Bismuth Revisited: an Effective Way to Prevent Travelers— Diarrhea

J Travel Med 2004; 11:239–242. Approximately 35 million people travel from the rich world to developing countries annually.1 Of these, 20% to 50% will develop travelers’ diarrhea (TD), defined as the passage (during or up to 10 days after travel) of two or more watery or unformed stools over a 24-h period, or the passage of any number of stools when associated with fever, vomiting, or abdominal cramps.2 The mean duration of TD is only 3.6 0.1 days,2 and severe complications are rare.The impact of TD,however, is considerable, since it causes significant discomfort and loss of leisure time. Among healthy people, children and young adults are at increased risk.3,4 Young adults aged 20 to 29 years are thought to be at increased risk due to higher food consumption, riskier food and drink choices,or less prior exposure to etiologic agents.5 The most common causes of TD are bacteria, including enterotoxigenic Escherichia coli, Campylobacter jejuni, Salmonella spp. and Shigella spp. In 10% to 40% of cases no pathogen is isolated.5 To avoid TD,travelers should take sensible food and water precautions, such as avoiding untreated water and ice cubes, raw fruits and vegetables, unpasteurized milk and undercooked meat.6 Chemoprophylactic agents include bismuth subsalicylate, probiotics and antibiotics.There is evidence for the usefulness of probiotics to treat certain conditions.7 Their use to prevent TD, however, is rare and the value of this approach is uncertain. Antibiotics are sometimes prescribed for the prevention of TD. Fluoroquinolones, trimethoprim– sulfamethoxazole (TMP-SMX) and tetracyclines are all effective in preventing a significant proportion of cases. Side effects, cost and bacterial resistance, however, are significant concerns.Fluoroquinolones including ciprofloxacin, for example, are highly effective in preventing TD.8 They cover a wide range of species of bacteria, but resistance of Campylobacter spp.and E.coli is already emerging in many parts of the world.9,10 Side effects are common and include nausea, vomiting, rash, headache, dizziness and, less commonly, serious cardiac arrythmias.11 A 2-week course of ciprofloxacin (500 mg q.d.) costs a fairly substantial $70 to $80.12 TMP-SMX and tetracyclines also have common side effects but are considerably less expensive. It is important to keep in mind that, because antibiotics are normally available only by prescription, the cost of a doctor’s visit contributes to the overall cost of treatment.Overall, the Centers for Disease Control have concluded that the benefits of prophylactic antibiotic treatment are outweighed by the drawbacks, and do not recommend such treatment to prevent TD.13 Bismuth subsalicylate is a non-antimicrobial medication and the active compound in Pepto-Bismol. It has been used for many years to prevent TD and is widely available in North America without a prescription in both liquid and tablet forms.Unfortunately, availability is limited in Europe, Australia and New Zealand. A 2-week course costs only $10 to $15.14 The purpose of this systematic review is to determine the effectiveness of bismuth subsalicylate in the prevention of TD among healthy travelers.