Xifaxan is an antibiotic that fights bacterial infection only in the intestines.

Rifaximin works differently from other antibiotics because it passes through your stomach and into your intestines without being absorbed into your blood stream. Because rifaximin treats only the intestinal tract, it will not treat infections of other parts of the body.

Xifaxan is used to treat travelers' diarrhea caused by Escherichia coli (E. coli) in adults and children who are at least 12 years old. Most people get this infection by eating food or drinking fluids that have been contaminated with the E. coli bacteria.

Xifaxan is also used to treat irritable bowel syndrome (IBS) in adults whose main symptom is diarrhea.

Xifaxan is also used to lower the risk of a decline in brain function in adults with liver failure. Brain function can be affected when the liver stops working and cannot remove toxic substances from the body.

You should not use take Xifaxan if you are allergic to rifaximin or medications such as rifabutin (Mycobutin), rifampin (Rifater, Rifadin, Rifamate), or rifapentine (Priftin).

Before you take Xifaxan, tell your doctor if you have severe liver disease, diarrhea with fever, or diarrhea that is watery or has blood in it.

Take Xifaxan for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Rifaximin will not treat a viral infection such as the common cold or flu, or any form of diarrhea that is caused by a virus. Call your doctor if your symptoms do not improve after 24 hours, or if they get worse while taking this medicine. Xifaxan does not treat all bacterial forms of traveler's diarrhea.

Take Xifaxan exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets.

You may take this medicine with or without food.

For travelers' diarrhea, Xifaxan is usually taken for only 3 days. For IBS, it is usually taken for 2 weeks at a time. Follow your doctor's dosing instructions very carefully.

Use this medicine for the full prescribed length of time, even if your symptoms quickly improve. Skipping doses can increase your risk of infection that is resistant to medication. Xifaxan will not treat a viral infection such as the flu or a common cold.

Do not share this medicine with another person, even if they have the same symptoms you have.

Call your doctor if your symptoms do not improve after 24 to 48 hours, or if they get worse while using this medicine.

Xifaxan does not treat all bacterial forms of travelers' diarrhea.

Store at room temperature away from moisture and heat.

Usual Adult Dose for Traveler's Diarrhea:

200 mg orally 3 times a day for 3 days

Comments:
-Should not use in patients with diarrhea complicated by fever and/or blood in the stool or diarrhea caused by pathogens other than Escherichia coli

Use: For the treatment of travelers' diarrhea due to noninvasive strains of E coli

Usual Adult Dose for Hepatic Encephalopathy:

550 mg orally twice a day

Comments:
-In trials, lactulose was used concomitantly in 91% of patients; differences in treatment effect of patients not using concomitant lactulose could not be assessed.

Use: For reduction in risk of overt hepatic encephalopathy recurrence

Usual Adult Dose for Irritable Bowel Syndrome:

550 mg orally 3 times a day for 14 days

Comments:
-If symptoms recur, patients can be retreated up to 2 times with the same dose regimen.

Use: For the treatment of irritable bowel syndrome with diarrhea

Usual Pediatric Dose for Traveler's Diarrhea:

12 years or older: 200 mg orally 3 times a day for 3 days

Comments:
-Should not use in patients with diarrhea complicated by fever and/or blood in the stool or diarrhea caused by pathogens other than E coli

Use: For the treatment of travelers' diarrhea due to noninvasive strains of E coli

You should not take Xifaxan if you are allergic to rifaximin, rifabutin, rifampin, or rifapentine.

To make sure Xifaxan is safe for you, tell your doctor if you have:

• liver disease;

• diarrhea with a fever; or

• watery or bloody diarrhea.

Tell your doctor if you are pregnant or breastfeeding.

Xifaxan should not be given to a child younger than 12 years old.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, call your doctor before using anti-diarrhea medicine.

Get emergency medical help if you have signs of an allergic reaction to Xifaxan: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

• severe stomach pain, diarrhea that is watery or bloody (even if it occurs months after your last dose);

• fever; or

• fluid build-up around the stomach - rapid weight gain, stomach pain and bloating, trouble breathing while lying down.

Common Xifaxan side effects may include:

• swelling in your hands or feet;

• nausea;

• headache, dizziness;

• tiredness; or

• abnormal liver function tests.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor about all your other medicines, especially:

• cyclosporine;

• ketoconazole;

• warfarin (Coumadin, Jantoven);

• an antibiotic - clarithromycin, erythromycin;

• antiviral medicine - ritonavir, saquinavir; or

• heart or blood pressure medicine - amiodarone, quinidine, verapamil.

This list is not complete. Other drugs may interact with rifaximin, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.