Xifaxan (rifaximin) – by mouth

What is a Westfarth?

Xifaxan (rifaximin) is an oral prescription antibiotic used to treat travelers’ diarrhea caused by certain bacteria and irritable bowel syndrome with diarrhea (IBS-D), a disease of the large intestine. Healthcare providers also prescribe Xifaxan to prevent hepatic encephalopathy (HE), a condition that causes changes in thinking, behavior, and personality in adults with liver disease.

These changes occur when toxins produced by certain bacteria in the gastrointestinal (GI) tract build up and enter the brain.

Xifaxan works by killing the bacteria that cause traveler’s diarrhea and IBS-D. In HE, Xifaxin kills the bacteria that produce the toxins that cause symptoms.

This medication is available in tablet form.

Drug Facts

Generic Name: Rifaximin

Brand name(s): Xifaxan

Route of Administration: Oral

Drug Availability: Prescription

Treatment Category: Antibiotics

Generally available: No

Controlled Substances: Not applicable

Active ingredient: Rifaximin

Dosage form: tablet

What is Xifaxan used for?

The U.S. Food and Drug Administration (FDA) approves Xifaxan to treat a variety of conditions, including:

  • Traveler’s Diarrhea: Treat travelers’ diarrhea caused by certain bacteria (Escherichia coli, or Escherichia coli) in adults and children 12 years and older. You should not use Xifaxan for diarrhea if you have blood in your stool or a fever. Traveler’s diarrhea refers to symptoms that develop within 10 days of travel to an area with poor public health. Drinking water or food contaminated with bacteria (or other microorganisms) can cause this condition. Traveling to developing countries in Asia, Africa, Central and South America, and the Middle East often presents the greatest risks.
  • Irritable Bowel Syndrome with Diarrhea (IBS-D): Rifaxamine is prescribed for people with IBS-D, usually after other treatments have failed. Several studies showed that a two-week trial of Xifaxan significantly improved symptoms of diarrhea and bloating.
  • Prevention of HE in adults with liver disease: People with liver disease have difficulty removing naturally occurring toxins from the body. When these toxins build up, they can enter the brain and cause symptoms, including confusion, slurred speech and reduced alertness.

How to take Silfax

Xifaxan is usually taken 2 to 3 times a day, depending on the medicines you are treating. Distribute the dose evenly throughout the day. You can take this medication with or without food.


Store Xifaxan at room temperature. Keep Xifaxan and all your medicines in a safe place away from children and pets at heights.

Off-label use

Your healthcare provider may prescribe Xifaxan for other uses not approved by the FDA. This is called off-label use.

Some off-label uses of Xifaxan include:

  • Pouchitis: A complication that affects the lining of the pouch during surgery for ulcerative colitis
  • Prevent Traveler’s Diarrhea
  • Small intestinal bacterial overgrowth: a condition that usually causes bloating, abdominal discomfort, and diarrhea
  • treat Clostridium difficile (C. Differences) infection after failure of other treatments
  • Treatment of HE

How long does it take Xifaxan to go to work?

How long it takes Xifaxan to work depends on the condition you are treating. With traveler’s diarrhea, most people start to feel better on the second day of treatment, but you should still complete the full treatment. IBS-D treatment usually takes two weeks of treatment. Prevention of hepatic encephalopathy requires long-term treatment.

What are the side effects of Xifaxan?

This is not a complete list of side effects, other side effects may occur. A medical professional can advise you about side effects. If you experience other effects, please contact your pharmacist or medical professional. You can report side effects to the FDA at www.fda.gov/medwatch or at 800-FDA-1088.

Like other medicines, Xifaxan can cause side effects. Tell your healthcare provider if you experience any side effects while taking this medication.

common side effects

Xifaxan is a well-tolerated drug. Most people don’t have any side effects.

However, the most common side effects include:

  • Dizziness
  • headache
  • joint pain
  • muscle spasms
  • nausea
  • nose or throat irritation
  • stomachache
  • tired

serious side effects

In rare cases, Xifaxan can cause serious side effects. Tell your healthcare provider right away if you experience any of the following reactions. If your symptoms are life-threatening, call 911.

Serious side effects of Xifaxan include:

  • swelling of the arms or legs (peripheral edema)
  • Swelling of the abdomen (ascites)
  • signs of an allergic reaction, including rash, hives, trouble breathing, or swelling of the mouth, face, lips, tongue, or throat
  • signs C. Differences Infection, a severe and potentially life-threatening form of diarrhea: Let your healthcare provider know if you have stomach pain, cramping, or very loose, watery, or bloody stools. Do not use any over-the-counter (OTC) medication for diarrhea without first talking to your provider.Serious complications can occur if you take over-the-counter antidiarrheal medicines C. Differences.

long term side effects

Although sifasin can be used for treatment C. Differences Infections, all antibiotics, including Xifaxan, can cause this. C. Differences Infections can occur several months after taking Xifaxan or after stopping treatment. C. Differences Sometimes serious, life-threatening intestinal problems can result. Tell your healthcare provider right away if you have stomach pain, cramping, or very loose, watery, or bloody stools.

Do not treat diarrhea without first talking to a medical professional.

report side effects

Xifaxan may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience serious side effects, you or your provider can send a report to the FDA’s MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

(800) 332-1088

Dosage: How much sifasin should I take?

