Rifaximin

1 medicine

Rifaximin is a poorly absorbed gut-specific antibiotic used for travelers' diarrhea, IBS with diarrhea, and hepatic encephalopathy. It should not be used for diarrhea with fever or blood in the stool, since that points to an infection it cannot treat.

Xifaxan

Rifaximin

200/400/550mg

Xifaxan is a antibiotics medication containing Rifaximin, available as 200/400/550mg tablets.

from $0.71 / tablet View

Key facts

  • Rifaximin (Xifaxan) is an antibiotic that acts almost entirely inside the gut, with very little absorbed into the bloodstream.
  • It is taken as a short course for travelers' diarrhea, or regularly for IBS with diarrhea and to reduce recurrence of hepatic encephalopathy.
  • Do not use it for diarrhea with fever, blood in the stool, or worsening symptoms. Those signs suggest an invasive infection that rifaximin will not adequately treat.
  • Seek urgent care for diarrhea that persists beyond 24 to 48 hours, worsening abdominal pain, or fever.

What Rifaximin treats

Rifaximin treats travelers' diarrhea caused by non-invasive strains of E. coli, irritable bowel syndrome with diarrhea (IBS-D), and hepatic encephalopathy, the confusion caused by liver disease, where it reduces the risk of recurrent episodes. It is sometimes used for small intestinal bacterial overgrowth. It does not treat diarrhea caused by invasive bacteria, parasites, or viruses.

How Rifaximin works

Rifaximin blocks a bacterial enzyme, RNA polymerase, that bacteria need to copy their genetic material, stopping susceptible bacteria in the gut from multiplying. Because it is barely absorbed from the gut into the bloodstream, its effect stays largely local, limiting the whole-body antibiotic exposure seen with absorbed antibiotics.

Before you take it

  • Do not take rifaximin if you have had an allergic reaction to it or to other rifamycin antibiotics such as rifampicin.
  • Tell your prescriber if you have significant liver disease. Although absorption is normally minimal, liver impairment can raise blood levels of the drug.
  • Do not use it for diarrhea with fever or bloody stools; see a doctor instead, since a different treatment is needed.
  • Ciclosporin and some other drugs can raise rifaximin blood levels; mention all your medicines to your prescriber.

Side effects

Common effects include nausea, bloating, gas, and headache.

Seek urgent care for:

  • Diarrhea that is bloody, severe, or does not improve.
  • Signs of a serious allergic reaction: rash, swelling, or difficulty breathing.
  • New or worsening confusion in someone being treated for liver disease.

Safety essentials

  • Rifaximin is not a treatment for diarrhea with fever or blood in the stool. Using it for the wrong kind of infection can delay proper treatment and let the infection worsen.
  • Like other antibiotics, it can occasionally trigger Clostridioides difficile colitis; severe or persistent diarrhea during or after treatment needs medical review.
  • People with significant liver disease should be monitored, since higher systemic exposure is possible even though the drug mainly stays in the gut.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.