メトクロプラミド
Metoclopramide
Metoclopramide HCl
別名: Reglan · Metozolv · Emeprid · Metomotyl · Vomend · Maxolon · AHR-3070-C · DEL-1267 · metoclopramidi hydrochloridum · MK-745 · Metoclopramide hydrochloride
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
監査済み v13 用量エビデンス
構造化された用量計算エビデンスGastrointestinal stasis after obstruction has been excluded
認証済み獣医師の確認が必要
- q6–8h
必ず考慮する臨床コンテキスト (2)
- Exclude emergent diagnoses (obstruction, enterotoxemia)
- Prokinetic agent (after excluding the possibility of obstruction)
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
メトクロプラミドは、獣医療において広く使用されている消化管運動機能改善剤および制吐剤です。
- 消化管運動促進作用：主に上部消化管（胃および小腸）に作用し、結腸への影響は最小限です。胃うっ滞、胃食道逆流症、術後イレウスに臨床使用されます。
- 制吐作用：犬は化学受容器引き金帯（CRTZ）にドパミン受容体が豊富にあるため、非常に有効です。逆に猫はD2受容体が少ないため、猫における制吐剤としての信頼性は低くなります（マロピタントなどのNK-1拮抗薬が好まれることが多いです）。
臨床のポイント：
- パルボウイルス性腸炎や急性膵炎などの重篤な状態に対して、持続静脈内点滴（CRI）として投与されることがよくあります。
- 血液脳関門を通過するため、特に高用量や馬などの感受性の高い動物種において、顕著な錐体外路症状（振戦、落ち着きのなさ、狂乱行動など）を引き起こす可能性があります。
作用機序
Metoclopramide exerts its effects through both peripheral gastrointestinal and central nervous system mechanisms:
- Peripheral (GI Tract): Sensitizes upper GI smooth muscle to acetylcholine → increases tone and amplitude of gastric contractions, relaxes the pyloric sphincter, and increases duodenal and jejunal peristalsis. It also increases lower esophageal sphincter (LES) pressure, reducing reflux.
- Central (CNS): Antagonizes Dopamine (D2) receptors in the Chemoreceptor Trigger Zone (CRTZ) → blocks emetic signaling to the vomiting center, providing a potent central antiemetic effect.
- Additional Mechanisms: At higher doses, it exhibits weak 5-HT3 (Serotonin) receptor antagonism and 5-HT4 receptor agonism, further contributing to its antiemetic and prokinetic profiles.
安全性・警告
禁忌
- GI hemorrhage
- GI obstruction or perforation
- Hypersensitivity to metoclopramide
- Seizure disorders (relatively contraindicated, lowers seizure threshold)
- Head trauma
- Pheochromocytoma (may induce hypertensive crisis)
- Concurrent phenothiazine therapy
- Dogs with pseudopregnancy (stimulates prolactin release)
- Gastrointestinal obstruction
- Gastrointestinal perforation
- Gastrointestinal hemorrhage
- Seizure disorders (epilepsy)
有害事象
- Dogs: Changes in mentation and behavior (motor restlessness, involuntary spasms, aggression, hyperactivity to drowsiness/depression), constipation
- Cats: Frenzied behavior, disorientation, constipation
- Horses: Severe CNS effects (IV use), alternating sedation and excitement, behavioral changes, abdominal pain
- Extrapyramidal effects (tremors, rigid posture)
- Nausea and diarrhea
- Transient hypertension
- Elevated prolactin levels
- Extrapyramidal signs (tremors, twitching, hyperactivity, restlessness)
- Constipation or diarrhea
- Changes in mentation or behavior
注意事項
Absolute Contraindication: Do not use in patients with suspected or confirmed GI obstruction, perforation, or hemorrhage.
- Use with extreme caution in patients with a history of seizures, as metoclopramide can lower the seizure threshold.
- Dosage adjustment (reduce CRI by 25-50%) may be required in patients with renal failure.
- Avoid use in dogs experiencing pseudopregnancy due to its prolactin-stimulating effects.
- Monitor closely for extrapyramidal signs (involuntary muscle spasms, rigidity, tremors), which can be reversed with anticholinergic agents like diphenhydramine.
医薬品相互作用
Metoclopramide may enhance the absorption of these agents.
Acute hypotension has been reported if metoclopramide is used concurrently IV.
May antagonize the GI motility effects of metoclopramide.
