bismuth subsalicylate (Pepto Bismol, Kaopectate, Bismatrol Maximum Strength, and others)

  • Pharmacy Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

The safety and effectiveness of bismuth subsalicylate use in children <12 years has not been established.


Combining bismuth subsalicylate with sulfinpyrazone (Anturane) or probenecid is not recommended because bismuth subsalicylate may suppress the therapeutic effects of both drugs.

Tetracycline and quinolone antibiotics may form insoluble complexes with bismuth subsalicylate. While bismuth subsalicylate should be avoided in patients taking these antibiotics if possible, separating administration by 2 hours may be sufficient to avoid this interaction.

Bismuth subsalicylate should be used cautiously in patients taking methotrexate (Trexall). Bismuth subsalicylate is broken down to salicylic acid which is known to increase blood levels of methotrexate. Patients especially at risk for this interaction include those on high-dose methotrexate therapy, elderly patients, and patients with reduced kidney function.

Bismuth subsalicylate is broken down to salicylic acid. Pediatric patients should not be given salicylates for 6 weeks after receiving the varicella-zoster virus live vaccine (Zostavax, Varivax) due to the risk of developing Reye's syndrome, a serious liver disease.

PREGNANCY: Bismuth subsalicylate is known to cross the placenta following oral administration. Use of salicylates during pregnancy has been associated with adverse effects in the fetus. Therefore use of bismuth subsalicylate during pregnancy should be avoided. Bismuth subsalicylate is classified as FDA pregnancy risk category C (adverse effects in animals but inadequate human data).

NURSING MOTHERS: Salicylates are excreted into human milk and can cause harm to the nursing infant. Bismuth subsalicylate is thought to be harmful to the nursing infant and should be avoided during breastfeeding.

REFERENCE: FDA Prescribing Information.

Medically Reviewed by a Doctor on 5/12/2015

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