Xifaxan (rifaximin) is a prescription drug that’s used to treat diarrhea and a brain condition related to liver disease. Xifaxan can cause side effects that range from mild to serious. Examples include nausea and dizziness.

Xifaxan is used to:

The active ingredient in Xifaxan is rifaximin. (An active ingredient is what makes a drug work.) The drug comes as an oral tablet.

Keep reading to learn about the common, mild, and serious side effects that Xifaxan can cause. For a general overview of the drug, including details about its uses, see this article.

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

Below are just a few of the more common side effects reported by people who took Xifaxan in studies. These side effects can vary, depending on which condition the drug is being used to treat.

More common side effects in people taking Xifaxan for irritable bowel syndrome with diarrhea include:

Headache is a more common side effect in people taking Xifaxan for traveler’s diarrhea.

More common side effects in people taking Xifaxan for overt hepatic encephalopathy include:

* To learn more about this side effect, see the “Side effects explained” section below.

Xifaxan may cause mild side effects for some people. These side effects can vary, depending on which condition the drug is being used to treat.

Mild side effects that have been reported in people taking Xifaxan for irritable bowel syndrome with diarrhea include:

Mild side effects that have been reported in people taking Xifaxan for traveler’s diarrhea include:

Mild side effects that have been reported in people taking Xifaxan for overt hepatic encephalopathy include:

In most cases, these side effects should be temporary. And some may be easily managed. But if you have symptoms that are ongoing or bother you, talk with your doctor or pharmacist. And do not stop taking Xifaxan unless your doctor recommends it.

Xifaxan may cause mild side effects other than the ones listed above. See the drug’s prescribing information for details.

* To learn more about this side effect, see the “Side effects explained” section below.

Serious side effects can occur with Xifaxan. Some are more common, while others are rare. These side effects can vary, depending on which condition the drug is being used to treat.

Serious side effects have been reported with Xifaxan include:

If you develop serious side effects while taking Xifaxan, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

* To learn more about this side effect, see the “Side effects explained” section below.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Xifaxan, visit MedWatch.

Get answers to some frequently asked questions about Xifaxan’s side effects.

Can Xifaxan be used for SIBO? If so, does taking the drug for this condition cause certain side effects?

If your doctor recommends it, Xifaxan can be taken off label for small intestinal bacterial overgrowth (SIBO). With off-label use, doctors prescribe a drug for a purpose other than what it’s approved for.

SIBO occurs when you have too many bacteria in your small intestine. SIBO can lead to diarrhea, indigestion (upset stomach), or bloating.

To learn more about treatment options for SIBO, talk with your doctor. They can determine whether Xifaxan is the right treatment for this condition. If they prescribe Xifaxan for SIBO, your doctor will discuss possible side effects with you.

If I stop taking Xifaxan, will I experience certain side effects?

It’s unlikely. Stopping Xifaxan treatment isn’t known to cause any specific side effects. But stopping Xifaxan treatment early could cause the symptoms of your condition to return.

If you have questions about ending your Xifaxan treatment, talk with your doctor.

How long do side effects of Xifaxan usually last?

Studies of Xifaxan haven’t reported the length of time that side effects may last. But for many drugs, side effects are usually temporary. They’ll go away soon after you start or stop taking the drug.

If you’re having bothersome side effects while taking Xifaxan, talk with your doctor. They can advise you on ways to ease your symptoms.

Is weight gain a possible side effect of Xifaxan?

No, it’s unlikely. Weight gain wasn’t reported as a side effect in studies of Xifaxan. In fact, unintentional weight loss was reported in studies of Xifaxan for traveler’s diarrhea.

It’s important to note that weight loss can be a symptom of the conditions Xifaxan is used to treat. These include irritable bowel syndrome with diarrhea, traveler’s diarrhea, and hepatic encephalopathy. You may gain weight back as Xifaxan works to treat your condition.

If you’re concerned about weight gain with Xifaxan, talk with your doctor.

Learn more about some of the side effects Xifaxan may cause.

Nausea

Taking Xifaxan may cause nausea. In studies, this was a common side effect in people taking the drug.

