Xifaxan and Other Antibiotics

Reviewed by: HU Medical Review Board | Last reviewed: March 2023

One of the factors that is believed to cause or trigger irritable bowel syndrome (IBS) is the overgrowth of harmful bacteria in the intestines. Because of this, gut-specific antibiotics are often prescribed for patients with IBS, particularly those patients who complain of gas, bloating symptoms, abdominal pain, and diarrhea.1,2

Antibiotics are medicines that fight bacterial infections. They either kill bacteria or keep them from reproducing.3

The most studied antibiotic in IBS treatment is rifaximin, brand name Xifaxan. Xifaxan is minimally absorbed by the gastrointestinal tract, which allows more of the drug to remain in the intestines. Also, this means there is less of the drug in the rest of the body. Xifaxan does not seem to significantly alter the natural microflora (good bacteria) in the gut, and it does not cause diarrhea like some antibiotics may.1

What is Xifaxan?

Xifaxan is a prescription drug used in adults with IBS with diarrhea (IBS-D). People treated for two weeks with Xifaxan may get 6 to 24 weeks of relief from IBS-D symptoms, including abdominal pain and diarrhea. On average, people in a clinical trial with Xifaxan experienced 10 weeks of relief. People can be retreated with Xifaxan up to 2 times if symptoms come back.4

How to take Xifaxan

Xifaxan tablets can be taken with or without food. It is important to take the entire course of treatment – 3 tablets a day for 14 consecutive days – to experience the effectiveness of the treatment. Treatment should not be stopped even if the person starts to feel relief from thier IBS symptoms. If a dose is missed, it should be taken as soon as it is remembered. But if it is time for the next dose, the missed dose should be skipped. Double doses to make up for the forgotten dose are not recommended.3,4

Before taking Xifaxan, people should discuss with their doctor all drugs and supplements they are currently taking, especially cyclosporine or any other antibiotics. People who are allergic to rifaximin should not take Xifaxan. People who are pregnant, planning to become pregnant, or breastfeeding, should discuss their condition with their doctor before taking Xifaxan as it is unknown whether the drug might harm the baby.3,4

Xifaxan side effects

The most common side effects experienced by people taking Xifaxan are swelling, dizziness, nausea, headache, fatigue, and an increase in liver enzymes (specifically Alanine aminotransferase, or ALT).

These are not all the possible side effects of Xifaxan. Talk to your doctor about what to expect or if you experience any changes that concern you during treatment with Xifaxan.

Other antibiotics for IBS

There have been some studies that have shown another antibiotic, neomycin, to be effective in treating IBS-D. However, there are more side effects with neomycin. Systemic antibiotics, those that are absorbed and circulate throughout the body, have not been well studied as a treatment for IBS.1

Other IBS treatments

Often, people with IBS have to try several treatment options to find what works best for them. Many people may find that a combination of treatment approaches helps manage their symptoms. In addition to antibiotics, other treatment options for IBS include adding exercise, making dietary changes, adding fiber, using probiotics, getting counseling, or trying complementary or alternative medicine.

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