Bismuth subsalicylate

Indictions:

• Diarrhoea

  • The FDA-approved indications of BSS include diarrhea, heartburn, indigestions, nausea, and stomach upset. BSS is effective in situations where patients are experiencing mild gastrointestinal discomfort, as it reduces the severity and incidence of flatulence and diarrhea. Compared to placebo, BSS was able to provide greater and faster relief in patients with mild, moderate, and severe symptoms. BSS can be purchased over the counter and does not require a prescription; it has become a preferred self-treatment option for mild diarrhea, replacing the need for an antimicrobial.

• H. Pylori

  • One off-label indication for BSS is the management of Helicobacter pylori (H. pylori) gastrointestinal tract infection. Studies have shown that when used as part of a quadruple therapy regimen containing a proton pump inhibitor, tetracycline, and metronidazole, BSS eradicated up to 90% of H. pylori infections. The American Gastroenterological Association (AGA) suggests bismuth quadruple therapy as a first-line treatment option. This therapy is administered for 10 to 14 days and includes a proton pump inhibitor (PPI), bismuth, tetracycline, and nitroimidazole. This therapy combination is recommended for patients with previous macrolide exposure or who are allergic to penicillin

Mechanism of action

Bismuth subsalicylate (BSS) exhibits many properties due to its formulation as an insoluble salt of salicylic acid and trivalent bismuth. The mechanism of action through which BSS works is complex. In the stomach, BSS hydrolyzes into 2 compounds, bismuth and salicylic acid. The salicylate compound is almost completely absorbed into the bloodstream, while bismuth salt is minimally absorbed. The bismuth that remains in the gastrointestinal tract forms other bismuth salts. These bismuth salts contain bactericidal and antimicrobial activity and prevent bacteria from binding and growing on the mucosal cells of the stomach. This is the mechanism by which BSS helps eradicate H. pylori. Furthermore, preventing bacterial binding to the mucosal cells provides many benefits, including preventing intestinal secretion, promoting fluid absorption, reducing inflammation, and promoting the healing of any present ulcer in the stomach.

BSS does not appear to alter the normal flora of the stomach. However, its antimicrobial and antisecretory properties play a significant role in combating diarrhea. The antidiarrheal effect of BSS is most likely due to: 

• The reduction in prostaglandin formation, as BSS inhibits cyclooxygenase. Prostaglandin induces inflammation and hypermotility.
• The stimulation of reabsorption of fluids, sodium, and chloride; this action helps decrease fluid loss.
• The inhibition of intestinal secretions 

In peptic ulcer disease, the likely mechanism of BSS involves its cytoprotective and demulcent activity. In H. pylori infections, BSS blocks the adhesion of the bacteria to the gastric epithelial cells. Additionally, BSS inhibits H. pylori’s enzyme activities, including phospholipase, protease, and urease.