Drug · FAERS side-effect profile with label screen
Rifaximin side effects: what 20,825 FDA adverse event reports show
Drug class
Rifamycin Antibacterial
FDA label (Established Pharmacologic Class)
Brand names
Xifaxan
openFDA label
Who reports
20,825 reports · 78% serious · 6,105 with death outcome · 52% female
openFDA FAERS counts, all years, deduplication not applied
Used for
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.
FDA label, Indications and Usage
What it is
XIFAXAN tablets contain rifaximin, a non-aminoglycoside semi-synthetic, nonsystemic antibiotic derived from rifamycin SV. Rifaximin is a structural analog of rifampin.
FDA label, Description section
Boxed warning
None in the current label
How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation.
Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)?
That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.
Causality screen of the 40 strongest signals
Labeled (related wording) 6Likely indication confounding 2Reporting / coding artifact 3Lab value / disease marker 4Not in label — unassessed 25
What the badges mean
- Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
- Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
- Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
- Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
- Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.
Strongest disproportionality signals
Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 1,053 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
Show:
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Portal shunt procedure | 24 | 541.4 329.3–890.1ROR 542.0 · χ² 8,031 / p <1e-300 | 274.1 EB05 193.9 · IC025 +4.7 3/3 methods agree | Reporting / coding artifact | serious n=24 · ♀ 25% (drug 52%) · 79% consumer | not reported in cached trials |
| Gastrointestinal bacterial overgrowth | 114 | 232.4 189.6–284.8ROR 233.6 · χ² 21,093 / p <1e-300 | 182.7 EB05 156.3 · IC025 +6.4 3/3 methods agree | Labeled (related wording) related wording | serious n=53 · ♀ 84% (drug 52%) · 70% consumer | not reported in cached trials |
| Ammonia increased | 852 | 202.2 188.1–217.4ROR 210.8 · χ² 141,560 / p <1e-300 | 167.5 EB05 158.3 · IC025 +7.1 3/3 methods agree | Lab value / disease marker | serious n=797 · 82% consumer | not reported in cached trials |
| Gastrointestinal microorganism overgrowth | 48 | 184.7 135.7–251.2ROR 185.1 · χ² 7,239 / p <1e-300 | 146.9 EB05 115.2 · IC025 +5.4 3/3 methods agree | Not in label — unassessed | serious n=31 · ♀ 89% (drug 52%) | not reported in cached trials |
| Ammonia abnormal | 59 | 172.2 130.7–227.0ROR 172.7 · χ² 8,414 / p <1e-300 | 140.3 EB05 112.8 · IC025 +5.6 3/3 methods agree | Lab value / disease marker | serious n=52 · 80% consumer | not reported in cached trials |
| Chronic hepatic failure | 92 | 165.4 132.7–206.2ROR 166.2 · χ² 12,748 / p <1e-300 | 137.9 EB05 115.9 · IC025 +6.0 3/3 methods agree | Labeled (related wording) related wording | serious n=92 | not reported in cached trials |
| Paracentesis | 57 | 102.3 77.9–134.3ROR 102.6 · χ² 5,093 / p <1e-300 | 90.1 EB05 72.1 · IC025 +5.3 3/3 methods agree | Not in label — unassessed | serious n=55 · 70% consumer | not reported in cached trials |
| Cirrhosis alcoholic | 40 | 96.1 69.5–133.0ROR 96.3 · χ² 3,347 / p <1e-300 | 84.3 EB05 64.6 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious n=40 | not reported in cached trials |
| Hepatic encephalopathy | 809 | 95.5 89.0–102.5ROR 99.3 · χ² 68,951 / p <1e-300 | 87.0 EB05 82.1 · IC025 +6.3 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 64.5 | not reported in cached trials |
| Overgrowth bacterial | 20 | 79.7 50.6–125.7ROR 79.8 · χ² 1,367 / p 1e-299 | 69.2 EB05 47.3 · IC025 +4.0 3/3 methods agree | Labeled (related wording) related wording | serious n=14 | not reported in cached trials |
| Inability to afford medication | 701 | 77.3 71.7–83.4ROR 79.9 · χ² 48,924 / p <1e-300 | 71.6 EB05 67.3 · IC025 +6.0 3/3 methods agree | Not in label — unassessed | serious n=580 | not reported in cached trials |
