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Bismuth salt (anti-diarrhoeal / antacid)

Bismuth subsalicylate

Brand names: Pepto-Bismol

Adult dose

Dose: 525mg PO q30–60min PRN (max 4.2g/day); travellers' diarrhoea prophylaxis 525mg QDS
Route: Oral
Frequency: PRN

Clinical pearls

  • NaTHNaC TravelHealthPro: travellers' diarrhoea symptomatic relief / prophylaxis
  • NICE CKS Diarrhoea
  • Available OTC

Contraindications

  • Aspirin / salicylate hypersensitivity
  • Active GI bleeding
  • Children with viral illness (Reye's syndrome)
  • Severe renal impairment
  • Pregnancy

Side effects

  • Black stools / tongue
  • Salicylate toxicity (high doses)
  • Constipation
  • Reye's syndrome (children)

Interactions

  • Anticoagulants
  • Tetracyclines / quinolones (chelation)
  • Aspirin/NSAIDs (additive salicylate)

Monitoring

  • Symptom resolution
  • Salicylate effect (high dose)

Reference: BNF; NaTHNaC; NICE CKS; https://bnf.nice.org.uk/drugs/bismuth-subsalicylate/. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.