チオペンタールナトリウム
Thiopental Sodium
Thiopental sodium
別名: Pentothal · Anesthal · Bensulf · Farmotal · Hipnopento · Inductal · Intraval · Nesdonal · Pensodital · Sandothal · Sodipental · Thionembutal · Thiopentax · Tiobarbital · Trapanal · Thiopentone sodium · natrium isopentylaethylthiobarbituricum · penthiobarbital sodique · thiomebumalnatrium cum natrii carbonate · thiopentalum natricum · thiopentobarbitalum solubile · tiopentol sodico
VetSheet 獣医チームが監修更新日 2026年4月5日エビデンスに基づく獣医学リファレンス
用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。
動物種別用量
🌎 NA — North America🌍 EU — Europe
犬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Anesthesia | 13.2-26.4 mg/kg | IV | once | depending on duration of anesthesia required | 🌎 NA |
| Brief anesthesia (7-10 minutes) | 15-17 mg/kg | IV | once | — | 🌎 NA |
| Moderate anesthesia (10-15 minutes) | 18-22 mg/kg | IV | once | — | 🌎 NA |
| Longer anesthesia (15-25 minutes) | 22-29 mg/kg | IV | once | — | 🌎 NA |
| Anesthesia (unpremedicated) | 22 mg/kg | IV | once | — | 🌎 NA |
| Anesthesia (after tranquilization) | 15.4 mg/kg | IV | once | — | 🌎 NA |
| Anesthesia (after narcotic premedication) | 11 mg/kg | IV | once | — | 🌎 NA |
| Anesthesia induction | 12-15 mg/kg | IV | once | — | 🌎 NA |
- Anesthesia induction: One-third administered rapidly, additional amount to effect
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Anesthesia | 13.2-26.4 mg/kg | IV | once | depending on duration of anesthesia required | 🌎 NA |
| Anesthesia (unpremedicated) | 22 mg/kg | IV | once | — | 🌎 NA |
| Anesthesia (after tranquilization) | 15.4 mg/kg | IV | once | — | 🌎 NA |
| Anesthesia (after narcotic premedication) | 11 mg/kg | IV | once | — | 🌎 NA |
| Anesthesia induction | 12-15 mg/kg | IV | once | — | 🌎 NA |
- Anesthesia induction: One-third administered rapidly, additional amount to effect
小型哺乳類
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Anesthesia (Rabbits) | 15-30 mg/kg | IV | to effect | — | 🌎 NA |
| Anesthesia (Rabbits) | 10-12 mg/kg | IV | to effect | — | 🌎 NA |
| Chemical restraint (Mice) | 50 mg/kg | IP | once | — | 🌎 NA |
| Chemical restraint (Rats) | 40 mg/kg | IP | once | — | 🌎 NA |
| Chemical restraint (Hamsters/Gerbils) | 30-40 mg/kg | IP | once | — | 🌎 NA |
| Chemical restraint (Guinea pig) | 15-30 mg/kg | IV | once | — | 🌎 NA |
| Chemical restraint (Rabbits) | 15-30 mg/kg | IV | once | — | 🌎 NA |
馬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Anesthesia (with preanesthetic tranquilization) | 6-12 mg/kg (average 8.25 mg/kg) | IV | once | — | 🌎 NA |
| Anesthesia (without preanesthetic tranquilization) | 8.8-15.4 mg/kg (average 9.9-11 mg/kg) | IV | once | — | 🌎 NA |
| Anesthesia (after xylazine or acepromazine) | 1 gram per 90 kg body weight as a 10% solution | IV | once | — | 🌎 NA |
| Anesthesia (after sedation and guaifenesin) | 5.5 mg/kg | IV | once | — | 🌎 NA |
| Anesthesia (after tranquilization) | 8.8-11 mg/kg | IV | once | — | 🌎 NA |
- Anesthesia (after xylazine or acepromazine): Given evenly over 20 seconds, 15 minutes after premedication
牛
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Anesthesia | 8.14-15.4 mg/kg | IV | once | — | 🌎 NA |
| Deep surgical anesthesia (unweaned calves fasted 6-12h) | no more than 6.6 mg/kg | IV | once | — | 🌎 NA |
| Anesthesia (calves under 2 weeks of age) | 15-22 mg/kg | IV | once | 10-12 minutes | 🌎 NA |
| Anesthesia (after sedation and guaifenesin) | 5.5 mg/kg | IV | once | — | 🌎 NA |
| Anesthesia (after tranquilization) | 8.8-11 mg/kg | IV | once | — | 🌎 NA |
- Anesthesia (calves under 2 weeks of age): Administer slowly until complete muscular relaxation
豚
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Anesthesia | 5.5-11 mg/kg | IV | once | — | 🌎 NA |
| Anesthesia (swine weighing 5-50 kg) | 10-11 mg/kg | IV | once | — | 🌎 NA |
羊
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Anesthesia | 9.9-15 mg/kg | IV | once | depending on depth required | 🌎 NA |
ヤギ
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Anesthesia | 20-22 mg/kg | IV | once | — | 🌎 NA |
- Anesthesia: Given after atropine (0.7 mg/kg) IM
用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。
概要
チオペンタールナトリウムは、主に全身麻酔の導入や極めて短時間の処置における単独麻酔薬として使用される超短時間作用型チオバルビツール酸系薬剤です。
臨床上のポイント：
- 再分布の動態： 作用時間が短い（10〜30分）のは、急速な代謝によるものではなく、血流の豊富な中枢神経系から筋肉や脂肪組織への急速な再分布によるものです。
- サイトハウンドの感受性： グレイハウンドなどのサイトハウンドは、代謝の違いや体脂肪の少なさから回復が遅延します。プロポフォール、アルファキサロン、メトヘキシタールなどの代替導入薬が一般的に推奨されます。
- 組織毒性： チオペンタール溶液は強アルカリ性（pH > 10）です。血管外漏出は重度の組織刺激と壊死を引き起こします。 確実な静脈カテーテルを介して投与する必要があります。
- 不整脈誘発性： カテコールアミンに対する心筋の感受性を高め、犬では一過性の心室性二段脈をよく引き起こします。
作用機序
Thiopental is a highly lipid-soluble thiobarbiturate.