| Portal hypertensive gastropathy | 35 | 67.6 48.0–95.2ROR 67.7 · χ² 2,088 / p <1e-300 | 61.3 EB05 46.1 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious n=34 | not reported in cached trials |
| Spider naevus | 10 | 56.7 30.0–107.3ROR 56.7 · χ² 466 / p 1e-103 | 49.0 EB05 28.4 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=9 | not reported in cached trials |
| Insurance issue | 710 | 50.5 46.9–54.4ROR 52.3 · χ² 32,767 / p <1e-300 | 48.1 EB05 45.2 · IC025 +5.4 3/3 methods agree | Not in label — unassessed | serious PRR 62.8 · 77% consumer | not reported in cached trials |
| Liver transplant | 164 | 47.7 40.8–55.8ROR 48.1 · χ² 7,115 / p <1e-300 | 45.4 EB05 39.8 · IC025 +5.1 3/3 methods agree | Not in label — unassessed | serious n=162 · ♀ 31% (drug 52%) · 74% consumer | not reported in cached trials |
| Abdominal cavity drainage | 18 | 44.7 27.9–71.6ROR 44.7 · χ² 694 / p 3e-153 | 41.1 EB05 27.5 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious n=18 | not reported in cached trials |
| Hepatic cirrhosis | 692 | 38.7 35.9–41.7ROR 40.0 · χ² 24,440 / p <1e-300 | 37.2 EB05 35.0 · IC025 +5.1 3/3 methods agree | Labeled (related wording) related wording | serious PRR 27.7 | not reported in cached trials |
| Varices oesophageal | 105 | 36.3 29.9–44.0ROR 36.4 · χ² 3,440 / p <1e-300 | 34.8 EB05 29.6 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious n=100 | not reported in cached trials |
| Non-alcoholic steatohepatitis | 36 | 35.7 25.6–49.8ROR 35.8 · χ² 1,140 / p 3e-250 | 34.0 EB05 25.6 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=36 · 71% consumer | not reported in cached trials |
| Complications of transplanted liver | 12 | 34.2 19.3–60.8ROR 34.2 · χ² 343 / p 8e-77 | 31.6 EB05 19.2 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious n=12 | not reported in cached trials |
| Liver operation | 10 | 34.2 18.2–64.3ROR 34.2 · χ² 280 / p 3e-63 | 31.3 EB05 18.1 · IC025 +2.6 3/3 methods agree | Reporting / coding artifact | serious n=10 | not reported in cached trials |
| Gastric varices | 15 | 33.6 20.1–56.2ROR 33.6 · χ² 428 / p 2e-95 | 31.4 EB05 20.2 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious n=14 | not reported in cached trials |
| Ureaplasma infection | 12 | 30.8 17.3–54.7ROR 30.8 · χ² 307 / p 5e-69 | 28.6 EB05 17.4 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious n=12 | not reported in cached trials |
| Hepatorenal syndrome | 50 | 30.6 23.1–40.5ROR 30.6 · χ² 1,359 / p 1e-297 | 29.4 EB05 23.2 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=50 · ♀ 32% (drug 52%) | not reported in cached trials |
| Gastric antral vascular ectasia | 15 | 29.9 17.9–50.0ROR 29.9 · χ² 379 / p 1e-84 | 28.1 EB05 18.0 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious n=15 | not reported in cached trials |
| Hepatic infarction | 10 | 27.3 14.6–51.2ROR 27.4 · χ² 222 / p 2e-50 | 25.3 EB05 14.4 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious n=10 | not reported in cached trials |
| Hospice care | 235 | 24.6 21.6–28.0ROR 24.9 · χ² 5,169 / p <1e-300 | 24.0 EB05 21.5 · IC025 +4.3 3/3 methods agree | Not in label — unassessed | serious PRR 24.0 · 77% consumer | not reported in cached trials |
| Intra-abdominal fluid collection | 41 | 23.8 17.5–32.5ROR 23.9 · χ² 854 / p 5e-188 | 23.1 EB05 17.7 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious n=40 · 88% consumer | not reported in cached trials |
| Asterixis | 23 | 22.3 14.8–33.7ROR 22.3 · χ² 437 / p 2e-97 | 21.5 EB05 15.0 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious n=23 · ♀ 32% (drug 52%) | not reported in cached trials |
| Oesophageal varices haemorrhage | 46 | 21.7 16.2–29.1ROR 21.8 · χ² 870 / p 1e-191 | 21.1 EB05 16.5 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious n=45 | not reported in cached trials |
| Portal hypertension | 62 | 20.6 16.0–26.5ROR 20.7 · χ² 1,115 / p 1e-244 | 20.1 EB05 16.2 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious n=61 | not reported in cached trials |
