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rifaximin

Sold as XIFAXAN. Class: Antibiotics. First FDA approval 05/25/2004: 22 years on the US market.

This grade answers one narrow question: how strong is the public evidence and safety record behind this drug, and how clean is its money trail and court record? It is not a verdict on whether the drug is right for you.

B

Score breakdown (76/100)

Safety ×35%
C
Evidence ×25%
C
Regulatory ×15%
A
Money & lawsuits ×15%
C
Options ×10%
A

Safety: 73

Evidence: 63

Regulatory history: 96

Money & lawsuits: 70

Options: 100

What the FDA label says

Approved uses

To reduce the development of drug-resistant bacteria and maintain the effectiveness of XIFAXAN and other antibacterial drugs, XIFAXAN when used to treat infection should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy. XIFAXAN is a rifamycin antibacterial indicated for: • Treatment of travelers’ diarrhea (TD) caused by noninvasive strains of Escherichia coli in adult and pediatric patients 12 years of age and older. ( 1.1 ) • Reduction in risk of overt hepatic encephalopathy (HE) recurrence in adults. ( 1.2 ) • Treatment of irritable bowel syndrome with diarrhea (IBS-D) in adults. ( 1.3 ) Limitations of Use TD: Should not use in patients with diarrhea complicated by fever or blood in the stool or diarrhea due to pathogens other than Escherichia coli. ( 1.1, 5.1 ) 1.1 Travelers’ Diarrhea XIFAXAN is indicated for the treatment of travelers’ diarrhea (TD) ca...

Contraindications

is contraindicated in patients with a hypersensitivity to rifaximin, any of the rifamycin antimicrobial agents, or any of the components in XIFAXAN. Hypersensitivity reactions have included exfoliative dermatitis, angioneurotic edema, and anaphylaxis [see Adverse Reactions ( 6.2 )] . History of hypersensitivity to rifaximin, rifamycin antimicrobial agents, or any of the components of XIFAXAN. ( 4) )

Warnings and precautions

• Travelers’ Diarrhea Not Caused by E. coli : XIFAXAN was not effective in diarrhea complicated by fever and/or blood in the stool or diarrhea due to pathogens other than E. coli . If diarrhea symptoms get worse or persist for more than 24 to 48 hours, discontinue XIFAXAN and consider alternative antibiotics. ( 5.1 ) • Clostridium difficile -Associated Diarrhea: Evaluate if diarrhea occurs after therapy or does not improve or worsens during therapy. ( 5.2 ) • Hepatic Impairment: Use with caution in patients with severe (Child-Pugh Class C) hepatic impairment. ( 5.4 , 8.7 ) • Concomitant P-glycoprotein (P-gp) inhibitors (e.g., cyclosporine): Caution should be exercised when concomitant use of XIFAXAN and a P-glycoprotein inhibitor is needed. ( 5.5, 7.1 ) 5.1 Travelers’ Diarrhea Not Caused by Escherichia coli XIFAXAN was not found to be effective in patients with diarrhea complicated by fever and/or blood in the stool or diarrhea due to pathogens other than Escherichia coli. Discontinue XIFAXAN if diarrhea symptoms get worse or persist more than 24 to 48 hours and alternative antibiotic therapy should be considered. XIFAXAN is not effective in cases of travelers’ diarrhea due to Camp...

Adverse reactions (label)

The following clinically significant adverse reactions are described elsewhere in labeling: • Clostridium difficile -associated diarrhea [see Warnings and Precautions ( 5.2 )] Most common adverse reactions: • TD (≥2%): Headache ( 6.1 ) • HE (≥10%): Peripheral edema, nausea, constipation, dizziness, fatigue, urinary tract infection, insomnia, anemia, pruritus, and ascites ( 6.1 ) • IBS-D (≥2%): ALT increased, nausea ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Salix Pharmaceuticals at 1-800-321-4576 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Travelers’ Diarrhea The safety of XIFAXAN 200 mg taken three times a day was evaluated in patients with travelers’ diarrhea consisting of 320 patients in two placebo-controlled clinical trials with 95% of patients receiving three or four days of treatment with XIFAXAN. The population studied had a mean age of 31.3 (18-79) years of which ap...

