次サリチル酸ビスマス
次サリチル酸ビスマスは、市販の消化管保護薬および止瀉薬です。獣医学では、主に急性分泌性下痢の管理や、ヘリコバクター（*Helicobacter*）胃腸感染症を除菌するための「3剤併用療法」の成分として使用されます。 **臨床上の注意点：** - 親化合物は消化管内で分解され、**サリチル酸**を放出します。 - **猫への使用は要注意：** 猫はグルクロン酸抱合経路が欠如しているため、サリチル酸に対して非常に敏感です。高用量または反復投与により、容易にサリチル酸中毒を引き起こす可能性があります。 - 放射線不透過性であり、消化管のX線検査に影響を与える可能性があります。 - 飼い主は、ビスマスによって引き起こされる無害な黒色便をメレナ（消化管出血）と誤認することがよくあります。
作用機序: Bismuth subsalicylate is cleaved in the small intestine into **bismuth carbonate** and **salicylate**. - **Bismuth component:** Provides physical mucosal protection, binds bacterial endotoxins, and exhibits weak antibacterial properties (which contributes to its efficacy against *Helicobacter* spp.). - **Salicylate component:** Inhibits **cyclooxygenase (COX)** enzymes → decreases **prostaglandin** synthesis → reduces intestinal inflammation and hypersecretion, effectively mitigating clinical signs of secretory diarrhea.
動物種別の用量
- For diarrhea · 0.25 mL/kg · PO · q4-6h · Cats are sensitive to salicylates and probably should not receive frequent or high dosages
- For diarrhea · 0.5-1 mL/kg · PO · q12h · 3 days · Using 'Pepto-Bismol Regular' or equivalent strength (17.5 mg/mL) liquid
- For diarrhea in kittens and young cats · 1-2 mL · PO · 3-4 times a day · Refrigeration may increase palatability
- For eliminating Helicobacter gastritis infections (triple therapy) · 0.22 mL/kg · PO · q4-6h · 3 weeks · Given with Metronidazole 15.4 mg/kg q8h and amoxicillin 11 mg/kg q8h
- For eliminating Helicobacter gastritis infections (triple therapy) · 7.5 mg/kg · PO · q8h · 3-4 weeks · Given with Metronidazole 20 mg/kg and amoxicillin 30 mg/kg
- For eliminating Helicobacter gastritis infections (triple therapy) · 17.5 mg/kg · PO · q8h · 21 days · Given with Metronidazole 20 mg/kg PO q12h, amoxicillin 20 mg/kg PO q12h, famotidine 0.5 mg/kg PO once daily, and sucralfate 25 mg/kg PO q8h
- For diarrhea in calves · 60 mL · PO · two to four times a day · two days
- For diarrhea · 2-3 ounces · PO · 2-4 times a day
投与経路
禁忌
- Pre-existing bleeding disorders
- Known hypersensitivity to salicylates
- Use with extreme caution, if at all, in cats
有害事象
- Constipation or fecal impaction (especially in infants or debilitated patients)
- Stool discoloration (gray-black or greenish-black)
- Salicylism / salicylate toxicity (especially in cats or at high doses)
薬物相互作用
- Tetracycline · Bismuth can decrease the absorption of orally administered tetracyclines. Separate administration by at least 2 hours and give tetracycline first.
- Aspirin · Concomitant administration may increase salicylate serum levels, increasing the risk of toxicity.
モニタリング
- Clinical efficacy (resolution of diarrhea)
- Fluid and electrolyte status in severe diarrhea
- Signs of salicylate toxicity (especially in cats)
過量投与
Bismuth subsalicylate liquid/suspension contains approximately **8.7 mg/mL salicylate**. > **Note:** Two tablespoonsful (30 mL) is approximately equivalent to one 325 mg aspirin tablet. High doses can lead to **salicylism** (salicylate toxicity), which may manifest as gastrointestinal ulceration, bleeding, acid-base disturbances, and neurological signs. Cats are particularly vulnerable to overdose due to their deficient glucuronidation metabolism.
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