Bismuth subsalicylate in the treatment and prevention of diarrheal disease

Bismuth subsalicylate (BSS) has been used for more than 80 years to treat gastrointestinal symptoms although little clinical evidence was available until recently to substantiate its value and possible mechanisms of action. BSS 4.2 g given over 3 1/2 hours was shown to reduce the number of stools passed and favorably alter subjective symptoms in patients with traveler's diarrhea. BSS has also been shown to have beneficial effects on chronic infantile diarrhea. A small but discernible effect has been shown on selected symptoms associated with Norwalk virus-induced gastroenteritis. A liquid preparation, in a dose of 60 ml qid (4.2 g/d), was 62 percent effective in preventing traveler's diarrhea during a three-week period of risk and a tablet formulation (BSS 600 mg qid) was 76 percent effective in preventing experimentally induced enterotoxigenic Escherichia coli diarrhea in volunteers. A tablet formulation (2.1 g/d) was recently shown to be 65 percent effective in preventing traveler's diarrhea during a three-week clinical trial in Mexico. Preliminary evidence suggests that the salicylate moiety exerts antisecretory effects in patients with diarrhea and the bismuth and intestinal hydrolysis products of BSS have direct antimicrobial effects.