Xifaxan Medicare Coverage 2026: Costs, Appeals, and Financial Assistance Guide

Table of Contents#

1. What Is Xifaxan & Who Needs It?
2. Does Medicare Cover Xifaxan?
3. How Much Does Xifaxan Cost With Medicare?
4. Step-by-Step Appeal Process for Denied Xifaxan Coverage
5. Financial Assistance Programs for Xifaxan for Medicare Beneficiaries
6. Final Tips to Maximize Xifaxan Coverage
7. References

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What Is Xifaxan & Who Needs It?#

Xifaxan is the brand-name version of the prescription antibiotic rifaximin. Unlike most antibiotics, it is not absorbed into the bloodstream, so it works exclusively in the gastrointestinal tract with minimal side effects. It is FDA-approved for three primary uses:

• Treatment of travelers' diarrhea caused by noninvasive strains of E. coli
• Reduction of risk for overt hepatic encephalopathy recurrence in adults with liver cirrhosis
• Short-term treatment of IBS-D in adults

Xifaxan is also commonly prescribed off-label for small intestinal bacterial overgrowth (SIBO), though Medicare coverage for off-label uses varies by plan and may require additional documentation.

As of 2026, no generic version of Xifaxan is available in the U.S. The FDA granted tentative approval to Amneal Pharmaceuticals for generic rifaximin tablets in January 2025, but Bausch Health's patent on Xifaxan does not expire until 2029, meaning a generic is not expected to reach the market before then. This patent protection is the primary driver of its high retail cost.

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Does Medicare Cover Xifaxan?#

Coverage for Xifaxan depends on which part of Medicare you are enrolled in:

1. Medicare Part A (Inpatient Coverage)#

Xifaxan is only covered under Part A if it is administered to you during an inpatient stay at a hospital or skilled nursing facility, as part of your formal treatment plan. You will only be responsible for your Part A deductible ($1,736 per benefit period in 2026) and no additional costs for the medication.

2. Medicare Part B (Outpatient Coverage)#

Coverage under Part B is extremely rare, and only applies if Xifaxan is administered in an outpatient clinic setting for a Part B-eligible condition (e.g., post-organ transplant infection prevention). Prior authorization is always required for Part B coverage of Xifaxan.

3. Medicare Part D (Standalone Prescription Drug Plan)#

This is the primary source of coverage for Xifaxan for most beneficiaries. According to the manufacturer, 100% of Medicare Part D plans include Xifaxan on their formularies for FDA-approved indications. It is almost always classified as a Tier 3 (preferred brand) or Tier 4 (non-preferred brand) medication. All plans covering Xifaxan require prior authorization, meaning your doctor must submit proof that:

• You have an FDA-approved diagnosis for Xifaxan
• You tried and failed cheaper first-line treatments for your condition (e.g., loperamide for IBS-D, metronidazole for SIBO)

4. Medicare Advantage (Part C)#

All Medicare Advantage plans are required to offer at least the same prescription coverage as Original Medicare Part D. Coverage rules for Xifaxan are identical to Part D, but some MA plans may have lower copays or less restrictive prior authorization rules than standalone Part D plans. You can check your MA plan’s formulary on your plan’s website to confirm coverage.

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How Much Does Xifaxan Cost With Medicare?#

Your out-of-pocket cost for Xifaxan depends on which phase of Part D coverage you are in. Thanks to the Inflation Reduction Act, the Part D coverage gap (donut hole) was eliminated in 2025, and annual out-of-pocket costs are now capped. The 2026 numbers are below:

If you qualify for Medicare Extra Help (Low-Income Subsidy, LIS), you will pay $0–$11.20 per 30-day supply of Xifaxan, with no deductible costs. The Inflation Reduction Act caps annual out-of-pocket Part D costs at $2,100 in 2026 (up from$2,000 in 2025), eliminating the high costs that previously burdened Xifaxan users in the coverage gap.

