Antisecretory and antiinflammatory properties of bismuth subsalicylate.

The antisecretory properties of Pepto-Bismol (PB) and its active ingredient, bismuth subsalicylate (BSS), were studied in ligated (rabbit and pig) and unligated (rat) intestinal-segment models. When PB was administered to segments before intestinal inoculation with heat-labile (LT) Escherichia coli or Vibrio cholerae enterotoxins, the inhibition of fluid accumulation was 74%-94% and 60%-91%, respectively. In the pig, the percentages of inhibition by PB of fluid accumulation produced by organisms or toxins were 69% for E. coli P57 producing heat-stable enterotoxin (ST), 89%-95% for E. coli P155 producing ST and LT, 52% for ST alone, 95% for LT alone, and 73% for ST and LT. When PB was administered to the pig immediately after inoculation with E. coli P57, E. coli P155, ST alone, LT alone, or ST and LT, the percentages of inhibition of fluid accumulation were 76%, 80%, 56%, 97%, and 69%, respectively. However, in the rabbit and rat, PB failed to inhibit fluid accumulation when it was administered 5-60 minutes after inoculation of cholera or E. coli LT enterotoxins. In the rabbit the combination of BSS and the vehicle of PB was synergistic in preventing the fluid accumulation normally produced by cholera toxin. Finally, when PB or BSS was administered 30 minutes before intestinal inoculation with arachidonic acid in a rat model of inflammatory diarrhea, the percentages of inhibition of fluid accumulation ranged, in a dose-responsive fashion, from 16% to 113% for PB and from 25% to 111% for BSS.