Rifaximin treatment of pathogen-negative travelers' diarrhea.
BACKGROUND
Antibacterial drugs appear to be effective in shortening the illness of a majority of cases of travelers' diarrhea.


METHODS
This was a subanalysis from two randomized, double-blind, placebo-controlled trials in adult travelers with acute diarrhea treated with rifaximin 200 mg three times a day or placebo for 3 days. Efficacy was assessed by the interval beginning with the first dose of medication and ending with the last unformed stool passed after becoming well [time to last unformed stool (TLUS)]; number of unformed stools passed; percent with clinical improvement; and incidence of wellness achieved.


RESULTS
Stool pathogens were not identified in pretreatment samples in 122 of 322 (38%) patients and 106 of 230 (46%) randomized to rifaximin and placebo, respectively. Among pathogen-negative patients, rifaximin was more effective than placebo for median TLUS (33 vs 68 h, p < 0.005), mean number of unformed stools passed (6.5 vs 8.6, p < 0.0001), and clinical wellness (77% vs 61%, p = 0.01). The adverse-event profiles between rifaximin and placebo were similar.


CONCLUSIONS
More than one third of patients with travelers' diarrhea had pathogen-negative illness. Rifaximin was effective in treating the illness without associated side effects. These results are consistent with the hypothesis that undetected bacterial pathogens are the most likely cause of travelers' diarrhea without definable cause.
DuPont
Herbert L
HL
Center for Infectious Diseases, Houston School of Public Health, The University of Texas, Houston, TX, USA. hdupont@sleh.com
Haake
Robert
R
Taylor
David N
DN
Ericsson
Charles D
CD
Jiang
Zhi-Dong
ZD
Okhuysen
Pablo C
PC
Steffen
Robert
R
D000284:Administration, Oral; D000328:Adult; D003967:Diarrhea / Q000188:drug therapy* / Q000382:microbiology / Q000473:pathology; D004311:Double-Blind Method; D005243:Feces / Q000382:microbiology; D005260:Female; D005765:Gastrointestinal Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D012294:Rifamycins / Q000008:administration & dosage / Q000627:therapeutic use*; D000078262:Rifaximin; D014195:Travel; D016896:Treatment Outcome
D005765:Gastrointestinal Agents; D012294:Rifamycins; D000078262:Rifaximin