Xifaxan is a brand-name prescription medication. It’s FDA-approved for the following conditions:

  • Traveler’s diarrhea. Xifaxan is used to treat traveler’s diarrhea in adults as well as children ages 12 years and older. For this purpose, the condition must be caused by certain strains of a bacterium called Escherichia coli (E. coli).
  • Overt hepatic encephalopathy. Xifaxan is used to reduce the risk of repeat episodes of overt hepatic encephalopathy in adults. This is a type of brain condition that’s due to liver damage. “Overt” means the condition causes symptoms that are noticeable and severe.
  • Irritable bowel syndrome with diarrhea. Xifaxan is used to treat a digestive condition known as irritable bowel syndrome with diarrhea in adults.

Xifaxan has limitations of use. For more information, see the “Xifaxan uses” section below.

Drug details

Xifaxan is an antibiotic that comes as an oral tablet. It’s available in two strengths: 200 milligrams (mg) and 550 mg.

Effectiveness

For information about the effectiveness of Xifaxan, see the “Xifaxan uses” section below.

Xifaxan is available only as a brand-name medication. It’s not currently available in generic form.

A generic drug is an exact copy of the active drug in a brand-name medication. Generics usually cost less than brand-name drugs.

Xifaxan contains the active drug rifaximin.

The Xifaxan dosage your doctor prescribes will depend on the type and severity of the condition you’re using the drug to treat.

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

Drug form

Xifaxan comes as an oral tablet.

Drug strengths: 200 mg, 550 mg

Xifaxan is available in two strengths: 200 milligrams (mg) and 550 mg.

Dosage for traveler’s diarrhea

When used to treat traveler’s diarrhea, the usual dosage of Xifaxan is 200 mg three times per day for 3 days.

Dosage for hepatic encephalopathy

Xifaxan is used to reduce the risk of repeat episodes of overt hepatic encephalopathy in adults. “Overt” means the condition causes symptoms that are noticeable and severe.

For this purpose, the usual dosage of Xifaxan is 550 mg two times per day. You’ll take this dosage for as long as your doctor advises.

Dosage for irritable bowel syndrome with diarrhea

When used to treat irritable bowel syndrome with diarrhea (IBS-D), the usual dosage of Xifaxan is 550 mg three times per day for 14 days. If your symptoms return after stopping treatment, your doctor may prescribe this dosage up to two more times.

Children’s dosage

Xifaxan is approved to treat traveler’s diarrhea in children ages 12 years and older. The dosage for children is the same as for adults. For details, see “Dosage for traveler’s diarrhea” above.

What if I miss a dose?

The manufacturer of Xifaxan hasn’t provided recommendations for a missed dose. If you miss a dose of the drug, talk with your doctor or pharmacist. They can advise you on whether you should take the missed dose of Xifaxan or skip it.

However, it’s important that you do not miss any doses of Xifaxan. A missed dose can increase the risk of your condition becoming resistant to the drug. This means Xifaxan won’t work as well for treating your condition.

To help make sure that you don’t miss a dose, try using a medication reminder. This can include setting an alarm or using a timer. You could also download a reminder app on your phone.

Will I need to take this drug long term?

Whether you’ll take Xifaxan long term depends on the condition the drug is used for.

For traveler’s diarrhea or IBS-D, you’ll likely take Xifaxan short term. For overt hepatic encephalopathy, you’ll usually take the medication long term.

If you have questions about how long your Xifaxan treatment will last, talk with your doctor.

Xifaxan can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Xifaxan. These lists do not include all possible side effects.

Side effects might differ slightly among people with traveler’s diarrhea, overt hepatic encephalopathy, or irritable bowel syndrome with diarrhea.

For more information about the possible side effects of Xifaxan, talk with your doctor or pharmacist. They can give you tips on how to manage any side effects that may be concerning or bothersome.

Note: The Food and Drug Administration (FDA) tracks side effects of drugs it has approved. If you’d like to notify the FDA about a side effect you’ve had with Xifaxan, you can do so through MedWatch.

