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クロルプロマジン

Chlorpromazine

Chlorpromazine Hydrochloride

フェノチアジン系鎮静薬/制吐薬POIMIVSC犬猫牛豚羊ヤギ

別名: Thorazine · aminazine · chlorpromazini hydrochloridum

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

0.5 mg/kg IV, IM or SC three to four times dailyIV/IM/SC· q6-8h
— 🐕

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
As an antiemetic0.5 mg/kg IV, IM or SC three to four times dailyIV/IM/SCq6-8h—🌎 NA
As an antiemetic0.2-0.4 mg/kg SC, IM q8hSC/IMq8h—🌎 NA
As an antiemetic4-8 mg (total dose; do not exceed 0.5 mg/kg) per dog PO q12hPOq12h—🌎 NA
As a muscle relaxant during tetanus2 mg/kg IM twice dailyIMq12h—🌎 NA

猫

適応用量経路頻度期間地域
As an antiemetic0.5 mg/kg IV, IM or SC three to four times dailyIV/IM/SCq6-8h—🌎 NA
As an antiemetic2 mg (total dose) per cat PO q12hPOq12h—🌎 NA
As a preanestheticup to 1.1 mg/kg IM 1-1.5 hours prior to surgeryIMOnce—🌎 NA

牛

適応用量経路頻度期間地域
Premedication for cattle undergoing standing proceduresUp to 1 mg/kg IMIMOnce—🌎 NA
  • Premedication for cattle undergoing standing procedures: May cause regurgitation if animal undergoes general anesthesia

豚

適応用量経路頻度期間地域
Premedication1 mg/kg IMIMOnce—🌎 NA
Premedication0.55-3.3 mg/kg IV; 2-4 mg/kg IMIV/IMOnce—🌎 NA
Restraint1.1 mg/kg IMIMOnce—🌎 NA
Prior to barbiturate anesthesia2-4 mg/kg IMIMOnce—🌎 NA
  • Restraint: Effects are at peak in 45-60 minutes

羊

適応用量経路頻度期間地域
General use0.55-4.4 mg/kg IV, 2.2-6.6 mg/kg IMIV/IMOnce—🌎 NA

ヤギ

適応用量経路頻度期間地域
General use0.55-4.4 mg/kg IV, 2.2-6.6 mg/kg IMIV/IMOnce—🌎 NA
General use2-3.5 mg/kg IV q5-6hIVq5-6h—🌎 NA

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。

診察中ですか？VetSheet の AI が薬剤・用量・投与期間を構造化された診察記録に直接記入します。VetSheet の仕組みを見る

概要

クロルプロマジンはプロトタイプのフェノチアジン系誘導体であり、歴史的に獣医学において神経遮断薬および鎮静薬として使用されてきましたが、現在ではより強力で作用時間の短いアセプロマジンに大部分が取って代わられています。

現在では主に小動物の​制吐作用​、特に猫の乗り物酔いの管理に利用されています。

​臨床上の重要なポイント:​

  • 犬（猫ではない）におけるアポモルヒネ誘発性嘔吐、およびモルヒネ誘発性嘔吐を効果的に抑制します。
  • 硫酸銅やジギタリス配糖体による嘔吐は抑制しません。
  • ​鎮痛作用はほとんどありません​。痛みを伴う状態には適切な鎮痛薬を投与する必要があります。
  • 逆説的な興奮や運動失調を引き起こすため、馬への使用は一般的に禁忌です。
  • 著しい血管拡張と低血圧を引き起こす可能性があります。投与前に患者に十分な水分補給を行う必要があります。

作用機序

Chlorpromazine acts primarily as a dopamine (D2) receptor antagonist in the central nervous system.

  • ​Antiemetic effect:​ Blocks D2 receptors in the Chemoreceptor Trigger Zone (CRTZ) of the medulla → inhibits emetic signaling to the vomiting center.
  • ​Sedative effect:​ Antagonizes central ​histamine (H1)​, alpha-1 adrenergic, and dopamine receptors → depresses the reticular activating system.
  • ​Cardiovascular effect:​ Peripheral alpha-1 adrenergic blockade → vasodilation and potential hypotension.
  • Also possesses weak anticholinergic (muscarinic M1 blockade) and antiserotonergic properties.