| Hyperammonaemic encephalopathy | 33 | 19.8 14.0–27.9ROR 19.8 · χ² 558 / p 1e-123 | 19.2 EB05 14.2 · IC025 +3.3 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=33 · ♀ 21% (drug 52%) · 100% clinician | not reported in cached trials |
| Symptom recurrence | 108 | 18.9 15.6–22.8ROR 19.0 · χ² 1,776 / p <1e-300 | 18.5 EB05 15.7 · IC025 +3.8 3/3 methods agree | Labeled (related wording) related wording | serious n=36 · 86% consumer | not reported in cached trials |
| Megacolon | 27 | 17.7 12.1–25.8ROR 17.7 · χ² 401 / p 2e-89 | 17.1 EB05 12.2 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious n=27 · ♀ 23% (drug 52%) | not reported in cached trials |
| Enterococcus test positive | 11 | 17.2 9.5–31.3ROR 17.3 · χ² 150 / p 9e-35 | 15.8 EB05 8.4 · IC025 +2.3 3/3 methods agree | Lab value / disease marker | serious n=11 | not reported in cached trials |
| Hepatic failure | 496 | 16.8 15.4–18.3ROR 17.2 · χ² 7,236 / p <1e-300 | 16.5 EB05 15.3 · IC025 +3.9 3/3 methods agree | Labeled (related wording) related wording | serious PRR 12.2 | not reported in cached trials |
| Therapy interrupted | 1,119 | 16.6 15.7–17.6ROR 17.5 · χ² 16,159 / p <1e-300 | 16.3 EB05 15.5 · IC025 +3.9 3/3 methods agree | Reporting / coding artifact | serious PRR 24.6 · 81% consumer | not reported in cached trials |
| Drug specific antibody | 22 | 16.5 10.8–25.1ROR 16.5 · χ² 300 / p 2e-67 | 15.8 EB05 10.7 · IC025 +2.9 3/3 methods agree | Lab value / disease marker | serious n=22 · 100% clinician | not reported in cached trials |
| Short-bowel syndrome | 10 | 15.7 8.4–29.3ROR 15.7 · χ² 121 / p 2e-28 | 13.8 EB05 6.9 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious n=9 | not reported in cached trials |
| Pouchitis | 13 | 15.4 8.9–26.6ROR 15.4 · χ² 158 / p 1e-36 | 14.1 EB05 7.9 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious n=12 | not reported in cached trials |
Trial evidence (ClinicalTrials.gov)
✓ Trial adverse-event data found on ClinicalTrials.gov
Largest completed trials with posted results that list Rifaximin as a study intervention. The right-hand column of the signal table shows whether each FAERS term was also recorded in these trials, with a real denominator (0 of 40 signal terms matched).
- NCT01543178 — Irritable Bowel Syndrome With Diarrhea (IBS-D) Rifaximin Re-Treatment Study (N=2583, PHASE3; 48 AE terms posted; arms: Total Open-label Experience; Double-blind Retreatment Experience - Ri; Double-blind Retreatment Experience - Pl)
- NCT02498418 — Study Comparing Rifaximin With Xifaxan 200 mg in Traveler's Diarrhea (N=739, PHASE3; 22 AE terms posted; arms: Generic Rifaximin 200 mg Tablets; Xifaxan 200 mg Tablets; Rifaximin Placebo Tablets)
Caveats: trial populations, doses and follow-up differ from the reporting population; AE terms are sponsor-coded and matched here by wording; absence from a trial list means the term was not reported above the sponsor's frequency threshold, not that it cannot occur.
Most frequently reported reactions
By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Death | 4,162 | 4.9 4.8–5.0ROR 5.9 · χ² 13,340 / p <1e-300 | 4.9 EB05 4.7 · IC025 +2.2 3/3 methods agree | Outcome field, not a reaction | serious PRR 3.6 · 71% consumer | not reported in cached trials |
| Hospitalisation | 1,866 | 12.5 11.9–13.0ROR 13.6 · χ² 19,578 / p <1e-300 | 12.3 EB05 11.9 · IC025 +3.5 3/3 methods agree | Reporting / coding artifact | serious PRR 9.3 · 76% consumer | not reported in cached trials |
| Diarrhoea (diarrhea) | 1,243 | 1.9 1.8–2.1ROR 2.0 · χ² 589 / p 2e-130 | 1.9 EB05 1.9 · IC025 +0.9 | Likely indication confounding term in indications; also in warnings | serious PRR 1.4 | NCT01543178: 7/328 (2.1%) on Rifaximin; 3/308 (1.0%) control |
| Off label use (used outside approved label) | 1,168 | 1.4 1.3–1.4ROR 1.4 · χ² 113 / p 1e-26 | 1.4 EB05 1.3 · IC025 +0.3 | Reporting / coding artifact | serious PRR 0.8 | not reported in cached trials |
| Therapy interrupted | 1,119 | 16.6 15.7–17.6ROR 17.5 · χ² 16,159 / p <1e-300 | 16.3 EB05 15.5 · IC025 +3.9 3/3 methods agree | Reporting / coding artifact | serious PRR 24.6 · 81% consumer | not reported in cached trials |
