R R

What Is Rifaximin?

Rifaximin is a prescription antibiotic belonging to the rifamycin class and is marketed under the brand name Xifaxan. It acts mainly within the digestive tract because relatively little of an oral dose enters the bloodstream. Rifaximin is approved for travelers' diarrhea caused by certain strains of Escherichia coli, reduction of recurrent overt hepatic encephalopathy in adults, and irritable bowel syndrome with diarrhea in adults. Its approved dosing differs according to the condition. Rifaximin is not appropriate for every intestinal infection and should not be used to treat travelers' diarrhea accompanied by fever or blood in the stool.

Link to This Resource Page

Provide a valuable resource to your clients or customers by linking to this resource page. Just place the following link on your website.

To display this...

What Is Rifaximin?

Rifaximin is a prescription antibiotic belonging to the rifamycin class and is marketed under the brand name Xifaxan. It acts mainly within the digestive tract because relatively little of an oral dose enters the bloodstream. Rifaximin is approved for travelers' diarrhea caused by certain strains of Escherichia coli, reduction of recurrent overt hepatic encephalopathy in adults, and irritable bowel syndrome with diarrhea in adults. Its approved dosing differs according to the condition. Rifaximin is not appropriate for every intestinal infection and should not be used to treat travelers' diarrhea accompanied by fever or blood in the stool.

read more about rifaximin ...

Copy this HTML:

Copy HTML Copied!

How Does Rifaximin Work?

Rifaximin binds to the beta subunit of bacterial DNA-dependent RNA polymerase, interfering with RNA synthesis and inhibiting the growth of susceptible bacteria. Unlike rifampin, rifaximin is poorly absorbed after oral administration and acts primarily inside the gastrointestinal tract. In travelers' diarrhea, it targets certain noninvasive strains of Escherichia coli. In hepatic encephalopathy, changes in intestinal bacterial activity can reduce the production of substances that contribute to neurological symptoms, including ammonia. Its mechanism in irritable bowel syndrome with diarrhea may involve changes in intestinal microbial activity, although the complete basis of clinical benefit is not established.

What Conditions Does Rifaximin Treat?

Rifaximin is approved for travelers' diarrhea caused by noninvasive Escherichia coli strains in adults and children aged 12 years and older. It is not indicated for travelers' diarrhea accompanied by fever or blood in the stool, or diarrhea caused by other pathogens. Rifaximin is also approved to reduce the risk of recurrent overt hepatic encephalopathy in adults with liver disease. Another indication is irritable bowel syndrome with diarrhea, or IBS-D, in adults. It is not approved for all cases of diarrhea, constipation-predominant IBS, or every intestinal infection. A clinician determines treatment according to symptoms, diagnosis, and potential interactions.

How Should Rifaximin Be Taken?

Rifaximin is taken orally, with or without food, according to the condition being treated. For travelers' diarrhea in patients aged 12 years and older, the recommended dose is 200 mg three times daily for three days. For reduction of recurrent overt hepatic encephalopathy in adults, the recommended dose is 550 mg twice daily. For IBS-D in adults, the recommended dose is 550 mg three times daily for 14 days. Patients with recurrent IBS-D symptoms may receive up to two additional courses using the same regimen. Rifaximin should not be used to conceal worsening diarrhea. Severe liver impairment and certain medication interactions require additional clinical consideration.

What Are the Side Effects and Warnings of Rifaximin?

Possible adverse effects include nausea, headache, dizziness, abdominal discomfort, and changes in bowel movements. In patients treated for hepatic encephalopathy, swelling and other complications related to underlying liver disease may also occur. Serious risks include allergic reactions and Clostridioides difficile-associated diarrhea, which can develop during or after antibiotic treatment. Rifaximin should not be used for travelers' diarrhea accompanied by fever or bloody stools because invasive infections may require different therapy. Exposure can increase in severe liver impairment and with certain transport-protein inhibitors such as cyclosporine. Severe allergic symptoms, persistent worsening diarrhea, or dehydration requires medical evaluation.

Common Questions About Rifaximin

Is rifaximin the same as Xifaxan?

Yes. Xifaxan is a brand name for rifaximin, an oral rifamycin antibiotic used for selected digestive and liver-related conditions.

Can rifaximin treat irritable bowel syndrome?

Yes. Rifaximin is approved for irritable bowel syndrome with diarrhea in adults, using a 14-day treatment course with limited retreatment when symptoms recur.

Can rifaximin prevent hepatic encephalopathy from returning?

Rifaximin is approved to reduce the risk of recurrent overt hepatic encephalopathy in adults. It may be prescribed alongside other treatments, such as lactulose.

Can rifaximin treat bloody travelers' diarrhea?

No. Rifaximin should not be used for travelers' diarrhea accompanied by fever or blood in the stool, which may indicate an invasive infection requiring different treatment.

References

DailyMed - XIFAXAN (rifaximin) tablet. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c5e8e2fd-7087-4b78-9181-cc259c0be2f1. Date Accessed November 3, 2026.

Rifaximin. LiverTox. https://www.ncbi.nlm.nih.gov/books/NBK548082/. Date Accessed November 3, 2026.

Rifaximin. MedlinePlus. https://medlineplus.gov/druginfo/meds/a604027.html. Date Accessed November 3, 2026.

Rifaximin. PubChem. https://pubchem.ncbi.nlm.nih.gov/compound/Rifaximin. Date Accessed November 3, 2026.

Rifaximin. PubMed. https://pubmed.ncbi.nlm.nih.gov/31643412/. Date Accessed November 3, 2026.