安全性・警告

禁忌

  • Horses (generally not recommended due to severe ataxia and panic reactions)
  • Rabbits (IM injection causes severe muscle discomfort and swelling)
  • Hypovolemia or shock
  • Tetanus or strychnine intoxication (due to extrapyramidal effects)

有害事象

  • Hypotension
  • CNS stimulation (paradoxical)
  • Bradycardia or tachycardia
  • Extrapyramidal signs in cats (tremors, shivering, rigidity, loss of righting reflexes)
  • Lethargy
  • Diarrhea
  • Loss of anal sphincter tone
  • Ataxia, excitation, and panic reactions in horses
  • Hypothermia or hyperthermia

注意事項

​Important:​ Intravenous injections must be diluted with saline to concentrations of no more than 1 mg/mL and administered slowly. Do not inject into arteries.

  • ​MDR1 Mutation:​ Dogs with MDR1 mutations (Collies, Australian Shepherds, etc.) may develop pronounced and prolonged sedation. Reduce initial doses by 25% in suspect patients.
  • ​Aggressive Dogs:​ Use cautiously as a restraining agent; it may make the animal more prone to startle and react to noises or sensory inputs.
  • ​Debilitated Patients:​ Use cautiously and in smaller doses in animals with hepatic dysfunction, cardiac disease, or general debilitation.
  • ​Anesthesia:​ Animals may require lower dosages of general anesthetics following phenothiazines.

医薬品相互作用

Acetaminophen

Possible increased risk for hypothermia

Antacids

May cause reduced GI absorption of oral phenothiazines

Antidiarrheal mixtures (e.g., kaolin/pectin, bismuth subsalicylate)

May cause reduced GI absorption of oral phenothiazines

CNS Depressant Agents (barbiturates, narcotics, anesthetics)

May cause additive CNS depression

Dipyrone

May cause serious hypothermia

Epinephrine

Phenothiazines block alpha-adrenergic receptors; concomitant epinephrine can lead to unopposed beta-activity causing vasodilation and increased cardiac rate (epinephrine reversal)

Opiates

May enhance hypotensive effects; chlorpromazine dosages may need reduction

Organophosphate Agents

Effects may be potentiated; do not give phenothiazines within one month of worming with these agents

Paraquat

Toxicity may be increased by chlorpromazine

Phenytoin

Metabolism may be decreased if given concurrently

Physostigmine

Toxicity may be enhanced by chlorpromazine

Procaine

Activity may be enhanced by phenothiazines

Propranolol

Increased blood levels of both drugs may result

Quinidine

May cause additive cardiac depression

監視

  • Cardiac rate, rhythm, and blood pressure (if indicated and possible)
  • Degree of tranquilization and anti-emetic activity
  • Body temperature (especially in extreme ambient temperatures)

薬物動態

吸収

Absorbed rapidly after oral administration, but undergoes extensive first pass metabolism in the liver. Well absorbed after IM injection, but onset of action is slower than IV.

分布

Distributed throughout the body; brain concentrations are higher than plasma. Approximately 95% is bound to plasma proteins (primarily albumin).

代謝

Extensively metabolized principally in the liver and kidneys.

消失

Little specific information is available regarding its excretion in dogs and cats.

過剰投与

Small overdoses typically cause somnolence. Larger overdoses can cause serious effects including coma, agitation/seizures, ECG changes/arrhythmias, hypotension, and extrapyramidal effects.

  • ​Treatment:​ Most overdoses are managed with supportive care and monitoring. Massive oral overdoses should be treated by emptying the gut if possible.
  • ​Hypotension Management:​ Do NOT treat hypotension with epinephrine (due to epinephrine reversal). Use phenylephrine or norepinephrine (levarterenol).
  • ​Seizure Management:​ Control seizures with barbiturates or diazepam.

製品

製剤

  • Oral Tablets
  • Injection
  • Oral Solution

ヒト用医薬品

  • Chlorpromazine Oral Tablets: 10 mg, 25 mg, 50 mg, 100 mg & 200 mg
  • Chlorpromazine Injection: 25 mg/mL in 1 & 2 mL amps

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

Protect from light and store at room temperature. Avoid freezing the oral solution and injection. Dispense oral solution in amber bottles. Store oral tablets in tight containers. Do not store in plastic syringes or IV bags for prolonged periods as the drug may adsorb to plastic. Discard darkly colored solutions or if precipitates have formed (a slight yellowish color will not affect potency).

飼主向け情報

  • ​取り扱い:​ 薬液が手や衣服につかないようにしてください。接触性皮膚炎（皮膚の炎症）を引き起こす可能性があります。投与後は手を洗ってください。
  • ​尿の色:​ この薬により、ペットの尿がピンク色または赤褐色に変色することがあります。これは正常な副作用であり、心配する必要はありません。
  • ​観察:​ 鎮静中は、ペットを安全で静かな環境に置いてください。過度の無気力、異常な筋肉の震え、またはこわばりがないか観察し、これらの症状が現れた場合は獣医師に連絡してください。

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