A randomized, double-blind, placebo-controlled study evaluating the efficacy and safety of rifaximin for the prevention of travelers' diarrhea in US military personnel deployed to Incirlik Air Base, Incirlik, Turkey.

BACKGROUND Infectious diarrhea is an important problem among travelers and deployed US military overseas causing substantial morbidity due to acute illness and may result in burdensome postinfectious sequelae. METHODS The nonsystemic antibiotic rifaximin was evaluated for prevention of travelers' diarrhea (TD) in a US military and civilian adult beneficiary population in a randomized, double-blind, placebo-controlled clinical trial. In all, 100 volunteers deployed to Incirlik Air Base, Turkey, received rifaximin 1,100 mg once daily or placebo for 2 weeks, and participants were followed daily for 2 weeks. RESULTS In an intention to treat analysis (n = 95), TD (based on subjects meeting case definition or early treatment) developed in 6.3% (3 of 48) of the rifaximin group compared with 19.2% (9 of 47) in the placebo group (Fisher's exact test p = 0.07). Rifaximin provided 67% (95% confidence interval, -13% to 91%, p = 0.07) protection against TD. Rifaximin 1,100 mg once daily was well tolerated with no observed differences in adverse events, whether solicited or unsolicited among the two treatment groups. CONCLUSIONS Rifaximin may represent an option among military personnel on deployment for prevention of TD with supportive future studies that consider deployment length, settings, and operational situations where widespread use of chemoprophylaxis may increase force health protection without undue risk during critical deployments.