Travelers' diarrhea: antimicrobial therapy and chemoprevention

The use of preventive measures and self-treatment for travelers' diarrhea is routine in regions where the occurrence of diarrhea is predictably high. People traveling to these areas who do not exercise care in their selection of consumed foods and beverages will suffer high rates of illness. Such diarrhea normally affects the traveler for a day, although it can result in chronic postinfectious irritable bowel syndrome. Although systemic antibacterial drugs are effective in preventing diarrhea, their use is not routinely recommended because of side effects and their importance as a therapy for extra-intestinal infections. This review focuses on current and future uses of antibacterial drugs in the prevention and therapy of travelers' diarrhea. Minimally absorbed (< 0.4%) rifaximin can effectively reduce the occurrence of travelers' diarrhea without side effects. Bismuth subsalicylate is a useful alternative, although it is less effective than rifaximin for the prevention of travelers' diarrhea and the required doses are less convenient. All people who travel to high-risk areas should take curative antimicrobial agents with them for self-treatment of illness: rifaximin 200 mg three times a day for 3 days, or an absorbable agent such as a fluoroquinolone or azithromycin taken in a single dose initially, with the need for a second or third dose determined by clinical response. Loperamide (up to 8 mg per day for < or = 2 days) can be given with the antibiotic to offer rapid symptomatic improvement. In the future, the ability to evaluate the genetic risk of illness acquisition might allow person-specific recommendations to be made.