パントプラゾール
パントプラゾールは強力な**プロトンポンプ阻害薬（PPI）**であり、胃潰瘍、びらん性食道炎、ストレス性粘膜疾患などの胃酸関連疾患の治療および予防に使用されます。 獣医学において最も広く認識されている経口PPIは**オメプラゾール**ですが、パントプラゾールはその**静脈内（IV）製剤**があるため、臨床現場で高く評価されています。これにより、経口薬に耐えられない、または消化管吸収が低下している入院中の重症患者（重度の膵炎、パルボウイルス性腸炎、または活動性消化管出血の犬や猫など）にとって優れた選択肢となります。 * **臨床のポイント：** 血漿中半減期は非常に短い（約1時間）ですが、受容体部位での不可逆的な結合により、臨床効果は24時間以上持続します。 * また、*in vitro*で*ヘリコバクター・ピロリ*の数を直接減少させることが示されており、一部の除菌プロトコルで利用されています。
作用機序: Pantoprazole is a substituted benzimidazole weak base. It accumulates in the highly acidic environment of the gastric parietal cell secretory canaliculi, where it is protonated and converted into its active sulfenamide form. * **Mechanism:** The active form binds **irreversibly via covalent disulfide bonds** to the **H+/K+ ATPase enzyme system** (the "proton pump") at the secretory surface of gastric parietal cells. * **Pathway:** Systemic circulation → Parietal cell → Acidic canaliculi → Active sulfenamide → **Irreversible inhibition of H+/K+ ATPase** → Profound suppression of both basal and stimulated gastric acid secretion. Because the binding is irreversible, acid secretion only resumes when new proton pump enzymes are synthesized by the parietal cell, explaining the prolonged duration of action despite rapid systemic clearance.
動物種別の用量
- Gastric acid suppression · 0.5-1 mg/kg · IV · q24h · Administer over 15 minutes
- All uses (ulcers, oesophagitis, hypersecretory conditions) · 0.7-1.0 mg/kg · IV · q24h · Not specified · Administer over 15 min. Oral dose not established but likely similar to IV dose.
- Gastric acid suppression in neonatal foals · 1.5 mg/kg · IV · once daily · From an experimental study evaluating normal neonatal foals. Further studies required for critically ill patients.
- Intravenous treatment of stress-related mucosal disease · 0.7-1 mg/kg · IV · once daily
- Gastric acid suppression · 0.5-1 mg/kg · IV · q24h · Administer over 15 minutes
- All uses (ulcers, oesophagitis, hypersecretory conditions) · 0.7-1.0 mg/kg · IV · q24h · Not specified · Administer over 15 min. Oral dose not established but likely similar to IV dose.
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
禁忌
- Known hypersensitivity to pantoprazole or other substituted benzimidazole PPIs
- Intramuscular (IM) or Subcutaneous (SQ) administration (parenteral form must be given IV)
- Intramuscular (IM) administration
- Subcutaneous (SC) administration
有害事象
- Diarrhea
- Headache (reported in humans)
- Hyperglycemia (rare, ~1% in humans)
- Injection site reactions (thrombophlebitis, abscess) with IV use
- Potential increased risk of community-acquired pneumonia (noted in human literature)
- Diarrhoea
- Headache
- Hyperglycaemia (rare)
- Increased risk of pneumonia
- Thrombophlebitis (associated with IV injection)
薬物相互作用
- Ketoconazole, itraconazole, iron, ampicillin esters · Decreased drug absorption due to increased gastric pH (these drugs require an acidic environment for optimal absorption)
- Sucralfate · May decrease the bioavailability of orally administered pantoprazole
- Warfarin · Pantoprazole may increase the anticoagulant effect
- Itraconazole · Decreased absorption of itraconazole due to increased gastric pH · moderate
- Ketoconazole · Decreased absorption of ketoconazole due to increased gastric pH · moderate
モニタリング
- Efficacy (resolution of clinical signs, improvement in gastric pH)
- Adverse effects (vomiting, diarrhea)
- Injection site reactions (thrombophlebitis, abscess) if used IV
- Resolution of clinical signs (vomiting, melena, regurgitation)
- Gastric pH (in critical care settings)
- IV catheter site for signs of thrombophlebitis
過量投与
Limited information available in veterinary species. A single oral dose of 887 mg/kg was lethal in dogs, causing acute toxic signs including ataxia, hypo-activity, and tremor. In humans, single oral overdoses up to 600 mg have been reported without adversity. In the event of a large overdose, contact an animal poison control center for guidance.
VetSheet の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。