Rifaximin is used to treat traveler’s diarrhea, such as that form E.coli. Rifaximin is not to be used for invasive diarrhea. An associated fever and bloody diarrhea indicate an invasive pathogen, such as campylobacter. When fever and bloody diarrhea are described, ciprofloxacin is the answer.
Rifaximin is a nonabsorbed version of the rifamycin antibiotic, rifampin. Rifaximin inhibits ribosomal RNA production of essential proteins.
There are no major adverse effects of rifaximin, because it is not absorbed from the gastrointestinal tract. It does not cause clostridium difficile colitis and may in fact treat it.