Pepto Bismol Dosing for Adults
Adults should take 2 chewable tablets (524 mg bismuth subsalicylate) every 30-60 minutes as needed, not exceeding 8 doses (4.2 g total) in 24 hours, with treatment duration limited to 2 days for diarrhea or acute gastrointestinal symptoms. 1
Standard Dosing Regimens
For Diarrhea
- Take 2 chewable tablets every 30 minutes OR 4 chewable tablets every hour 1
- Maximum: 8 doses (16 tablets total) in 24 hours 1
- Duration: Do not use for more than 2 days 1
- Drink plenty of clear fluids to prevent dehydration 1
For Upset Stomach, Heartburn, Indigestion, or Nausea
- Take 2 chewable tablets every 30 minutes to 1 hour as needed 1
- Same maximum daily limit applies: 8 doses in 24 hours 1
For H. pylori Eradication (Prescription Use)
- Take 2 tablets or 2 capsules four times daily, 30 minutes before meals 2
- Must be combined with tetracycline 500 mg four times daily (30 minutes after meals), metronidazole 500 mg four times daily, and a proton pump inhibitor twice daily 2
- Duration: 14 days for optimal eradication rates 2
Safety Profile and Absorption
Salicylate Absorption
- More than 90% of the salicylate component is absorbed systemically, reaching peak plasma concentrations 0.5-3 hours after ingestion 3, 4, 5
- Peak plasma salicylate levels average 40.1 ± 17.3 mcg/mL after a 60 mL dose, well below toxic concentrations 4
- The maximum daily dose (4.2 g bismuth subsalicylate) produces salicylate levels considerably below toxicity thresholds 3
Bismuth Absorption
- Less than 0.5% of bismuth is absorbed from the gastrointestinal tract, with negligible systemic exposure 3, 6, 5
- Peak plasma bismuth concentrations remain below 5.3 ng/mL with standard dosing, far below neurotoxic levels 5
- Extended dosing up to 6 weeks produces mean blood bismuth concentrations of 16.1 ± 7.9 ng/g, well below neurotoxicity thresholds 3
Critical Safety Considerations
Duration Limits
- For over-the-counter use, do not exceed 2 days of treatment 1
- Extended dosing (3-4 weeks) is safe only under medical supervision for specific indications like H. pylori treatment 3
Important Administration Details
- Fully chew tablets before swallowing for optimal effectiveness 1
- Maintain adequate hydration, especially when treating diarrhea 1
Drug Interactions
- Separate bismuth subsalicylate from fluoroquinolone antibiotics by at least 4 hours, as antacids significantly reduce fluoroquinolone absorption 7
Common Pitfalls to Avoid
- Do not exceed 8 doses in 24 hours, as this increases salicylate exposure and potential toxicity risk 1, 3
- Do not use for more than 2 days without medical consultation for acute symptoms 1
- Avoid in patients with salicylate allergy or those taking other salicylate-containing medications due to additive effects 3, 4
- Do not use in children under 12 years without physician guidance 1