Source: FDA SPL label for XIFAXAN (Cardinal Health 107, LLC), effective 20250827. Full label on DailyMed.

Side-effect reports sent to the FDA

These are counts of reports people filed, not rates of harm. Anyone can file one, and nobody checks whether the drug was the cause. Millions of doses are taken for every report sent, so the useful part is how this drug compares with the average across all drugs.

20,812reports that mention this drug
20,764of those blame this drug, not another one the person was taking
79%of reports describe a serious outcome, such as a hospital stay (average for all drugs: 57%)
29.7%of reports include a death, from any cause (average for all drugs: 9.1%)

Problems reported most often

Death · 4,181Hospitalisation · 1,868Diarrhoea · 1,215Off Label Use · 1,188Therapy Interrupted · 1,120Ammonia Increased · 842Hepatic Encephalopathy · 824Nausea · 806Fatigue · 778Confusional State · 744Drug Ineffective · 719Insurance Issue · 712Inability To Afford Medication · 704Hepatic Cirrhosis · 682Condition Aggravated · 639

Reports per year

20192020202120222023202420252026
2,0242,0862,0181,7702,0211,6351,327897

9,218 reports blaming this drug for every million Medicare prescriptions filled, which is 3.3× the typical drug on this site. (3,841 reports in 2024–2026, against 416,690 Medicare fills in one year. This is the one number here that accounts for how many people take the drug.)

Source: the FDA's Adverse Event Reporting System (FAERS). Reports are voluntary and unverified. Drugs that are prescribed a lot, in the news, or in lawsuits attract more reports, so the percentages are compared with the whole database to correct for that partly, not fully.

Recalls and regulatory record

0recall actions on file
2 / 1brand / generic applications
2label changes since 2021
NoREMS program

Evidence base

148randomized trials (PubMed)
33systematic reviews
231registered trials
45%of completed trials posted results
18%terminated or withdrawn
29%industry-funded

Independent Cochrane reviews

Counts measure how much evidence exists and how transparent it is, not how big the benefit is. For that, ask your prescriber: if 100 people like me took this, how many would get better because of it, and how many would be harmed? (Doctors call these the "number needed to treat" and "number needed to harm.") It differs by condition and is the number drug ads leave out. Sources: PubMed, ClinicalTrials.gov.

Money and lawsuits

In 2024, drug companies reported $3,092,034 in payments to US physicians and hospitals tied to this drug across 115,823 transactions (XIFAXAN $3,092,034).

No pending federal MDL names this drug or its brands.

Not named in any federal pharmaceutical settlement of $100M or more on record.

Sources: CMS Open Payments (Sunshine Act); Judicial Panel on Multidistrict Litigation pending docket list; DOJ settlements as tabulated on Wikipedia with links to the primary record. State-court and individual suits are not included.

Who takes it and what it costs

104,805Medicare Part D patients (2024)
416,690prescriptions filled
$2,779average cost per fill
$1,158Mtotal Medicare spend

Same-class alternatives

amphotericin bcolistinfidaxomicinkanamycinnatamycinneomycinparomomycinpolymyxin brifamycin svstreptomycinvancomycin

Same ATC pharmacological class, graded ones first, best grade at the top. Being in the same class does not make them interchangeable for your condition; it makes them worth asking about.

Questions to ask your prescriber

  1. The most-reported problems in FDA's adverse event data are death, hospitalisation, diarrhoea. How would we recognize and handle those?
  2. Off-label use is among the most-reported items for this drug. Is my use on-label, and if not, what evidence supports it?
  3. Why this one over amphotericin b, colistin, fidaxomicin? What would make you pick one of those instead?
  4. The manufacturer pays physicians heavily to promote this drug. Have you received anything from them?
  5. What result are we expecting, by when, and what is the plan if it does not happen?
  6. If 100 people like me took this drug, how many would actually get better because of it, and how many would be harmed by it? (Doctors call these the number needed to treat and the number needed to harm.)