- Mechanism: It binds to the GABA_A receptor complex in the central nervous system.
- Pathway: Binding → increases the duration of chloride ion channel opening → enhances chloride influx → hyperpolarization of the postsynaptic neuronal membrane → profound CNS depression, hypnosis, and anesthesia.
- Due to its high lipid solubility, it rapidly crosses the blood-brain barrier, resulting in anesthesia within 15-30 seconds of IV injection.
安全性・警告
禁忌
- Absence of suitable veins for IV administration (Absolute)
- History of hypersensitivity to barbiturates (Absolute)
- Status asthmaticus (Absolute)
- Preexisting leukopenia in horses
- Use with extreme caution or avoid in greyhounds and other sight hounds
- Relative: Severe cardiovascular disease, ventricular arrhythmias, shock, increased intracranial pressure, myasthenia gravis, severe hepatic disease
有害事象
- Ventricular bigeminy (dogs)
- Apnea (especially in cats)
- Arterial hypotension
- Excitement and severe ataxia during recovery (horses, if used alone)
- Transient leukopenia and hyperglycemia (horses)
- Vascular dilatation and hypoglycemia (with rapid IV administration)
- Severe tissue necrosis (if administered perivascularly)
- Prolonged recovery with repeated doses
注意事項
WARNING: Thiopental is highly alkaline. Extravasation and intra-arterial injections must be strictly avoided to prevent severe tissue necrosis and CNS toxicity.
- Sight Hounds: Greyhounds metabolize thiobarbiturates much more slowly; prolonged recoveries are common. Consider alternatives.
- Administration: Give strictly to effect. Repeated doses accumulate and significantly prolong recovery.
- Dilution: Do not use concentrations less than 2% in sterile water as they may cause hemolysis.
- Pregnancy: Readily crosses the placental barrier; use with caution (FDA Category C).
医薬品相互作用
IV clonidine prior to induction may reduce thiopental dosage requirements by up to 37%
May enhance respiratory and CNS depressant effects
Potential for hypotension
Ventricular fibrillatory effects may be potentiated when used with thiobarbiturates and halothane
Given prior to induction may reduce thiopental dosage requirements
May potentiate hypnotic effects
Given prior to induction may reduce thiopental dosage requirements
May potentiate thiopental effects; hypotension possible
May displace thiopental from plasma proteins
Thiopental and sulfas may displace one another from plasma proteins
監視
- Level of hypnosis/anesthesia
- Respiratory status (rate, depth, apnea)
- Cardiac status (heart rate, rhythm, blood pressure)
薬物動態
半減期
吸収
Following IV injection, hypnosis and anesthesia occur within one minute (usually 15-30 seconds).
分布
Rapidly enters the CNS due to high lipid solubility, then redistributes to muscle and adipose tissue.
代謝
Metabolized by the hepatic microsomal system into several metabolites.
消失
Very little of the drug is excreted unchanged in the urine. Elimination half-life in dogs is approximately 7 hours (3-4 hours in sheep).
過剰投与
Treatment of thiobarbiturate overdosage consists of:
- Respiratory Support: Provide oxygen (O2) and mechanical ventilation.
- Cardiovascular Support: Provide IV fluids and supportive care.
Note: Do NOT use catecholamines (e.g., epinephrine) as they may induce fatal ventricular arrhythmias in the presence of thiobarbiturates.
製品
製剤
- Powder for injection: 2% (20 mg/mL)
- Powder for injection: 2.5% (25 mg/mL)
動物用医薬品
- None presently being marketed in USA
ヒト用医薬品
- Thiopental Sodium Powder for Injection: 2% (20 mg/mL)
- Thiopental Sodium Powder for Injection: 2.5% (25 mg/mL)
規制ステータス
規制データなし: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Dry form is stable indefinitely. Reconstitute only with sterile water, normal saline, or D5W. Concentrations <2% in sterile water should not be used (may cause hemolysis). Reconstituted solutions are stable for 3 days at room temperature and 7 days refrigerated; however, use within 24 hours is recommended as no preservative is present. Do not administer if a precipitate is visible.
飼主向け情報
チオペンタールは、動物病院において獣医療従事者のみが使用する注射用麻酔薬です。
- モニタリング： 麻酔中、ペットの心拍数、呼吸、血圧などは厳密に監視されます。
- 回復： 麻酔からの回復には数時間かかる場合があります。特定の犬種（特にグレイハウンドなどのサイトハウンド）では、回復時間が著しく長くなることがあります。
- 麻酔後のケア： ペットが帰宅した後の食事や運動については、獣医師の指示に従ってください。
VetSheet医薬品リファレンスは獣医専門家の臨床意思決定支援を目的としており、専門的判断または製造業者の最新医薬品情報の代替にはなりません。