Xifaxan (rifaximin) is one of the most expensive commonly prescribed antibiotics in the United States, with a retail price around $3,100 for a standard 42-tablet supply of the 550mg dose. Even with discount coupons, you’re looking at roughly $2,200 to $2,800 out of pocket. But there are several realistic ways to bring that number down significantly, depending on your insurance situation and how flexible your options are.
Use Pharmacy Discount Coupons
If you’re paying cash or have a high-deductible plan, free discount coupons from sites like GoodRx can shave several hundred dollars off the retail price. For 42 tablets of Xifaxan 550mg, prices with a coupon range from about $2,184 at Hy-Vee to $2,841 at Costco. CVS and Target tend to land around $2,553, while Walmart sits near $2,659. These aren’t small differences. Shopping around between pharmacies in your area can save you $500 or more on the same prescription.
That said, even the lowest coupon price is still north of $2,000, so this approach works best as a complement to other strategies rather than a standalone solution.
Navigate Insurance Prior Authorization
Most insurance plans cover Xifaxan but require prior authorization, meaning your doctor has to submit paperwork proving you meet specific criteria before the plan will pay. The requirements vary by diagnosis, and understanding them can help you and your doctor build a stronger case.
For IBS with diarrhea, insurers like UnitedHealthcare typically require that you’ve already tried and failed (or can’t tolerate) a tricyclic antidepressant such as amitriptyline, plus either tried eluxadoline (Viberzi) or have a history of substance abuse risk that makes Viberzi inappropriate. For hepatic encephalopathy, you generally need to show that lactulose alone isn’t controlling your symptoms and that Xifaxan is being added on top of it. For traveler’s diarrhea, you’ll need documentation that a standard antibiotic like ciprofloxacin or azithromycin didn’t work or wasn’t an option.
The key takeaway: if your doctor prescribes Xifaxan and your insurer denies it, look at exactly what the plan requires. In many cases, the denial happens because the prior authorization form didn’t document a previous trial of a cheaper medication. Your doctor’s office can often resubmit with the right documentation and get approval on appeal.
Medicare Part D Coverage
Medicare Part D plans can cover Xifaxan, though your out-of-pocket costs depend on the plan’s formulary tier and where you are in the coverage cycle. In 2026, the yearly Part D deductible is $615. After you meet that, you typically pay 25% of the drug’s cost until your out-of-pocket spending hits $2,100. Once you cross that $2,100 threshold, the plan covers the full cost for the rest of the year.
Because Xifaxan is so expensive, a single fill can push you through the deductible and into the catastrophic coverage phase quickly. If you need ongoing treatment (as many people with hepatic encephalopathy do), your costs for the rest of the calendar year drop to zero after that initial hit. It’s worth timing your fills strategically and checking whether your specific Part D plan places Xifaxan on a specialty tier, which could change your cost-sharing percentage.
International Pharmacies
The price gap between the U.S. and international markets is enormous. According to PharmacyChecker, verified international online pharmacies sell Xifaxan 550mg for about $8.83 per tablet, compared to roughly $56 to $59 per tablet at U.S. pharmacies. That’s an 85% difference. For a 42-tablet course, that works out to around $370 internationally versus over $2,400 domestically.
Ordering prescription drugs from outside the U.S. occupies a legal gray area. The FDA technically prohibits personal importation, but in practice the agency generally exercises discretion for individuals buying a 90-day supply or less of medication for personal use. If you go this route, stick to pharmacies verified by PharmacyChecker or the Canadian International Pharmacy Association, and avoid any site that doesn’t require a valid prescription.
The Manufacturer Savings Program
Salix Pharmaceuticals, which makes Xifaxan, offers a patient savings card that can reduce copays for people with commercial insurance. These programs typically cap your copay at a set dollar amount per fill. They don’t help if you’re uninsured or on a government plan like Medicare or Medicaid, but for commercially insured patients facing a high specialty-tier copay, the savings card can cut costs substantially. Check the Xifaxan website directly for current terms, as the specifics change periodically.
Generic Rifaximin Is Coming in 2028
Bausch Health (which owns Salix) settled patent litigation with three generic manufacturers: Sun, Actavis, and Sandoz. All three received non-exclusive licenses to sell generic rifaximin in the U.S. starting January 1, 2028. If any generic company manages to get approval and launch before that date, the settlement allows the others to enter the market early as well.
Generic entry typically drops a brand-name drug’s price by 80% or more within the first year or two, especially when multiple manufacturers compete. If you can manage your condition with alternative treatments until then, the cost picture will look dramatically different in a couple of years. For people with hepatic encephalopathy who need Xifaxan long-term and can’t switch, this timeline is worth planning around with your doctor.
Lower-Cost Alternatives Worth Discussing
Depending on your diagnosis, cheaper medications may address the same underlying problem. For IBS with diarrhea, options include tricyclic antidepressants like amitriptyline (pennies per day as a generic), dicyclomine, hyoscyamine, or loperamide for symptom control. Linzess works differently but is another prescription option, though it’s also brand-name and not cheap. For hepatic encephalopathy, lactulose is the first-line treatment and costs a fraction of Xifaxan. Neomycin is an older generic antibiotic sometimes used as an alternative, though it carries more side-effect risk with long-term use.
None of these are direct substitutes for rifaximin, and for some patients, Xifaxan is genuinely the best or only effective option. But if cost is the primary barrier keeping you from treating your condition at all, a less expensive alternative that partially controls your symptoms is better than no treatment. Bring up the cost issue directly with your doctor, since many prescribers aren’t aware of what patients actually pay and can adjust the plan accordingly.