Will Antibiotics Like Xifaxan Help Bloating and Small Intestinal Bacterial Overgrowth (SIBO)?

If you experience abdominal bloating and cramping, you’re not alone. And, often, the cause of these symptoms isn’t clear. Certain foods can trigger bloating and cramping for some people. Sometimes symptoms are caused by an underlying medical condition, like irritable bowel syndrome (IBS) or small intestinal bacterial overgrowth (SIBO). 

SIBO and IBS often go undiagnosed. But, if you have a confirmed diagnosis, an antibiotic like Xifaxan (rifaximin) may help. Xifaxan is also a treatment for travelers’ diarrhea and for some complications of liver disease.

What is Xifaxan (rifaximin)?

Xifaxan is an antibiotic that helps ease gastrointestinal symptoms, such as diarrhea related to IBS or SIBO. Xifaxan works by reducing harmful bacteria in the gut to help rebalance the gut microbiome. It’s unique in that it mostly stays in the intestine (rather than getting absorbed into the bloodstream), which helps decrease side effects. 

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Healthcare professionals often prescribe Xifaxan for a 2-week period to treat symptoms related to IBS or SIBO. It’s FDA-approved for IBS-related diarrhea, but it’s an “off-label” use for SIBO.

What is small intestinal bacterial overgrowth (SIBO)?

SIBO is a disruption of normal bacteria in the small intestine. Symptoms include abdominal pain, gas, and bloating. SIBO often goes underdiagnosed. There’s growing awareness of the condition, but there’s still a lot that the scientific community doesn’t fully understand about SIBO. 

Causes of SIBO may include:

• A decreased production of stomach acid

• Medication side effects (like proton pump inhibitors, antibiotics, or steroids)

• A slow-moving intestine (such as from gastroparesis)

Treatment for SIBO involves dietary changes — like avoiding certain foods or eating a low-FODMAP diet — as well as a 2-week course of Xifaxan.

Will Xifaxan help SIBO?

Research has shown that Xifaxan can improve SIBO symptoms. In addition to treating harmful gut bacteria, it may also have other effects on the gut, such as decreasing inflammation.

People usually tolerate Xifaxan. But there can be side effects and risks. 

Xifaxan side effects include: 

• Nausea

• Fatigue

• Dizziness

• Muscle spasms

• Headache

• Skin rash or itchiness

In rare cases, this antibiotic can cause disturbed liver function. It can also worsen diarrhea in some people and cause gut infections, like Clostridium difficile. 

How much does Xifaxan cost?

Without insurance, Xifaxan is expensive. The out-of-pocket cost can be over $2,000. Your insurance may cover it for IBS or SIBO symptoms. Your healthcare professional may need to help with a prior authorization.

Can other antibiotics treat SIBO?

Xifaxan is the most studied antibiotic for SIBO. But there’s also limited research on other antibiotics for SIBO. Alternative antibiotics for SIBO include:

• Flagyl (Metronidazole)

• Cipro (Ciprofloxacin)

• Mondoxyne NL (doxycycline) 

• Augmentin (amoxicillin / clavulanate)

If Xifaxan isn’t an option for you, be sure to talk with your healthcare team about whether there are alternative treatment options for SIBO that you can try.

Other causes of gas and bloating

SIBO certainly isn’t the only cause of gas and bloating. These are common symptoms, and it can be hard to figure out the cause. Bloating is caused by a buildup of gas in the stomach or intestines. These gases are produced when gut bacteria break down the food you eat. 

The gut has trillions of microorganisms that help keep you healthy. But when they get out of balance, it can lead to symptoms like abdominal pain, cramping, bloating, and more. Here are a few possible causes. 

Dietary triggers 

Many foods can cause symptoms of bloating. Common examples include:

• Lactose

• Fructose

• Sorbitol

• Carbonated beverages. 

All of these can lead to gas. 

Keeping a food diary can help you find links between what you eat and any symptoms you experience. You may also want to try a low-FODMAP diet. This type of diet helps eliminate foods that can cause increased gas production in the intestines.

Irritable bowel syndrome (IBS)

IBS is a common and frustrating condition that can cause:

• Diarrhea

• Constipation

• Abdominal pain

• Bloating

Healthcare professionals often diagnose IBS based on symptoms and after ruling out more serious causes. 

Treatment for IBS involves dietary changes, relaxation techniques and anxiety management, and probiotic supplements. Sometimes medications are also part of the treatment. Medications may include antibiotics (such as Xifaxan) or medications to help treat symptoms, like diarrhea or constipation.

Celiac disease

Celiac disease is an autoimmune condition where eating gluten leads to gastrointestinal symptoms, inflammation, and damage to the intestines. This can lead to symptoms of diarrhea, gas, and bloating, as well as abdominal pain.

A healthcare professional can diagnose celiac disease with blood tests or tests, like an endoscopy and biopsies of the intestine. The treatment is to avoid foods that contain gluten.

Inflammatory bowel disease (IBD)

Inflammatory bowel disease (IBD), like Crohn’s disease and ulcerative colitis, can also cause bloating. These are autoimmune conditions where the immune system reacts against the lining of the intestines. This leads to many uncomfortable symptoms, like abdominal pain, bloating, and diarrhea. 

Unlike the other conditions on this list, IBD can also cause serious complications, like gastrointestinal bleeding, intestinal blockages, and even colon cancer. Healthcare professionals diagnose IBD with an endoscopy or colonoscopy.

When to see a healthcare professional about bloating

It’s always a good idea to discuss any ongoing symptoms with your primary care provider. Sometimes abdominal bloating can be a sign of a more serious condition, such as IBD or ovarian cancer.

Some abdominal symptoms are more worrying than others, including: 

• Abdominal pain that’s severe or ongoing 

• Abdominal bloating that persists longer than a few days

• Blood in your stool or dark and tarry black stool 

• Unintentional weight loss 

• Vomiting 

• High fevers

• Persistent or worsening heartburn symptoms

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Written by:

Christina Palmer, MD

Christina Palmer, MD, is a board-certified family physician with a special interest in chronic care management, women’s health, mental health, and preventive care. She has over 10 years of experience in primary care research, innovation, and practice.

Edited by:

Alex Eastman, PhD, RN

Alex Eastman, PhD, RN, is a California-based registered nurse and staff medical editor at GoodRx, where he focuses on clinical updates and Latino health.

Reviewed by:

Karen Hovav, MD, FAAP

Karen Hovav, MD, FAAP, has more than 15 years of experience as an attending pediatrician in a variety of clinical settings. She has worked in a large academic center in an urban city, a small community hospital, a private practice, and an urgent care clinic.

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