Mild side effects

Below is a partial list of mild side effects of Xifaxan. To learn about other mild side effects, talk with your doctor or pharmacist, or view Xifaxan’s prescribing information.

Mild side effects of Xifaxan can include:

Most of these side effects may go away within a few days to a couple of weeks. However, if they become more severe or don’t go away, talk with your doctor or pharmacist.

* For more information about allergic reaction and Xifaxan, see “Allergic reaction” below.

Serious side effects

Serious side effects from Xifaxan aren’t common, but they can occur. Call your doctor right away if you have serious side effects. Call 911 or your local emergency number if your symptoms feel life threatening or if you think you’re having a medical emergency.

Serious side effects and their symptoms can include:

* For details about allergic reaction and Xifaxan, see “Allergic reaction” below.

ALLERGIC REACTION

As with most drugs, some people can have an allergic reaction after taking Xifaxan. This side effect wasn’t reported in clinical trials of the drug but has occurred since it was approved.

Symptoms of a mild allergic reaction can include:

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include:

  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your tongue, mouth, or throat
  • trouble breathing

Call your doctor right away if you have an allergic reaction to Xifaxan, as the reaction could become severe. Call 911 or your local emergency number if your symptoms feel life threatening or if you think you’re having a medical emergency.

As with all medications, the cost of Xifaxan can vary. The actual price you’ll pay depends on your insurance plan, your location, and the pharmacy you use.

Keep in mind that you may be able to get a 90-day supply of Xifaxan. If approved by your insurance company, getting a 90-day supply of the drug could reduce your number of trips to the pharmacy and help lower the cost. If you’re interested in this option, check with your doctor, pharmacist, or insurance company.

Before approving coverage for Xifaxan, your insurance company may require you to get prior authorization. This means that your doctor and insurance company will need to communicate about your prescription before the insurance company will cover the drug. The insurance company will review the prior authorization request and decide whether the drug will be covered.

If you’re not sure you’ll need prior authorization for Xifaxan, contact your insurance company.

Financial and insurance assistance

If you need financial support to pay for Xifaxan or help understanding your insurance coverage, help is available.

An Instant Savings Card is available for Xifaxan. For more information and to find out if you’re eligible for support, call 866-943-2926 or visit the drug website.

To learn more about saving money on prescriptions, check out this article.

Mail-order pharmacies

Xifaxan may be available through a mail-order pharmacy. Using this service may help lower the drug’s cost and allow you to get your medication without leaving home.

If recommended by your doctor, you may be able to receive a 90-day supply of Xifaxan, so there’s less concern about running out of the medication. If you’re interested in this option, check with your doctor, pharmacist, or insurance company. Some Medicare plans may help cover the cost of mail-order medications.

If you don’t have insurance, you can ask your doctor or pharmacist about online pharmacy options.

Generic version

Xifaxan is not available in a generic form. A generic drug is an exact copy of the active drug in a brand-name medication. Generics tend to cost less than brand-name drugs.

Here are answers to some frequently asked questions about Xifaxan.

Can Xifaxan be used for small intestinal bacterial overgrowth (SIBO)? If so, what’s the dosage?

Yes, Xifaxan can be used for small intestinal bacterial overgrowth (SIBO). The drug is not approved for this use but can be used off-label for this condition. Off-label drug use is when a drug the Food and Drug Administration (FDA) has approved is prescribed for a purpose other than what it’s approved for.

SIBO is a condition that occurs when too many bacteria grow in your small intestine. SIBO can lead to constipation, diarrhea, or bloating.

If you’re interested in treatment options for SIBO, talk with your doctor. They can help you decide whether Xifaxan may be the right treatment for this condition. And if your doctor recommends Xifaxan for SIBO, they’ll prescribe the proper dosage for you.

Is Xifaxan an antibiotic?

Yes, Xifaxan is an antibiotic.

