Bismuth Subsalicylate
Bismuth subsalicylate is an over-the-counter gastrointestinal protectant and antidiarrheal agent. In veterinary medicine, it is primarily used to manage acute secretory diarrhea and as a component of 'triple therapy' for eradicating *Helicobacter* gastrointestinal infections. **Clinical Pearls:** - The parent compound is cleaved in the GI tract, releasing **salicylate**. - **Caution in Cats:** Because cats have deficient glucuronidation pathways, they are highly sensitive to salicylates. High or repeated doses can easily cause salicylism (toxicity). - It is radiopaque and may interfere with gastrointestinal radiologic examinations. - Owners frequently mistake the harmless bismuth-induced black stool for melena (GI bleeding).
Mecanismo: 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.
Dosificación por especie
- 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
Vías de administración
Contraindicaciones
- Pre-existing bleeding disorders
- Known hypersensitivity to salicylates
- Use with extreme caution, if at all, in cats
Efectos adversos
- 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)
Interacciones farmacológicas
- 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.
Monitoreo
- Clinical efficacy (resolution of diarrhea)
- Fluid and electrolyte status in severe diarrhea
- Signs of salicylate toxicity (especially in cats)
Sobredosis
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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