Drug content provided and reviewed

IBM Micromedicine®

The dose of this medicine will vary for different patients. Follow your doctor’s order or directions on the label. The information below includes only the average dose of this medicine. If your dose is different, do not change it unless your doctor tells you to.

The amount of medicine you take depends on the strength of the medicine. In addition, the dose you take each day, the time allowed between doses, and the length of time you take the medication depend on the medical problem for which you are using the medication.

  • For oral dosage forms (tablets):

    • For the treatment of irritable bowel syndrome with diarrhea:

      • Adults – 550 milligrams (mg) 3 times a day for 14 days.
      • Children – use and dosage must be determined by your doctor.
    • To treat traveler’s diarrhea:

      • Adults and children 12 years and older – 200 milligrams (mg) 3 times a day for 3 days.
      • Children under 12 – Use and dosage must be determined by your doctor.
    • Prevention of hepatic encephalopathy:

      • Adults – 550 milligrams (mg) twice daily.
      • Children – use and dosage must be determined by your doctor.

missed dose

If you miss a dose of Xifaxan, take it as soon as you remember. If it’s almost time for your next dose, skip the missed dose and resume your normal dose schedule. Do not double or take extra.

Overdose: What will happen if I take too much Xifaxan?

Only a very small amount of Xifaxan is absorbed into your bloodstream from your gastrointestinal tract. Therefore, an overdose of sifaxan is not expected to cause any serious problems.

What will happen if I overdose on Xifaxan?

If you think you or someone else may have overdose on Xifaxan, call your healthcare provider or poison control center (800-222-1222).

If anyone passes out or is not breathing after taking Xifaxan, call 911 right away.



Drug content provided and reviewed

IBM Micromedicine®

It is very important for your doctor to check your or your child’s progress See if the medicine is working properly. This will allow your doctor to decide whether you or your child should continue taking it.

Contact your doctor right away if the diarrhea does not stop within 1 or 2 days, or if you or your child have a fever or blood in the stool.

If too much fluid is lost from the body due to diarrhea, a person may become dehydrated. Make sure you or your child drink plenty of fluids when you have diarrhea. Talk to your doctor right away if you or your child develops more than one of the following symptoms: decreased urination, dizziness, dry mouth, thirst, or lightheadedness.

Do not take other medicines unless discussed with your doctor. This includes prescription or over-the-counter (OTC) medicines [OTC]) medicines and herbal or vitamin supplements.

What are the reasons why I shouldn’t take sifaxan?

You should not take Xifaxan if you have had an allergic reaction to Xifaxan in the past or are allergic to other rifamycin antibiotics, including Rifadin or Rimactane (rifampin), Priftin (rifapentine), or Mycobutin (rifabutin).

What other drugs interact with Xifaxan?

Certain medicines may interact with Xifaxan. Be sure to let your healthcare provider know about all medicines you take, including over-the-counter vitamins, supplements, and herbal products.

Drugs that may interact with Xifaxan include:

  • Gengraf (cyclosporine)
  • Coumarin (Warfarin)

This is not a comprehensive list of all drugs that may interact with Xifaxan. Always consult your doctor or pharmacist before starting anything new.

Frequently Asked Questions

  • What is Xifaxan used for?

    Xifaxan is used to treat travelers’ diarrhea and diarrhea-predominant irritable bowel syndrome (IBS-D). Xifaxan is also used to prevent hepatic encephalopathy, which can cause confusion, slurred speech, and reduced alertness in people with liver disease. Your healthcare provider may also prescribe Xifaxan to treat other conditions.

  • How does Xifaxan work?

    Xifaxan is an antibiotic medicine. It works by killing the bacteria that cause some forms of traveler’s diarrhea and IBS-D. Xifaxan also kills the toxin-producing bacteria that cause symptoms of hepatic encephalopathy.

  • What are the side effects of Xifaxan?

    Xifaxan is a well-tolerated drug, but sometimes side effects can occur. Common side effects include dizziness, headache, joint pain, muscle cramps, nausea, nose or throat irritation, stomach pain, and tiredness.

How can I stay healthy while taking Xifaxan?

Xifaxan acts primarily in the gut and is rarely absorbed into the rest of the body. This makes sifasone a well-tolerated drug that most people take with no problem. However, all drugs carry certain risks.

Dietary changes can also help relieve diarrhea symptoms and relieve other symptoms associated with IBS-D. These include:

  • eat small meals often
  • Stay away from fatty and fried foods
  • Identify and Avoid Your IBS Trigger Foods

You can make other lifestyle adjustments to stay healthy, such as:

  • Limit drinking
  • Reduce exposure to toxins
  • Exercise and maintain a healthy weight
  • see your healthcare provider regularly

Tell your healthcare provider if you have any signs of a serious reaction, including swelling in your legs, arms, or abdomen. Reporting any adverse reactions right away will help you stay healthy and safe while taking Xifaxan or any other medicine.

Medical Disclaimer

VigorTip Health’s drug information is for educational purposes only and is not a substitute for medical advice, diagnosis or treatment by a healthcare professional. Consult your doctor before taking any new medicines. IBM Watson Micromedex provides some drug content as shown on the page.