Antibiotics are a class of drugs used to kill bacteria or slow their growth.

To learn more about Xifaxan’s uses and how the drug works for them, see the “Xifaxan uses” and “How Xifaxan works” sections below.

Does Xifaxan cause constipation?

It’s possible. Constipation was not reported as a side effect in clinical trials of Xifaxan. However, the drug’s manufacturer has noted that rare cases of constipation occurred when Xifaxan was used to treat irritable bowel syndrome with diarrhea.

If you’re concerned about Xifaxan and constipation, talk with your doctor. They can advise you on your risk of this side effect and ways to manage it.

The Food and Drug Administration (FDA) approves prescription drugs such as Xifaxan to treat certain conditions. Xifaxan may also be used off-label for other conditions. Off-label drug use is when an FDA-approved drug is prescribed for a purpose other than what it’s approved for.

Xifaxan for traveler’s diarrhea

Xifaxan is FDA-approved to treat traveler’s diarrhea in adults as well as children ages 12 years and older. For this purpose, the condition must be caused by certain strains of a bacterium called Escherichia coli (E. coli).

Note: Xifaxan has limitations of use. The drug’s manufacturer advises against using Xifaxan to treat traveler’s diarrhea that’s causing fever or bloody stool. And Xifaxan should not be used to treat traveler’s diarrhea due to bacteria other than E. coli. For more information, talk with your doctor.

Traveler’s diarrhea explained

Traveler’s diarrhea is a type of diarrhea that can occur when traveling to an area that’s not local to you. The diarrhea typically results from a bacterial infection in the digestive tract.

With traveler’s diarrhea, you have three or more loose stools in a 24-hour period. Symptoms usually start within 10 days of travel and may also include:

  • abdominal pain
  • fever
  • nausea and vomiting
  • bloody stool

Effectiveness for traveler’s diarrhea

Xifaxan has been found effective for treating traveler’s diarrhea. The drug is recommended as a treatment option in guidelines for traveler’s diarrhea by the Centers for Disease Control and Prevention (CDC).

To find out how the drug performed in clinical trials, see Xifaxan’s prescribing information.

Xifaxan for hepatic encephalopathy

Xifaxan is FDA-approved to reduce the risk of repeat episodes of overt hepatic encephalopathy in adults. “Overt” means the condition causes symptoms that are noticeable and severe.

Hepatic encephalopathy explained

Hepatic encephalopathy is a type of brain condition that’s due to liver damage.

Your liver usually helps remove harmful substances called toxins from your body. (An example of a toxin is ammonia.) If you have liver damage, your liver isn’t able to work properly and get rid of toxins. As a result, the toxins can build up in your blood and move to your brain. This can lead to a decline in brain function.

Symptoms of hepatic encephalopathy can include:

Hepatic encephalopathy is often reversible with treatment. However, people with liver damage are at risk of having repeated episodes of this condition. Xifaxan is used to reduce the risk of these repeated episodes.

Effectiveness for hepatic encephalopathy

Xifaxan has been found effective for reducing the risk of repeat episodes of hepatic encephalopathy. Treatment guidelines for hepatic encephalopathy recommend using the drug for this purpose. The guidelines are from the American Association for the Study of Liver Diseases and the European Association for the Study of the Liver.

To find out how the drug performed in clinical trials, see Xifaxan’s prescribing information.

Xifaxan for irritable bowel syndrome with diarrhea

Xifaxan is FDA-approved to treat irritable bowel syndrome with diarrhea (IBS-D) in adults.

Irritable bowel syndrome with diarrhea explained

IBS is a digestive condition that affects the intestines.

With IBS, you typically have symptoms such as bloating, gas, and abdominal pain. With IBS-D, you’ll have these symptoms together with diarrhea.

You can learn more about this condition by visiting our IBS hub.

Effectiveness for irritable bowel syndrome with diarrhea

Xifaxan has been found effective for treating IBS-D. Guidelines from the American College of Gastroenterology recommend Xifaxan for the relief of IBS-D symptoms.

