- Take the Pancreatitis Quiz
- Boost Digestive Health
- Digestive Distress Slideshow: Problem Foods to Avoid
- What is rifaximin, and how does it work (mechanism of action)?
- What brand names are available for rifaximin?
- Is rifaximin available as a generic drug?
- Do I need a prescription for rifaximin?
- What are the side effects of rifaximin?
- What is the dosage for rifaximin?
- Which drugs or supplements interact with rifaximin?
- Is rifaximin safe to take if I'm pregnant or breastfeeding?
- What else should I know about rifaximin?
What is rifaximin, and how does it work (mechanism of action)?
Rifaximin is a semi-synthetic antibiotic used for treating traveler's diarrhea and hepatic encephalopathy. It is derived from rifamycin, a naturally occurring chemical produced by a bacterium called Streptomyces mediterranei. Rifaximin is active against Escherichia coli bacterial strains that cause traveler's diarrhea, preventing growth of the bacteria by preventing them from manufacturing proteins needed for their replication and survival. By suppressing growth of the bacteria, rifaximin reduces symptoms of traveler's diarrhea. Hepatic encephalopathy is a serious neurologic complication of advanced liver disease that affects the brain. It is believed to be caused by the absorption of ammonia and other chemicals produced by bacteria in the intestine. It is believed that rifaximin prevents and treats hepatic encephalopathy by reducing the intestinal bacteria that produce ammonia. The FDA approved rifaximin in May 2004.
What are the side effects of rifaximin?
Common side effects associated with rifaximin include:
- urge to defecate,
- abdominal pain,
- flatulence, and
- fluid retention (edema).
Many of these side effects are also symptoms of traveler's diarrhea which rifaximin is used for treating. Rifaximin also causes allergic reactions, rash, and itching. Like other antibiotics rifaximin can alter the normal bacteria in the colon and encourage overgrowth of some bacteria such as Clostridium difficile which causes inflammation of the colon (pseudomembranous colitis). Patients who develop signs of pseudomembranous colitis after starting rifaximin (diarrhea, fever, abdominal pain, and possibly shock,) should contact their physician immediately.
What is the dosage for rifaximin?
The recommended dose for traveler's diarrhea is 200 mg 3 times daily for 3 days and the recommended dose for hepatic encephalopathy is 550 mg twice daily. Rifaximin may be administered with or without meals.
Which drugs or supplements interact with rifaximin?
Rifaximin does not interact with oral contraceptives and does not significantly interact with midazolam. Rifaximin has a low risk of drug interactions because it is poorly absorbed into the blood stream, and it does not significantly affect liver enzymes that break down most drugs.
Is rifaximin safe to take if I'm pregnant or breastfeeding?
The safety of rifaximin in pregnant women has not been adequately evaluated.
It is not known whether rifaximin is excreted in breast milk.
What else should I know about rifaximin?
What preparations of rifaximin are available?
Tablets: 200 and 550 mg
How should I keep rifaximin stored?
Rifaximin should be stored at room temperature at 15 C - 30 C (59 F - 86 F).
Quick GuideDigestive Disorders: Common Misconceptions
Rifaximin (Xifaxan) is a medication prescribed for the treatment of traveler's diarrhea, non-constipating IBS, and hepatic encephalopathy. Side effects, drug interactions, pregnancy safety, dosing information, and warnings and precautions should be reviewed prior to taking any medication.
Related Disease Conditions
Is C. diff (Clostridium difficile) Contagious?
C. diff, or Clostridium difficile, is a bacteria that infects the colon. C. diff bacteria can be found on furniture, bathroom...
Irritable Bowel Syndrome (IBS)
Irritable bowel syndrome (IBS) is a GI (gastrointestinal) disorder with signs and symptoms that include abdominal pain, bloating,...
Diarrhea (Causes, Medicine, Remedies, Treatment)
Diarrhea is a change is the frequency and looseness of bowel movements. Symptoms associated with diarrhea are cramping, abdominal...
Encephalopathy means brain disease, damage, or malfunction. Causes of encephalopathy are varied and numerous. The main symptom of...
SIBO (Small Intestinal Bacterial Overgrowth)
Small intestinal bacterial overgrowth (SIBO) refers to a condition in which abnormally large numbers of bacteria (at least...
IBS-D (Irritable Bowel Syndrome with Diarrhea)
IBS-D or irritable bowel syndrome with diarrhea refers to IBS with diarrhea. Symptoms of IBS-D include intestinal gas...
Travelers' diarrhea is generally contracted by eating contaminated food or drinking contaminated water. Food is the primary...
IBS vs. IBD: Differences and Similarities
IBS (irritable bowel syndrome) and IBD (inflammatory bowel disease) are both problems with the digestive tract...
Irritable Bowel Syndrome in Children (IBS)
Irritable bowel syndrome (IBS) in children is a functional gastrointestinal disorder with signs and symptoms of: Abdominal...
Travelers should prepare for their trip by visiting their physician to get the proper vaccinations and obtain the necessary...
Medications & Supplements
Prevention & Wellness
Health Solutions From Our Sponsors
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.