be added to acidic solutions.
飼主須知
本藥物是一種強效的鎮靜劑和麻醉劑。
- 醫院內使用： 幾乎完全在獸醫院內由專業人員密切監督下使用，通常是在加護病房環境中。
- 居家使用： 如果配發口服劑型供居家使用，嚴格遵守獸醫師的劑量指示至關重要。過量使用可能致命。
- 安全性： 請將本藥物保存在安全、防兒童開啟的容器中，並完全放置在兒童和其他寵物接觸不到的地方。這是一種受到嚴格管制的藥物。
VetSheet 藥物參考供合格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商最新仿單。