Xifaxan costs roughly $3,700 for a 60-tablet supply of the 550 mg strength, making it one of the most expensive branded antibiotics on the U.S. market. The price stays high because of an extensive wall of patent protection, no generic competition, and the drug’s unique clinical role in conditions where few alternatives exist.
A Patent Wall That Blocks Generics Until 2029
The single biggest reason Xifaxan remains expensive is that no generic version is available in the United States. Bausch Health (formerly Valeant Pharmaceuticals), the company that markets Xifaxan through its subsidiary Salix, holds more than 20 patents on the 550 mg tablet. While the earliest of these patents began expiring in 2025, the majority don’t expire until July 2029. This staggered patent strategy is sometimes called a “patent thicket.” Each patent covers a slightly different aspect of the drug’s formulation, manufacturing process, or clinical use, and a generic manufacturer would need to navigate all of them to bring a competitor to market.
The FDA has granted tentative approval to at least one generic version of rifaximin, the active ingredient in Xifaxan. But tentative approval only means the generic meets safety and effectiveness standards. The manufacturer still cannot launch and sell the product until the relevant patents expire or are successfully challenged in court. So for the foreseeable future, Bausch Health faces no price competition on its bestselling product.
Limited Alternatives for the Conditions It Treats
Xifaxan is FDA-approved for three conditions: traveler’s diarrhea, irritable bowel syndrome with diarrhea (IBS-D), and hepatic encephalopathy, a serious brain complication of liver disease. For traveler’s diarrhea, cheaper antibiotics like ciprofloxacin or azithromycin work well, and most insurers require you to try one of those first. But for hepatic encephalopathy and IBS-D, Xifaxan fills a role that’s harder to replace.
In hepatic encephalopathy, Xifaxan significantly reduces hospital readmissions. Patients taking rifaximin alongside lactulose had a 30-day rehospitalization rate of about 7.4% to 9.3%, compared with 11% to 13% for patients on lactulose alone. Over a full year, the gap widens further: patients on rifaximin averaged roughly 0.9 hospitalizations per year versus 1.4 to 1.6 for those without it. Each avoided hospitalization can cost tens of thousands of dollars, which gives Bausch Health leverage to argue the drug’s price is justified by the savings elsewhere in the healthcare system.
For IBS-D, Xifaxan is one of the few targeted treatments. A short 14-day course can provide weeks or months of symptom relief for some patients, though symptoms often return and repeat courses may be needed. That cycle of retreatment adds to the cumulative cost.
How the Drug Works (and Why That Matters for Price)
Xifaxan is unusual because less than 0.4% of the drug gets absorbed into your bloodstream. About 97% of each dose passes through the gut unchanged and leaves the body in stool. This means it acts almost entirely within the intestines, which reduces the risk of systemic side effects and drug interactions. That localized action is part of what makes it effective for gut-specific conditions, and it’s also part of what the patents protect. Replicating that behavior in a generic isn’t as straightforward as copying a pill that simply dissolves into the blood.
Insurance Hurdles Add to the Burden
Most insurance plans require prior authorization before covering Xifaxan, which means your doctor needs to submit paperwork proving the drug is medically necessary. The requirements vary by condition. For traveler’s diarrhea, insurers typically require proof that you’ve tried and failed a cheaper antibiotic first. For hepatic encephalopathy, you generally need to show that lactulose alone isn’t controlling symptoms. For IBS-D, the bar is even higher: UnitedHealthcare, for example, requires that you’ve tried and failed both a tricyclic antidepressant and another IBS medication before Xifaxan gets covered.
Even with insurance approval, your copay can be substantial depending on your plan’s formulary tier. Without insurance, you’re looking at $3,700 to nearly $4,000 at most pharmacies for a single month’s supply of the 550 mg dose.
Ways to Lower the Cost
Bausch Health runs a patient assistance program for people who can’t afford the drug. To qualify, your annual household income must be at or below 300% of the federal poverty level. For a single person in 2025, that’s roughly $47,000 per year. If you qualify, you may receive the medication at no cost.
Manufacturer copay cards are sometimes available for commercially insured patients and can reduce out-of-pocket costs significantly, though they typically don’t apply to government insurance like Medicare or Medicaid. Specialty pharmacies and discount programs like GoodRx may also offer lower prices than standard retail, but the savings on a drug this expensive tend to be modest without insurance.
The most meaningful price relief will likely come when the last key patents expire in 2029 and generic manufacturers can finally enter the market. Based on patterns with other branded drugs, generic rifaximin could cost a fraction of the current price within a year or two of launch. Until then, the combination of patent exclusivity, limited alternatives, and demonstrated clinical value keeps Xifaxan priced where it is.