Rifaximin (Generic Xifaxan)

What is generic Xifaxan?

Generic Xifaxan is a tablet that contains rifaximin, the antibiotic in Xifaxan. Rifagut, made by Sun Pharma, and Rifaxiheal, made by Healing Pharma, contain the same active ingredient as Xifaxan; both are made and licensed in India. In the US, rifaximin is prescribed for irritable bowel syndrome with diarrhea (IBS-D), to lower the risk of hepatic encephalopathy coming back, and for some cases of travelers' diarrhea.

Rifaximin works differently from most antibiotics. Very little of it is absorbed into the bloodstream, so it acts mainly on bacteria inside the intestine, where it stops them from making the RNA they need to grow.

Is there a generic Xifaxan in the US?

Xifaxan is marketed in the US by Salix Pharmaceuticals, a division of Bausch Health. The FDA's Orange Book lists 19 patents for Xifaxan 550 mg, the last of them running to 2029. Patents and legal settlements can delay the date an approved generic actually reaches pharmacies, and the brand is expensive without insurance, so ask your pharmacist whether a US generic is stocked and covered by your plan.

Is Rifagut the same as Xifaxan?

Rifagut and Rifaxiheal contain the same medicine as Xifaxan, but the strengths on offer differ.

The 400 mg tablets have no US equivalent. Do not swap a 400 mg tablet for a 550 mg tablet, or the other way around, unless your doctor rewrites the dose, because the total daily amount changes.

Which rifaximin tablets are available here?

Prices can change. Shipping to the USA is a flat $30, and free on orders of $199 or more. For other antibiotics we carry, see our antibiotic category.

What doses are on the US Xifaxan label?

The US prescribing information for Xifaxan lists three uses, each with its own dose. Your own prescription may differ, so follow it and the pack leaflet.

Hepatic encephalopathy is confusion, drowsiness and personality change that happens when a damaged liver cannot clear toxins made in the gut. In the main study behind this use, most people also took lactulose. For more on the IBS-D course and what happens if symptoms come back, read our guide to rifaximin for IBS-D.

How do I choose the right strength?

• IBS-D or hepatic encephalopathy: the US regimens use the 550 mg tablet. One 14-day IBS-D course uses 42 tablets, and twice-daily treatment for hepatic encephalopathy uses about 60 tablets a month.
• Travelers' diarrhea: the US regimen uses 200 mg tablets, nine in total for a 3-day course.
• 400 mg tablets: choose these only if your doctor has prescribed a regimen based on 400 mg.

Rifaximin is not a treatment for every bout of diarrhea. It should not be used for diarrhea with fever or blood in the stool, and it is not effective for travelers' diarrhea caused by Campylobacter jejuni. The CDC does not recommend antibiotics for mild travelers' diarrhea and notes that replacing lost fluids is key to treating any case.

How do you take rifaximin?

• Take it with or without food, at about the same times each day.
• For IBS-D or travelers' diarrhea, take the full course as prescribed even if you feel better early, unless your doctor tells you to stop.
• For hepatic encephalopathy, keep taking it until your doctor tells you to stop.
• If you miss a dose, take it when you remember, unless the next dose is nearly due. Never take two doses together.
• If travelers' diarrhea gets worse or lasts longer than 24 to 48 hours, stop and see a doctor.

MedlinePlus has a plain-language patient guide to rifaximin if you want more detail.

What are the side effects of rifaximin?

In the US studies, side effects depended on the condition being treated:

• IBS-D: nausea and a rise in the liver enzyme ALT, each in about 2 in 100 people, compared with about 1 in 100 on a placebo.
• Travelers' diarrhea: headache, in about 10 in 100 people, close to the rate on a placebo.
• Hepatic encephalopathy: swelling of the legs or ankles, nausea, dizziness, tiredness and fluid build-up in the abdomen. Many of these were also common in people taking a placebo.

C. diff warning: like nearly all antibiotics, rifaximin can let Clostridioides difficile, a bacterium that causes bowel inflammation ranging from mild to life-threatening, overgrow in the gut. Call your doctor right away if you get watery or bloody diarrhea, stomach cramps or fever while taking rifaximin or even two or more months after your last dose. Get emergency help for hives, swelling of the face, lips or throat, or trouble breathing or swallowing.

Who should not take rifaximin?

• People allergic to rifaximin, to other rifamycin antibiotics such as rifampin (rifampicin) or rifabutin, or to any tablet ingredient.
• Anyone with diarrhea plus fever or blood in the stool.
• Children outside the labeled ages: the US label covers travelers' diarrhea from age 12, and IBS-D and hepatic encephalopathy in adults only.

Talk to your doctor first if you have severe liver disease (Child-Pugh C), take cyclosporine or other medicines that block P-glycoprotein, which can raise rifaximin levels sharply, or take warfarin, because your INR may need closer checks. Animal studies suggest possible harm to an unborn baby, so tell your doctor if you are pregnant, planning a pregnancy or breastfeeding.

Frequently asked questions

Can I take rifaximin 400 mg instead of 550 mg?

Only if your doctor changes the prescription. Three 400 mg tablets a day give 1,200 mg, while three 550 mg tablets give 1,650 mg, so the two are not interchangeable.

Can I repeat rifaximin if my IBS-D comes back?

The US label allows the 14-day course to be repeated up to two more times in people whose symptoms return. Your doctor decides whether a repeat course is right for you.

Can rifaximin prevent travelers' diarrhea?

The US label covers treatment, not prevention. The CDC does not recommend preventive antibiotics for most travelers, so ask a travel clinic before your trip.

Do I need lactulose with rifaximin for hepatic encephalopathy?

Most people in the main US study took both, and the label says the effect of rifaximin without lactulose could not be assessed. Your liver specialist will decide what combination suits you.

How long does delivery take?

Product pages state delivery in about 6 to 15 days to the USA, and customs checks can add delays.

This article gives general information and does not replace advice from your doctor or pharmacist. Rifaximin is a prescription medicine and should be used only as prescribed for your own condition. If you develop severe or bloody diarrhea, high fever or confusion, seek medical care promptly.