メペリジン
Meperidine
Meperidine hydrochloride
別名: Demerol · Alodan · Centralgine · Dolantina · Dolantine · Dolestine · Dolosal · Pethidine HCl · Isonipecaine · Meperidine hydrochloride · Pethidini hydrochloridum · Pethidinum
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Analgesic (extra-label)
認証済み獣医師の確認が必要
- q2-3h
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。
概要
メペリジン（別名ペチジン）は、主に鎮痛に使用される合成オピオイド作動薬です。
臨床上のポイント：
- 歴史的にはよく使用されていましたが、作用時間が非常に短く（犬や猫では1〜2時間未満）、特に静脈内投与時にヒスタミン遊離や低血圧を引き起こす傾向が高いため、現代の獣医療での使用は大幅に減少しています。
- 他の多くのオピオイドとは異なり、メペリジンは抗コリン作用（迷走神経遮断作用）および陰性変力作用を有しており、純粋なμ作動薬で通常見られる徐脈ではなく、頻脈を引き起こす可能性があります。
- 効力はモルヒネの約1/3〜1/8ですが、等鎮痛用量では同程度の呼吸抑制を引き起こします。
- 本剤はスケジュールII（C-II）の規制薬物です。
作用機序
Meperidine acts primarily as an agonist at the mu (μ) opioid receptors in the central nervous system (CNS) and peripheral tissues.
- Receptor Binding: Binds to G-protein coupled mu receptors → inhibits adenylate cyclase → decreases intracellular cAMP.
- Ion Channel Modulation: Promotes opening of potassium channels (causing hyperpolarization) and inhibits voltage-gated calcium channels (decreasing neurotransmitter release).
- Analgesia: Inhibits ascending nociceptive pathways and alters the perception of pain.
- Unique Mechanisms: Exhibits anticholinergic (vagolytic) effects and can cause direct mast cell degranulation leading to histamine release.
安全性・警告
禁忌
- Hypersensitivity to narcotic analgesics
- Patients receiving monamine oxidase inhibitors (MAOIs)
- Diarrhea caused by a toxic ingestion (until toxin is eliminated)
- Envenomations from Centruroides scorpion species, Gila monsters, or Mexican beaded lizards
- Intravenous (IV) administration
- Animals at risk from histamine release (e.g., skin allergies, asthma, mast cell tumours)
有害事象
- Respiratory depression
- Histamine release
- Bronchoconstriction (dogs)
- CNS depression
- Nausea and vomiting
- Decreased intestinal peristalsis
- Mydriasis (dogs)
- Salivation (especially cats)
- Physical dependence (chronic use)
- Tachycardia with PVCs (horses)
- Profuse sweating (horses)
- Hyperpnea (horses)
- Severe hypotension (if given IV rapidly)
- Hypotension (especially if given IV)
- Local urticaria (after IM injection)
- Dry mouth
- Pain on IM injection (due to volume)
- Neonatal sedation (if given to bitches prior to parturition)
注意事項
Important Administration Note: Many clinicians state meperidine should NOT be administered intravenously. If given IV, it must be given very slowly to avoid severe hypotension and histamine release. It may also be irritating when given SC.
- Extreme Caution: Patients with respiratory disease or acute respiratory dysfunction (e.g., pulmonary edema secondary to smoke inhalation).
- Caution: Hypothyroidism, severe renal insufficiency, adrenocortical insufficiency (Addison's disease), geriatric or severely debilitated patients.
- Caution: Head injuries or increased intracranial pressure, and acute abdominal conditions (e.g., colic) as it may obscure diagnosis.
- Equine Note: May potentiate intestinal obstruction secondary to reduced intestinal motility.
医薬品相互作用
May cause increased CNS or respiratory depression when used with meperidine.
Opiates may decrease efficacy in CHF patients.
Meperidine may enhance INH adverse effects.
Contraindicated. Can cause severe opiate overdose signs; avoid meperidine for at least 14 days after receiving MAOIs.
Meperidine may enhance neuromuscular blockade.
Meperidine may exacerbate the effects of tricyclic antidepressants.
Opiates may potentiate anticoagulant activity.
Increased CNS or respiratory depression
Serious interaction resulting in coma, convulsions, and hyperpyrexia
監視
- Respiratory rate and depth
- CNS level of depression or excitation
- Blood pressure (especially with IV use)
- Analgesic activity
- Pain score
- Heart rate
- Signs of histamine release (urticaria, bronchoconstriction)
薬物動態
半減期
吸収
Generally well absorbed orally, but a marked first-pass effect limits oral effectiveness. Peak analgesic effects occur between 30-60 minutes after IM or SC injection, with IM having a slightly faster onset.
分布
Widely distributed. Enters human breast milk at concentrations slightly higher than serum.
代謝
Metabolized primarily in the liver (mostly hydrolysis with some conjugation).
消失
Approximately 5% is excreted unchanged in the urine.
過剰投与
Overdosage may produce profound respiratory and/or CNS depression. Other effects can include cardiovascular collapse, hypothermia, and skeletal muscle hypotonia.
- Species Differences: Some species (especially cats) may demonstrate CNS excitability (hyperreflexia, tremors) and seizures at doses >20 mg/kg.
- Treatment: Naloxone is the agent of choice for respiratory depression. In massive overdoses, naloxone doses may need to be repeated, as its effects can diminish before subtoxic levels of meperidine are attained. Mechanical respiratory support should be considered. Pentobarbital has been suggested for CNS excitement/seizures in cats, but extreme caution is required as barbiturates and narcotics have additive respiratory depressant effects.
製品
製剤
- Injection
- Tablets
- Syrup/Oral Solution
- Injectable: 10-50 mg/ml solutions (50 mg/ml is most commonly used in veterinary practice)
動物用医薬品
- Pethidine 50 mg/ml injection
ヒト用医薬品
- Meperidine HCl Injection: 25 mg/mL, 50 mg/mL, 75 mg/mL, 100 mg/mL
- Meperidine HCl Tablets: 50 mg, 100 mg
- Meperidine HCl Syrup/Oral Solution: 50 mg/5 mL
- Demerol
- Meperidine injection
規制ステータス
POM (Prescription Only Medicine)
POM-V CD SCHEDULE 2
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Stable at room temperature. Avoid freezing the injectable solution and protect from light during storage. Does not exhibit significant adsorption to PVC IV bags or tubing.
飼主向け情報
重要： メペリジンは強力な処方鎮痛薬（オピオイド）であり、通常は獣医師の直接の監督下で病院内でのみ使用されます。
- 短時間作用型： この薬はペットの体内で非常に早く（多くの場合1時間未満で）効果が切れるため、通常は自宅に持ち帰るのではなく、処置中の注射として投与されます。
- 副作用： 眠気、吐き気、またはよだれを引き起こす可能性があります。経口投与の場合、液体や錠剤が口を刺激することがあり、特に猫で顕著です。
- 安全性： 獣医師の厳密な指示なしに、人間用の鎮痛薬や余ったメペリジンをペットに絶対に与えないでください。過剰摂取は生命を脅かす呼吸障害を引き起こす可能性があります。
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