Rifaximin (Xifaxan®)

Author: OncoLink Team
Last Reviewed: October 30, 2023

Pronounce: rif-AX-i-min

Classification: Antibacterial

About: Rifaximin (Xifaxan®)

This medication works by stopping bacterial protein synthesis. By doing this, it stops the growth of bacteria that can cause diarrhea.

How to Take Rifaximin (Xifaxan ®)

This medication comes in a tablet form to be taken by mouth. It can be taken with or without food. Your provider will tell you your dose and how often you should take the medication. Make sure to take all of your doses, even if you are feeling better to ensure the medication has full effect. It is important to make sure you are taking the correct amount of medication every time. Before every dose, check that what you are taking matches what you have been prescribed.

You should not take this medication if you have a fever or mucous or blood in your stool without first checking with your provider. You may need to have your stool tested for an infection before taking this medication. Ttell your provider if you are having diarrhea prior to taking this medication. In some cases, this medication can cause another bacterial infection called clostridium difficilem (C.diff). If your diarrhea gets worse, you should tell your provider so your stool can be tested for this bacteria.

If you have a history of liver problems, you should tell your provider as liver problems can change the effectiveness of this medication. The blood levels of this medication can be affected by certain foods and medications, so they should be avoided. These include: amiodarone, carvedilol, clarithromycin, cyclosporine, erythromycin, ketoconazole, ritonavir, quinidine, warfarin, and verapamil, among others. Be sure to tell your healthcare provider about all medications and supplements you take.

Storage and Handling

Store this medication at room temperature. Keep this medication out of reach of children and pets. Dispose of any unused medication safely.

Where do I get this medication?

This medication is available by prescription through a retail/mail order pharmacy. Your oncology team will work with your prescription drug plan to identify an in-network retail/mail order pharmacy for medication distribution. You can work with your doctor’s office if this medication needs prior authorization.

Insurance Information

Rifaximin may be covered under your prescription drug plan. Patient assistance may be available to qualifying individuals without prescription drug coverage.  Co-pay cards, which reduce the patient co-pay responsibility for eligible commercially (non-government sponsored) insured patients,  may also be  available. Your care team can help you find these resources if they are available. 

Possible Side Effects of Rifaximin

This medication is given to manage and/or prevent the side effects of your cancer treatment. If you are having side effects from this medication, you should talk to your team about if this medication is necessary for your treatment or if there are other options to help manage the side effect this medication is treating. These are some of the most common side effects:

Swelling (Edema)

This medication can cause a buildup of fluid and swelling (edema) in the face, especially around the eyes, and extremities (arms and legs). It may also cause a buildup of fluid and swelling in the lower abdomen (belly). This can be a sign of other problems, so be sure to report any abnormal swelling to your healthcare team for further testing.


Nausea can be a side effect of this medication. Talk to your healthcare team so they can prescribe medications to help you manage nausea and vomiting. In addition, dietary changes may help. Avoid things that may worsen the symptoms, such as heavy or greasy/fatty, spicy or acidic foods (lemons, tomatoes, oranges). Try saltines, or ginger ale to lessen symptoms.

Call your oncology care team if you are unable to keep fluids down for more than 12 hours or if you feel lightheaded or dizzy at any time.


Fatigue can occur with this medication and you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help with fatigue. Talk to your healthcare team for helpful tips on dealing with this side effect.

Reproductive Concerns

You should talk with your provider before becoming pregnant or fathering a child while on this medication. You should talk with your healthcare team before breastfeeding while receiving this medication.