What is the proper administration and dosage of Pepto Bismol (bismuth subsalicylate)?

Pepto-Bismol (Bismuth Subsalicylate) Administration

For adults and children 12 years and older, administer 2 chewable tablets (524 mg bismuth subsalicylate) every 30-60 minutes as needed, not exceeding 8 doses (4,192 mg) in 24 hours, with tablets fully chewed before swallowing. 1

Standard Dosing by Indication

Acute Diarrhea

• Adults/children ≥12 years: 2 chewable tablets every 30 minutes OR 4 chewable tablets every hour 1
• Maximum: 8 doses (16 tablets total = 4,192 mg bismuth subsalicylate) in 24 hours 1
• Duration: Continue until diarrhea stops, but not more than 2 days 1
• Pediatric (<12 years): Consult physician before use 1

Upset Stomach, Heartburn, Indigestion, Nausea

• Adults/children ≥12 years: 2 chewable tablets every 30-60 minutes as needed 1
• Maximum: Same 8-dose limit applies 1

H. pylori Eradication (Bismuth Quadruple Therapy)

• Dosing: 2 tablets or capsules four times daily, 30 minutes before meals 2
• Duration: 14 days 2
• Combination: Given with tetracycline 500 mg four times daily (30 minutes after meals), metronidazole 500 mg four times daily (30 minutes after meals), and a proton pump inhibitor twice daily 2

Critical Administration Instructions

Chewable Tablets

• Must be fully chewed before swallowing 1
• Each chewable tablet contains 262 mg bismuth subsalicylate 1

Hydration

• Instruct patients to drink plenty of clear fluids to prevent dehydration caused by diarrhea 1

Pharmacokinetic Considerations

Salicylate Absorption

• Salicylate from bismuth subsalicylate is extensively absorbed (>90%) from the gastrointestinal tract 3, 4
• Peak plasma salicylate levels occur 0.5-3 hours after ingestion, averaging 40.1 ± 17.3 mcg/mL after a 60 mL dose 4
• After maximum daily dosing (4.2 g bismuth subsalicylate), peak salicylate concentrations remain considerably below toxic levels 3
• Approximately 95% of salicylic acid equivalents are recovered in urine 4

Bismuth Absorption

• Bismuth absorption is negligible (<0.005%) from the gastrointestinal tract 3, 5
• Plasma bismuth concentrations remain <1 ng/mL for the first 2 hours after dosing, with peak median concentration of only 1.7 ng/mL at 4 hours 5
• Extended dosing (3.14 g/day for up to 6 weeks) produces mean blood bismuth concentrations of 16.1 ± 7.9 ng/g, well below neurotoxic levels 3

Safety Profile

Duration Limits

• Acute use: Safe for short-term symptomatic relief 1, 3
• Extended use: Can be used safely for up to 3-4 weeks based on neurotoxicity studies 3
• H. pylori therapy: 14-day regimen is standard and safe 2

Mechanism of Action

• In the gastrointestinal tract, bismuth subsalicylate converts to salicylic acid and insoluble bismuth salts 3
• Demonstrates antisecretory properties, inhibiting fluid accumulation from enterotoxins by 52-97% depending on the toxin 6
• Exhibits antiinflammatory effects, inhibiting arachidonic acid-induced fluid accumulation by 16-113% in dose-responsive fashion 6

Common Pitfalls to Avoid

• Never exceed 8 doses (4,192 mg) in 24 hours to avoid salicylate toxicity 1
• Do not use for more than 2 days for acute diarrhea without physician consultation 1
• Always ensure tablets are fully chewed before swallowing for proper dissolution and absorption 1
• Children under 12 years require physician consultation before administration due to salicylate content and Reye's syndrome risk 1
• Emphasize hydration as dehydration from diarrhea is a primary concern 1