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Can Xifaxan Cause Diarrhea?

Key Takeaways

  • Yes, Xifaxan (rifaximin) can cause diarrhea, although it is more commonly prescribed to treat certain types of diarrhea, such as traveler’s diarrhea caused by Escherichia coli (E. coli) and IBS-D (irritable bowel syndrome with diarrhea).
  • Diarrhea is considered a possible side effect, but it is not among the most frequently reported ones.
  • Xifaxan is minimally absorbed into the bloodstream, so most side effects are gastrointestinal, including bloating, abdominal pain, constipation, nausea, or changes in bowel movements.
  • Severe symptoms, especially if you suspect C. difficile (Clostridioides difficile) colitis, require immediate medical attention.
  • Talk to your healthcare provider if new or worsening diarrhea occurs while using Xifaxan, especially if you have liver disease, hepatic encephalopathy, or take interacting medications such as cyclosporine or warfarin.

What Is Xifaxan?

Xifaxan is the brand name for rifaximin, an antibiotic in the rifamycin drug class. It is FDA-approved for:

  • Traveler’s diarrhea caused by E. coli
  • IBS-D (irritable bowel syndrome with diarrhea)
  • Hepatic encephalopathy to reduce the risk of episodes

Xifaxan is also commonly taken off-label to ease the symptoms of a GI condition called small intestinal bacterial overgrowth (SIBO).

Xifaxan works primarily in the gastrointestinal tract and is poorly absorbed into the bloodstream, which limits systemic side effects.

Can Xifaxan Actually Cause Diarrhea?

Yes, while Xifaxan is often used to treat diarrhea, clinical studies show that a small number of patients may experience:

  • Worsening diarrhea
  • New onset diarrhea
  • Diarrhea after finishing treatment

This can happen because:

  • The medication alters gut bacteria.
  • Your underlying condition (such as IBS-D) fluctuates naturally.
  • You may develop antibiotic-associated diarrhea, including C. diff infection.

Serious Causes of Diarrhea While Taking Xifaxan

Although rare, severe diarrhea may indicate:

C. difficile (Clostridioides difficile) colitis

Symptoms include:

  • Watery diarrhea
  • Fever
  • Abdominal cramping
  • Blood or mucus in stool

This infection can become life-threatening, and antibiotics like Xifaxan can sometimes trigger it.

Lack of response or worsening IBS-D

People taking Xifaxan for IBS-D may temporarily feel worse due to:

  • Gut motility changes
  • Bloating
  • New or altered bowel patterns

Allergic reaction or sensitivity

Diarrhea may accompany:

  • A rash
  • Peripheral edema
  • Trouble breathing

Seek immediate medical attention if this occurs.

Common Side Effects of Xifaxan

While diarrhea is possible, more common side effects include:

  • Bloating
  • Abdominal pain
  • Constipation
  • Nausea
  • Flatulence
  • Headache
  • Fatigue

These are usually mild and temporary.

Less common but reported side effects

  • Muscle spasms
  • Peripheral edema
  • Increased liver enzymes
  • Anemia or low red blood cell count
  • Changes in appetite (loss of appetite or weight gain)

These are not all of the possible side effects of Xifaxan. You should always seek medical advice from your healthcare provider for any questions or concerns about your medical condition or treatment. Read all patient information, medication guides, or drug information sheets that come with this medication. You can also report adverse effects to the Food and Drug Administration at www.fda.gov/medwatch or 1-800-FDA-1088.

When to Seek Medical Attention

Contact a healthcare provider if you experience serious side effects like:

  • Severe diarrhea lasting more than 48–72 hours
  • Bloody or black stools
  • Fever or dehydration
  • Severe abdominal pain
  • Signs of Clostridium difficile (C. diff) infection
  • Worsening symptoms of hepatic encephalopathy
  • Signs of an allergic reaction
  • New swelling or severe fatigue

Why Xifaxan Might Cause Diarrhea

Gut Bacteria Disruption

Even though rifaximin is minimally absorbed, it still affects gut bacteria. This disruption can lead to:

  • Loose stools
  • Increased motility
  • Unpredictable IBS-D symptoms

Underlying IBS-D

Patients taking Xifaxan for the treatment of irritable bowel syndrome may already have diarrhea as their main symptom. The medication may not immediately control episodes.

Antibiotic Effects

Like other antibiotics, rifaximin can occasionally:

  • Reduce “good” bacteria
  • Allow harmful bacteria to grow
  • Increase risk of antibiotic-associated colitis

Drug interactions

Certain medications increase rifaximin levels, including:

  • Cyclosporine
  • Warfarin
  • P-glycoprotein inhibitors

This may intensify or worsen GI side effects.

Who Is at Higher Risk of Diarrhea on Xifaxan?

You may be at increased risk if you:

  • Have liver disease or hepatic impairment
  • Take immunosuppressants like cyclosporine
  • Have a history of colitis
  • Recently took other antibiotics
  • Have risk factors for C. difficile infection
  • Have unstable IBS-D symptoms
  • What Should You Do If Xifaxan Causes Diarrhea?

Contact your healthcare professional

They may:

  • Adjust your treatment
  • Test for C. difficile
  • Recommend hydration or dietary changes
  • Prescribe supportive medications

Do not take over-the-counter antidiarrheals without medical advice

Some medications may worsen colitis or mask symptoms.

Watch for dangerous symptoms

Bloody stool, fever, inability to keep fluids down, or confusion (in people with ascites or hepatic encephalopathy) requires immediate medical attention.

Can You Prevent Diarrhea While Taking Xifaxan?

  • Avoid unnecessary foods, medications, and supplements that irritate the GI tract.
  • Stay hydrated.
  • Follow directions in the prescribing information.
  • Take the medication for the full prescribed course.
  • Monitor for side effects of Xifaxan and report concerns early.

Is Xifaxan Available Over-the-Counter?

No. Xifaxan is a prescription drug and is not available over the counter. Because it treats complex GI conditions, dosing must be monitored by a healthcare provider.

Bottom Line

Yes, Xifaxan can cause diarrhea, although it is not one of the most common side effects. Most cases are mild, but persistent or severe diarrhea may signal antibiotic-associated colitis or C. difficile, especially in vulnerable individuals. Always report concerning symptoms to a healthcare professional.

FAQs

Is diarrhea a common side effect of Xifaxan?
Not common, but it can occur, particularly in people with IBS-D or underlying GI sensitivity.

Can Xifaxan worsen IBS-D before improving it?
Some patients experience fluctuating symptoms before improvement.

Does Xifaxan kill good gut bacteria?
Yes, like any antibiotic, it can disrupt the microbiome and potentially cause diarrhea.

Can you take Xifaxan if you are pregnant or breastfeeding? It’s not known whether it’s safe to take Xifaxan during pregnancy or while breastfeeding. If you’re pregnant, breastfeeding, or planning for either, talk with your doctor before taking Xifaxan.

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