To find out how the drug performed in clinical trials, see Xifaxan’s prescribing information.

Xifaxan and children

Xifaxan is FDA-approved to treat traveler’s diarrhea in children ages 12 years and older. For this purpose, the condition must be caused by certain strains of a bacterium called Escherichia coli (E. coli).

For details about traveler’s diarrhea, see “Xifaxan for traveler’s diarrhea” above.

Xifaxan isn’t known to interact with alcohol.

If you have questions about consuming alcohol during treatment with Xifaxan, talk with your doctor.

Xifaxan can interact with several other medications. However, it isn’t known to interact with supplements or foods.

Different interactions can cause different effects. For instance, some interactions can interfere with how well a drug works. Other interactions can increase side effects or make them more severe. Drug-condition interactions can also cause certain effects. For information about these interactions, see the “Xifaxan precautions” section below.

Xifaxan and other medications

Below is a list of medications that can interact with Xifaxan. This list does not contain all drugs that may interact with Xifaxan.

Before taking Xifaxan, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you take. Sharing this information can help you avoid potential interactions.

Types of drugs that can interact with Xifaxan include:

  • Cyclosporine. The medication cyclosporine (Gengraf, Neoral, Sandimmune) is used to help prevent organ rejection after an organ transplant. Taking Xifaxan with cyclosporine could increase the risk of side effects with Xifaxan.*
  • Warfarin. The drug warfarin (Jantoven) is used to help prevent or treat blood clots. Taking Xifaxan with warfarin could make warfarin less effective or increase the risk of side effects with warfarin.*

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

* For more information about side effects of Xifaxan, see the “Xifaxan side effects” section above.

Xifaxan and herbs and supplements

There aren’t any herbs or supplements that have been specifically reported to interact with Xifaxan. However, you should still check with your doctor or pharmacist before taking any of these products during Xifaxan treatment.

Xifaxan and foods

No foods have been specifically reported to interact with Xifaxan. If you have any questions about eating certain foods with Xifaxan, talk with your doctor.

Xifaxan is approved to treat traveler’s diarrhea, overt hepatic encephalopathy,* and irritable bowel syndrome with diarrhea (IBS-D) in certain situations. To learn more about these conditions, see the “Xifaxan uses” section above.

Traveler’s diarrhea typically results from a bacterial infection in the digestive tract. And certain bacteria are thought to play a role in hepatic encephalopathy and IBS-D.

Xifaxan is an antibiotic. The drug works by killing bacteria or slowing their growth. Xifaxan helps treat traveler’s diarrhea and IBS-D by reducing or limiting the number of bacteria. The medication also helps reduce the risk of repeated episodes of overt hepatic encephalopathy.

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

How long does it take to work?

How long it takes Xifaxan to work depends on the condition the drug is prescribed for.

For traveler’s diarrhea, symptoms usually ease within 3 days of starting treatment.

For IBS-D, it may take up to 2 weeks for symptom relief after you begin taking Xifaxan.

And it may take several weeks for Xifaxan to reduce your risk of having repeated episodes of overt hepatic encephalopathy.

Your doctor can tell you more about how soon Xifaxan may help your condition.

You should take Xifaxan according to the instructions your doctor gives you.

Xifaxan comes as an oral tablet that you swallow.

When to take

You’ll likely take Xifaxan two or three times per day. Try taking the medication around the same time each day. Doing so helps keep a steady level of the drug in your body. This helps Xifaxan work effectively.

To help make sure that you don’t miss a dose, try using a medication reminder. This can include setting an alarm or using a timer. You could also download a reminder app on your phone.

Accessible labels and containers

If your prescription label is hard to read, talk with your doctor or pharmacist. Some pharmacies offer labels that have 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 may be able to direct you to one that does.

If you have trouble opening medication bottles, ask your pharmacist if they can put Xifaxan in an easy-open container. They also may be able to recommend tools that can make it simpler to open lids.