What might help

While taking Xifaxan, talk with your doctor if you have nausea that’s bothersome or doesn’t go away. They can suggest ways to ease your symptoms. For example, they may suggest taking Xifaxan with food or taking bismuth subsalicylate (Pepto Bismol) for symptom relief.

Loss of taste

In some cases, taking Xifaxan may cause a loss of taste. In studies, this wasn’t a common side effect in people taking Xifaxan for traveler’s diarrhea. However, loss of taste wasn’t reported in studies of people taking Xifaxan for irritable bowel syndrome with diarrhea or overt hepatic encephalopathy.

What might help

If you experience loss of taste while taking Xifaxan, talk with your doctor. They can advise you on how long this side effect may last. Your doctor can also recommend other treatments for your condition that aren’t known to cause loss of taste.

Depression

In some cases, Xifaxan may cause depression. This wasn’t a common side effect in studies of people taking Xifaxan for overt hepatic encephalopathy. And depression wasn’t reported in studies of people taking Xifaxan for irritable bowel syndrome with diarrhea or traveler’s diarrhea.

Symptoms of depression can include:

  • feeling anxious, sad, or hopeless
  • changes in weight or appetite
  • trouble concentrating or making decisions
  • fatigue (low energy)

What might help

If you have symptoms of depression while taking Xifaxan, talk with your doctor. They can help determine whether Xifaxan or another factor may be the cause. And your doctor can recommend whether you should switch to a different treatment for your condition.

Allergic reaction

Like most drugs, Xifaxan can cause an allergic reaction in some people. However, this side effect was rare in people taking Xifaxan in studies.

Symptoms can be mild to serious and can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, usually in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms. Examples include:

If your doctor confirms you’ve had a mild allergic reaction to Xifaxan, they’ll decide whether you should continue taking it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Xifaxan, they may have you switch to a different treatment.

Keeping track of side effects

During your Xifaxan treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start taking a new drug or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of the drug you were taking when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how your symptoms affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help them learn more about how Xifaxan affects you. They can then use this information to adjust your treatment plan if needed.

Xifaxan may not be right for you if you have certain medical conditions. These are known as drug-condition interactions. Other factors may also affect whether Xifaxan is a good treatment option for you.

Talk with your doctor about your health history before starting Xifaxan. Factors to consider include those described below.

Severe liver disease. Before starting Xifaxan treatment, tell your doctor if you have severe liver disease such as cirrhosis. Having severe liver disease can raise the level of Xifaxan in your body, which may increase your risk of side effects from the drug.

If you have severe liver disease, your doctor can tell you whether Xifaxan is a safe treatment option. If they prescribe the drug for you, your doctor will monitor you closely for side effects during your treatment.

Allergic reaction. If you’ve had an allergic reaction to Xifaxan or any of its ingredients, your doctor will likely not prescribe Xifaxan. Ask them what other medications are better options for you.

Alcohol and Xifaxan

There is no known interaction between Xifaxan and alcohol.

But keep in mind that drinking alcohol can lead to diarrhea. Xifaxan is used to treat certain kinds of diarrhea. So, drinking alcohol while taking the drug could make it hard to tell if Xifaxan is working for your condition.

If you drink alcohol, talk with your doctor about how much (if any) may be safe to consume with your condition and treatment plan.

Pregnancy and breastfeeding with Xifaxan

It isn’t known whether Xifaxan is safe to take while pregnant or breastfeeding. It isn’t known whether the drug may harm a fetus or cause side effects in a child who’s breastfed.

If you have questions about taking Xifaxan while pregnant or breastfeeding, talk with your doctor. They can discuss the risks and benefits of Xifaxan treatment with you.

If you still have questions about side effects that Xifaxan can cause, talk with your doctor. Examples of questions to help get you started include:

  • How do Xifaxan’s side effects compare with those of other treatments for my condition?
  • Could any other medications I take increase my risk of side effects from Xifaxan?
  • Do any of my health conditions raise my risk of side effects from Xifaxan?

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Disclaimer: Healthline 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.