bismuth subsalicylate (OTC)

Brand and Other Names:Kaopectate, Pepto Bismol, more...Maalox Total Relief, Kaopectate Extra Strength, Pepto-Bismol Maximum Strength
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Dosing & Uses


Dosage Forms & Strengths

tablet, chewable

  • 262mg
  • 525mg


  • 262mg

oral suspension

  • 262mg/15mL
  • 525mg/15mL
  • 525 mg/30 mL
  • 1050 mg/30 mL

Diarrhea, Gas, Upset Stomach, Indigestion, Heartburn, Nausea

2 tablets (262 mg/tab) or 30 mL (regular strength) PO q½-1hr PRN; maximum daily dose: 8 regular-strength doses or 4 extra-strength doses

Traveler's Diarrhea


2 tablets (262 mg/tab) q6hr for up to 3 weeks

Helicobacter Pylori

525 mg (2 regular-strength tablets or 1 extra-strength tablet) + 250 mg metronidazole + 500 mg tetracycline PO q6hr for 14 days, plus an H2 antagonist (Helidac Therapy pack)

Dosing Modifications

Renal impairment: Overdose may cause nephrotoxicity


Drink plenty of clear fluids to prevent dehydration caused by diarrhea

Do not use for >2 days

Helidac Therapy pack: Bismuth subsalicylate tablets should be chewed and swallowed; if a dose is missed, double doses should not be taken

Dosage Forms & Strengths

tablet, chewable

  • 262mg

oral suspension

  • 262mg/15mL
  • 525mg/15mL
  • 525 mg/30 mL
  • 1050 mg/30 mL

Diarrhea, Gas, Upset Stomach, Indigestion, Heartburn, Nausea

<3 years: Safety and efficacy not established

3-6 years: 1/3 tablet or 5 mL (regular strength) or 2.5 mL (extra strength) PO q½-1hr PRN

6-9 years: 2/3 tablet or 10 mL (regular strength) or 5 mL (extra strength) PO q½-1hr PRN

9-12 years: 1 tablet or 15 mL (regular strength) or 7.5 mL (extra strength) PO q½-1hr PRN

>12 years: 2 tablets or 30 mL (regular strength) or 15 mL (extra strength) PO q½-1hr PRN; maximum daily dose: 8 regular-strength doses or 4 extra-strength doses

Chronic Infantile Diarrhea

<2 years: 2.5 mL (regular strength) q4hr

2-4 years: 5 mL (regular strength) q4hr

4-6 years: 10 mL (regular strength) q4hr



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            Adverse Effects


            Nausea (12%)


            Diarrhea (7%)

            Abdominal pain (7%)

            Melena (3%)

            Upper respiratory tract infection (2%)

            Constipation (2%)

            Anorexia (2%)

            Vomiting (2%)

            Asthenia (2%)

            Discolored tongue (2%)

            Headache (2%)

            Dyspepsia (2%)

            Dizziness (2%)

            Stool abnormality (1%)

            Duodenal ulcer (1%)

            Sinusitis (1%)

            Taste perversion (1%)

            Flatulence (1%)

            GI hemorrhage (1%)

            Pain (1%)

            Insomnia (1%)

            Anal discomfort (1%)

            Paresthesia (1%)

            Frequency Not Defined






            Gray-black stool


            Muscle spasm

            Neurotoxicity (rare)




            Hypersensitivity to bismuth, aspirin, other salicylates

            Infectious diarrhea, high fever, von Willebrand disease, hemorrhage, ulcer or GI bleeding with black or bloody stool, hemophilia

            In pediatric patients, chicken pox or influenza (risk of Reye syndrome)


            Bismuth subcitrate potassium may cause temporary and harmless darkening of tongue and/or black stools, generally reversible within several days after treatment stopped; stool darkening should not be confused with melena

            Bismuth absorbs x-rays and may interfere with x-ray diagnostic procedures of gastrointestinal tract

            Cases of neurotoxicity associated with excessive doses of various bismuth-containing products reported; effects have been reversible with discontinuation of bismuth therapy

            Not to be administered to children or teenagers recovering from flu-like symptoms or chickenpox; increased incidence of Reye syndrome, associated with salicylate products


            Pregnancy & Lactation

            Pregnancy category: C; D in 3rd trimester

            Lactation: Salicylates enter breast milk; use with caution

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.



            Mechanism of Action

            Antimicrobial anti-inflammatory action (bismuth); antisecretory effect (salicylate)


            Bioavailability: Bismuth, <1%; salicylate, 80%

            Peak plasma time: Bismuth, 1.8-5 hr

            Onset: 4 hr


            Protein bound: Bismuth, 90%; salicylate, >90%

            Vd: Bismuth, 170 mL/kg


            Stomach: Bismuth subsalicylate is hydrolyzed in stomach to form slightly soluble bismuth oxychloride (BiOCl) and salicylic acid

            Small intestine: Unchanged bismuth subsalicylate passes into duodenum and reacts with other anions (eg, bicarbonate and phosphate) to form bismuth subcarbonate and bismuth phosphate salts

            Colon: BiOCl, bismuth subcarbonate, bismuth phosphate, and undissociated bismuth subsalicylate react with hydrogen sulfide (produced by colonic anaerobes) to form black bismuth sulfide, which is responsible for harmless darkening of stool and/or tongue

            Liver: Salicylate is extensively metabolized in liver

            Metabolites: Salicylate (active); BiOCl, bismuth subcarbonate, and bismuth phosphate (activity unknown)


            Half-life: Bismuth, 21-72 days; salicylate, 2.5 hr

            Excretion: Bismuth, feces (99%) and urine (0.003%); salicylate, urine (95%)

            Clearance: Bismuth, 50 mL/min



            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.