Taking Xifaxan with food

You can take Xifaxan with or without food.

Can Xifaxan be crushed, split, or chewed?

The manufacturer of Xifaxan hasn’t stated whether or not the tablets can be crushed, cut in half, or chewed.

If you have trouble swallowing Xifaxan tablets, talk with your doctor or pharmacist. You can also refer to this article.

It’s not known whether Xifaxan is safe to take while pregnant. This drug hasn’t been studied during human pregnancy.

Animal trials have shown harm to offspring born to animals given Xifaxan during pregnancy. However, animal trials don’t always predict what happens with humans.

If you’re pregnant or planning a pregnancy, talk with your doctor. They can tell you about the risks and benefits of taking Xifaxan while pregnant.

It’s not known whether Xifaxan is safe to take during pregnancy. If you’re sexually active and you or your partner can become pregnant, talk with your doctor about your birth control needs while taking Xifaxan.

For more information about taking Xifaxan during pregnancy, see the “Xifaxan and pregnancy” section above.

It’s not known whether Xifaxan passes into breast milk or whether the drug could affect a child who is breastfed.

If you’re breastfeeding or planning to do so, talk with your doctor before starting Xifaxan treatment. They can recommend ways to feed your child.

This drug comes with several precautions. These are considered drug-condition interactions.

Before taking Xifaxan, talk with your doctor about your health history. Xifaxan may not be right for you if you have certain medical conditions or other factors affecting your health. These include:

  • Severe liver problems. Before taking Xifaxan, tell your doctor if you have a severe liver problem. An example is severe cirrhosis. Having a severe liver problem can raise the level of Xifaxan in your blood, which could increase your risk of side effects. If you have a severe liver problem, your doctor may watch you more closely than usual for side effects from Xifaxan.
  • Allergic reaction. If you’ve had an allergic reaction to Xifaxan or any of its ingredients, your doctor will likely not prescribe the drug. Ask them about other medications that may be better options for you.
  • Pregnancy. It isn’t known whether Xifaxan is safe to take during pregnancy. For more information, see the “Xifaxan and pregnancy” section above.
  • Breastfeeding. It’s not known whether Xifaxan passes into breast milk. To learn more, see the “Xifaxan and breastfeeding” section above.

Note: For more information about the potential negative effects of Xifaxan, see the “Xifaxan side effects” section above.

Do not take more Xifaxan than your doctor recommends. For some drugs, doing so may lead to unwanted side effects or overdose.

What to do in case you take too much Xifaxan

If you think you’ve taken too much of this drug, call your doctor. You can also call the American Association of Poison Control Centers at 800-222-1222 or use its online tool. However, if your symptoms are severe, call 911 or your local emergency number, or go to the nearest emergency room right away.

When you get Xifaxan from the pharmacy, the pharmacist will add an expiration date to the label on the bottle. This date is typically 1 year from the date they dispensed the medication.

The expiration date helps guarantee that the medication is effective during this time. The current stance of the Food and Drug Administration (FDA) is to avoid using expired medications. If you have unused medication that has gone past the expiration date, talk with your pharmacist about how to properly dispose of it.

Storage

How long a medication remains good to use can depend on many factors, including how and where you store the medication.

You should store Xifaxan oral tablets at a temperature from 68°F to 77°F (20°C to 25°C). You can store the drug at a temperature of 59°F to 86°F (15°C to 30°C) for short periods, such as when traveling. Be sure to keep the tablets in a tightly sealed container. Avoid storing this medication in areas where it could get damp or wet, such as bathrooms.

Disposal

If you no longer need to take Xifaxan and have leftover medication, it’s important to dispose of it safely. This helps prevent others, including children and pets, from taking the drug by accident. It also helps keep the drug from harming the environment.

This article provides several useful tips on medication disposal. You can also ask your pharmacist for information about how to dispose of your medication.

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.