Xifaxan (rifaximin) is a brand-name drug that’s prescribed for conditions including traveler’s diarrhea in adults and some children. Xifaxan comes as an oral tablet that’s typically taken twice per day.

Xifaxan belongs to a drug class called antibiotics. Xifaxan isn’t available in a generic version.

Keep reading for specific information about the dosage of Xifaxan, including its strengths and how to take the medication. For a comprehensive look at Xifaxan, including details about its uses, see this article.

Note: This article describes typical dosages for Xifaxan provided by the drug’s manufacturer. When taking Xifaxan, always follow the dosage prescribed by your doctor.

Below is information about Xifaxan’s recommended dosages.

Xifaxan form

Xifaxan comes as an oral tablet.

Xifaxan strengths

Xifaxan tablets come in two strengths: 200 milligrams (mg) and 550 mg.

Typical dosages

The following information describes dosages that are commonly prescribed or recommended in adults. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Dosage for traveler’s diarrhea

The typical dosage of Xifaxan for traveler’s diarrhea in adults is 200 mg three times per day for 3 days.

Dosage for irritable bowel syndrome with diarrhea

The typical dosage of Xifaxan for irritable bowel syndrome with diarrhea (IBS-D) in adults is 550 mg three times per day for 14 days. If your diarrhea comes back, your doctor may prescribe the same dosage regimen up to two more times.

Dosage for hepatic encephalopathy

The typical dosage of Xifaxan for hepatic encephalopathy (HE) in adults is 550 mg two times per day. You’ll take this dosage for as long as your doctor recommends.

Note: Xifaxan is used to help prevent repeat episodes of overt HE due to liver cirrhosis. “Overt” means the symptoms are noticeable and severe.

Children’s dosage

Xifaxan is used to treat traveler’s diarrhea in children ages 12 years and older. The typical dosage is the same as the adult dosage: 200 mg three times per day for 3 days.

Long-term treatment

For traveler’s diarrhea and IBS-D, Xifaxan isn’t meant to be taken long term. If your doctor prescribes Xifaxan for these conditions, you’ll typically take the drug for 3–14 days.

If your doctor prescribes Xifaxan for HE, you’ll likely take it for as long as recommended.

Below are some frequently asked questions about Xifaxan’s dosage.

Do I need to take my Xifaxan dose before or after food?

You can take your Xifaxan dose before or after food. Xifaxan comes as a tablet you swallow with or without food. Always follow your doctor’s directions for taking Xifaxan. For details, refer to the “How to take Xifaxan” section below.

If you have more questions about how to take Xifaxan, talk with your doctor or pharmacist.

Can Xifaxan be used for small intestinal bacterial overgrowth (SIBO) or liver cirrhosis? If so, what is the dosage?

Xifaxan may be used off label for small intestinal bacterial overgrowth (SIBO). With off-label use, a drug is prescribed for a purpose other than what it’s approved for. Xifaxan is approved to help prevent repeat episodes of overt* hepatic encephalopathy (HE) due to liver cirrhosis. It’s also approved to treat traveler’s diarrhea and irritable bowel syndrome with diarrhea (IBS-D).

With SIBO, too many bacteria grow in your small intestine. The symptoms can include bloating, diarrhea, and constipation. If you’re interested in Xifaxan for SIBO, talk with your doctor. If they prescribe the drug, they’ll determine the right dosage for you.

To find out the typical dosage for HE and Xifaxan’s other approved uses, see the “Xifaxan dosage” section above.

* “Overt” means the condition causes noticeable and severe symptoms.

The Xifaxan dosage your doctor prescribes will depend on several factors. These include:

  • the type and severity of the condition you’re taking Xifaxan to treat
  • other medical conditions you may have

Talk with your doctor if you have questions about the Xifaxan dosage they recommend for you.

Xifaxan comes as a tablet you swallow, with or without food. The drug manufacturer doesn’t say whether to crush, chew, or split the tablets.

If you have trouble swallowing tablets, see this article for tips on how to take this form of medication. You can also talk with your doctor or pharmacist.


Some pharmacies offer labels with large print, braille, or a code you scan with a smartphone to convert text to speech. If your local pharmacy doesn’t have these options, your doctor or pharmacist might be able to recommend a pharmacy that does.

If you’re having trouble opening medication bottles, ask your pharmacist about putting Xifaxan in an easy-open container. They also may recommend tools that can make it easier to open bottles.

The drug manufacturer doesn’t provide guidance on missed doses. If you miss a dose of Xifaxan, ask your doctor or pharmacist what they recommend.

To help make sure that you don’t miss a dose, try using a medication reminder. This can include setting an alarm or putting a note where you’ll see it, such as on your bathroom mirror or bedside table. You could also download a reminder app on your phone.

It’s important that you do not take more Xifaxan than your doctor prescribes. For some medications, taking more than the recommended amount may lead to harmful effects or overdose.

If you take more than the recommended amount of Xifaxan

Call your doctor right away if you believe you’ve taken too much Xifaxan. Another option is to call America’s Poison Centers at 800-222-1222 or use its online tool. If you have severe symptoms, immediately call 911 or your local emergency number, or go to the nearest emergency room.

The dosages in this article are typical dosages provided by the drug’s manufacturer. If your doctor recommends Xifaxan for you, they’ll prescribe the dosage that’s right for you. Always follow the dosage that your doctor prescribes.

As with any drug, never change your dosage of Xifaxan without your doctor’s recommendation. If you have questions about the dosage of Xifaxan that’s best for you, talk with your doctor.

Besides learning about dosage, you may want other information about Xifaxan. These additional articles might be helpful:

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.