Oral metoclopramide increases cephalexin peak plasma concentrations and AUC in dogs.
May enhance metoclopramide's GI effects.
Metoclopramide may enhance CNS depressant effects.
Metoclopramide increases the rate and extent of GI absorption.
May antagonize the GI motility effects and enhance metoclopramide's CNS effects.
Could cause hypertension.
May potentiate the extrapyramidal effects of metoclopramide.
Reduces induction requirements of propofol by 20-25%.
Potential for enhanced extrapyramidal effects.
Metoclopramide increases the rate and extent of GI absorption.
Increased risk of extrapyramidal effects and CNS depression
May antagonize the gastrointestinal prokinetic effects of metoclopramide
Antagonize the prokinetic effects on the gastrointestinal tract
監視
- Clinical efficacy (resolution of vomiting, improved GI transit)
- Adverse effects (especially CNS and extrapyramidal signs)
- Clinical response (reduction in vomiting, improved gastric emptying)
- Hydration status and electrolyte balance
- Signs of extrapyramidal adverse effects (twitching, restlessness)
薬物動態
半減期
吸収
Well absorbed after oral administration, but a significant first-pass effect may reduce systemic bioavailability to ~30% (high interpatient variation). Bioavailability after IM administration is 74-96%. Peak plasma levels generally occur within 2 hours after oral dosing.
分布
Well distributed in the body and enters the CNS. Weakly bound to plasma proteins (13-22%). Crosses the placenta and enters milk in concentrations approximately twice those of plasma.
代謝
The majority of the drug is metabolized to glucuronidated or sulfated conjugate forms.
消失
Primarily excreted in the urine (20-25% unchanged, the rest as metabolites). Approximately 5% is excreted in the feces.
過剰投与
The oral LD50 doses are very high (465-870 mg/kg in laboratory animals), making death from oral overdose unlikely in veterinary patients.
Clinical Signs of Toxicity:
- Sedation, ataxia, agitation
- Extrapyramidal effects (tremors, rigidity, spasms)
- Nausea, vomiting, constipation
Treatment:
- No specific antidote exists.
- If ingestion was recent, empty the stomach using standard protocols.
- Anticholinergic agents that enter the CNS (e.g., diphenhydramine at 2.2 mg/kg IV, or benztropine) are highly effective in controlling extrapyramidal effects.
- Peritoneal dialysis or hemodialysis is not effective for drug removal.
製品
製剤
- Oral Tablets: 5 mg, 10 mg
- Oral Disintegrating Tablets: 5 mg, 10 mg
- Oral Syrup: 1 mg/mL
- Injection Solution: 5 mg/mL
- Injectable: 5 mg/ml solution
- Oral: 1 mg/ml solution
動物用医薬品
- None
- Emeprid 5 mg/ml injectable solution
- Emeprid 1 mg/ml oral solution
- Metomotyl
- Vomend
ヒト用医薬品
- Metoclopramide HCl Oral Tablets: 5 mg & 10 mg (Reglan, Metozolv, generic)
- Metoclopramide HCl Oral Disintegrating Tablets: 5 mg & 10 mg
- Metoclopramide HCl Oral Syrup: 1 mg/mL
- Metoclopramide HCl Injection Solution: 5 mg/mL (Reglan, generic)
- Maxolon
規制ステータス
Classified as POM-V (Prescription Only Medicine - Veterinarian).
Classified as POM-V.
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Photosensitive; must be stored in light-resistant containers at room temperature. Tablets should be kept in tight containers. Injection is stable in solutions with a pH of 2-9 and compatible with D5W, 0.9% NaCl, Ringer's, and LRS.
飼主向け情報
メトクロプラミドは、胃を空にし、吐き気や嘔吐を防ぐために使用されます。
- 投与方法：消化管運動促進効果を最大限に引き出すため、ペットの食事の約30分前に投薬してください。
- 行動の変化：異常な行動がないか観察してください。犬では、落ち着きのなさ、うろうろ歩き回る、攻撃性として現れることがあります。猫では、狂乱行動や見当識障害として現れることがあります。
-
緊急の警告：ペットに不随意の筋肉のけいれん、目・顔・手足のひきつり、または硬直した姿勢が見られた場合は、直ちに獣医師に連絡してください。これらは錐体外路症状と呼ばれ、獣医師が処方する特定の薬で迅速に回復させることができます。
- 薬は室温で保管し、直射日光を避けてください。
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。