| Ammonia increased | 852 | 202.2 188.1–217.4ROR 210.8 · χ² 141,560 / p <1e-300 | 167.5 EB05 158.3 · IC025 +7.1 3/3 methods agree | Lab value / disease marker | serious n=797 · 82% consumer | not reported in cached trials |
| Nausea | 837 | 1.1 1.0–1.1ROR 1.1 · χ² 4 / p 0.027 | 1.1 EB05 1.0 · IC025 -0.0 PRR-only: not supported by EBGM or IC | Labeled adverse reaction exact term | serious PRR 0.9 | NCT01543178: 12/328 (3.7%) on Rifaximin; 7/308 (2.3%) control |
| Hepatic encephalopathy | 809 | 95.5 89.0–102.5ROR 99.3 · χ² 68,951 / p <1e-300 | 87.0 EB05 82.1 · IC025 +6.3 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 64.5 | not reported in cached trials |
| Fatigue (tiredness) | 805 | 1.0 1.0–1.1ROR 1.0 · χ² 1 / p 0.113 | 1.0 EB05 1.0 · IC025 -0.1 PRR-only: not supported by EBGM or IC | Labeled adverse reaction exact term | serious PRR 0.9 | not reported in cached trials |
| Drug ineffective (drug did not work) | 740 | 0.6 0.5–0.6ROR 0.5 · χ² 263 / p 2e-59 | 0.6 EB05 0.5 · IC025 -0.9 PRR-only: not supported by EBGM or IC | Reporting / coding artifact | serious PRR 0.7 | not reported in cached trials |
| Confusional state (confusion) | 731 | 4.6 4.2–4.9ROR 4.7 · χ² 2,036 / p <1e-300 | 4.5 EB05 4.3 · IC025 +2.1 3/3 methods agree | Not in label — unassessed | serious PRR 3.7 | not reported in cached trials |
| Insurance issue | 710 | 50.5 46.9–54.4ROR 52.3 · χ² 32,767 / p <1e-300 | 48.1 EB05 45.2 · IC025 +5.4 3/3 methods agree | Not in label — unassessed | serious PRR 62.8 · 77% consumer | not reported in cached trials |
| Inability to afford medication | 701 | 77.3 71.7–83.4ROR 79.9 · χ² 48,924 / p <1e-300 | 71.6 EB05 67.3 · IC025 +6.0 3/3 methods agree | Not in label — unassessed | serious n=580 | not reported in cached trials |
| Hepatic cirrhosis | 692 | 38.7 35.9–41.7ROR 40.0 · χ² 24,440 / p <1e-300 | 37.2 EB05 35.0 · IC025 +5.1 3/3 methods agree | Labeled (related wording) related wording | serious PRR 27.7 | not reported in cached trials |
| Condition aggravated | 650 | 2.2 2.0–2.3ROR 2.2 · χ² 414 / p 3e-92 | 2.2 EB05 2.0 · IC025 +1.0 3/3 methods agree | Reporting / coding artifact | serious PRR 1.9 | not reported in cached trials |
Unlabeled candidate signals
These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.
- Gastrointestinal microorganism overgrowth — n=48, PRR 184.7
- Paracentesis — n=57, PRR 102.3
- Cirrhosis alcoholic — n=40, PRR 96.1
- Inability to afford medication — n=701, PRR 77.3
- Portal hypertensive gastropathy — n=35, PRR 67.6
- Insurance issue — n=710, PRR 50.5
- Liver transplant — n=164, PRR 47.7
- Varices oesophageal — n=105, PRR 36.3
- Non-alcoholic steatohepatitis — n=36, PRR 35.7
- Hepatorenal syndrome — n=50, PRR 30.6
Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.
Common questions
What are the most reported side effects of Rifaximin?
In FDA FAERS, the most frequently co-reported reaction terms for Rifaximin are diarrhoea, ammonia increased, nausea, hepatic encephalopathy, fatigue, confusional state. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.
Does Rifaximin have an FDA boxed warning?
No. The FDA label retrieved for Rifaximin has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Rifaximin causes these side effects?
No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.
Sources & methods
- FDA label via openFDA (set ID 7afafa63-3236-4212-9589-045db6b01c0b, effective 20250827; matched on
openfda.generic_name.exact:"RIFAXIMIN") - Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
- FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA
count=aggregation, fieldpatient.drug.openfda.generic_name.exact, 1,093 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction - Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
- Seriousness and sex counts from openFDA
count=serious,patient.patientsex,seriousnessdeath - ClinicalTrials.gov API v2 (query
RIFAXIMIN, results-bearing studies sorted by enrollment)
Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.