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Step-by-Step Appeal Process for Denied Xifaxan Coverage#

If your Medicare plan denies coverage for Xifaxan, you have the right to appeal the decision within 60 days of receiving your denial letter:

1. Request a formal coverage determination from your plan: You can submit this request online, over the phone, or by mail using the form included in your denial letter.
2. Gather medical evidence from your doctor: Ask your provider to submit a letter of medical necessity, documentation of your diagnosis, and proof that you tried and failed all cheaper alternative treatments required by your plan.
3. Choose between standard or expedited appeal: Standard appeals get a decision within 7 calendar days. If waiting 7 days would harm your health, request an expedited appeal, which will get a decision within 72 hours.
4. Request independent review if your first appeal is denied: If your plan upholds the denial, you can request a redetermination from an independent third-party reviewer unassociated with your plan, within 60 days of the first denial decision.
5. Higher level appeals if needed: If the independent reviewer upholds the denial, you can request a hearing with the Office of Medicare Hearings and Appeals (if the amount you are contesting is at least $200 in 2026), followed by a review by the Medicare Appeals Council, and finally federal court for high-value claims.

Tip: Ask your doctor to request a 30-day temporary supply of Xifaxan from your plan while your appeal is processing, to avoid gaps in treatment.

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Financial Assistance Programs for Xifaxan for Medicare Beneficiaries#

If you cannot afford your out-of-pocket costs for Xifaxan, use these eligible programs for Medicare enrollees:

1. Bausch Health Patient Assistance Program: Xifaxan’s manufacturer offers free Xifaxan for up to 12 months for eligible beneficiaries. Eligibility requirements: U.S. resident, no prescription coverage for Xifaxan (or denied coverage with appeals exhausted), household income at or below 300% of the federal poverty level. You must also demonstrate that you do not have coverage through Medicare Part D, Medicaid, or other government insurance (Medicare Part D enrollees denied LIS may be evaluated on a case-by-case basis). Call 1-833-862-8727 or visit bauschhealthpap.com to apply.
2. Medicare Extra Help (LIS): This federal program covers most prescription costs for low-income Medicare beneficiaries. Eligibility: Household income below 150% of the federal poverty level, assets below $17,600 for individuals /$35,130 for couples in 2026. You can apply via the Social Security Administration website.
3. State Pharmaceutical Assistance Programs (SPAPs): Most U.S. states offer subsidized prescription coverage for low-income Medicare beneficiaries. SPAP contributions may count toward your Part D out-of-pocket limit. Eligibility and benefits vary by state; you can find your state’s program via the Medicare plan compare tool.
4. Nonprofit Patient Assistance Grants: Organizations including the PAN Foundation and HealthWell Foundation offer grants to cover out-of-pocket Xifaxan costs for people with qualifying diagnoses (IBS-D, cirrhosis, SIBO) and household incomes below 400–500% of the federal poverty level.
5. 90-day mail-order supplies: Most Part D and MA plans offer lower cost-sharing for 90-day supplies of covered medications, so you can save on your annual Xifaxan costs by using mail-order pharmacy options.

Important note: The Xifaxan manufacturer copay savings card is only for people with commercial insurance. Federal law prohibits Medicare, Medicaid, and other government insurance beneficiaries from using this card.

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Final Tips to Maximize Xifaxan Coverage#

1. Check your plan’s formulary every year during Medicare Open Enrollment (October 15–December 7) to confirm Xifaxan is covered, and switch plans if your current plan has high copays or no coverage for Xifaxan.
2. Ask your doctor to submit prior authorization for Xifaxan before you fill your first prescription, to avoid unexpected denials at the pharmacy.
3. Keep copies of all denial letters, doctor’s notes, and prescription receipts to streamline the appeal process if you need it.
4. If you are struggling with costs, reach out to a free Medicare counselor via your State Health Insurance Assistance Program (SHIP) for personalized support.

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References#

1. Centers for Medicare & Medicaid Services. (2026). Medicare Part D Improvements. Retrieved from https://www.cms.gov/priorities/medicare-prescription-drug-affordability/overview/medicare-part-d-improvements
2. Medicare.gov. (2026). How much does Medicare drug coverage cost? Retrieved from https://www.medicare.gov/health-drug-plans/part-d/basics/costs
3. Bausch Health. (2026). Patient Assistance Program. Retrieved from https://www.bauschhealthpap.com/
4. U.S. Food and Drug Administration. (2025). Rifaximin Tablets, 200 mg and 550 mg — Tentative Approval. Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/appletter/2025/214370Orig1s000TAltr.pdf
5. PAN Foundation. (2026). Financial Assistance. Retrieved from https://www.panfoundation.org/
6. Federal Register. (2025). Medicare Appeals; Adjustment to the Amount in Controversy Threshold Amounts for 2026. Retrieved from https://www.federalregister.gov/documents/2025/12/04/2025-21879/medicare-program-medicare-appeals-adjustment-to-the-amount-in-controversy-threshold-amounts-for