Prescription medication · Non-Systemic Antibiotic (IBS-D)
rifaximin
Also sold as Xifaxan. Xifaxan can treat traveler's diarrhea caused by certain germs in adults and kids 12 and older.
Data updated 2026-05-15
- 19,891
- FDA reportsModerately reported
- 2
- InteractionsFew interactions
- $52.22
- Brand price (NADAC)
What the data shows
rifaximin (Xifaxan) is a prescription Non-Systemic Antibiotic (IBS-D), reported at a middle-of-the-pack volume (19,891 FDA reports), with 2 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
rifaximin (Xifaxan) is a prescription Non-Systemic Antibiotic (IBS-D). Xifaxan can treat traveler's diarrhea caused by certain germs in adults and kids 12 and older.
Xifaxan is an antibiotic medicine. It helps treat traveler's diarrhea and irritable bowel syndrome with diarrhea (IBS-D). It also lowers the risk of hepatic encephalopathy (HE) coming back.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Brand Price
$52.22/unit
Generic Available
No
SALIX PHARMS
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Xifaxan can treat traveler's diarrhea caused by certain germs in adults and kids 12 and older.
Common side effects
Headache, Swelling in your legs or ankles, Nausea
Key warnings
Xifaxan may not work if you have a fever or blood in your stool.
The sections below are summarized in plain English from rifaximin's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Xifaxan is an antibiotic that works in your gut. It stops the growth of certain bacteria that can cause diarrhea or other problems. It also reduces the amount of ammonia in your body, which can help with HE.
Side Effects (from patient reports)
Based on 19,891 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for rifaximin, by number of reports
- Death
Death
3,982 reports
- Hospitalisation
Hospitalisation
1,704 reports
- Diarrhoea 1,193
Diarrhoea
1,193 reports
- Therapy Interrupted 989
Therapy Interrupted
989 reports
- Ammonia Increased 831
Ammonia Increased
831 reports
- Nausea 802
Nausea
802 reports
- Fatigue 779
Fatigue
779 reports
- Hepatic Encephalopathy 762
Hepatic Encephalopathy
762 reports
- Confusional State 711
Confusional State
711 reports
- Inability To Afford Medication 679
Inability To Afford Medication
679 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for rifaximin each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where rifaximin sits
rifaximin has more FDA adverse-event reports than 55% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is rifaximin; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 19,891 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
19,891
Reports Mentioning Death
5,855
29.4% of reports — not proof of cause
Hospitalization Reports
7,784
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | DEATH | 3,982 |
| 2 | HOSPITALISATION | 1,704 |
| 3 | DIARRHOEA | 1,193 |
| 5 | THERAPY INTERRUPTED | 989 |
| 6 | AMMONIA INCREASED | 831 |
| 7 | NAUSEA | 802 |
| 8 | FATIGUE | 779 |
| 9 | HEPATIC ENCEPHALOPATHY | 762 |
| 11 | CONFUSIONAL STATE | 711 |
| 12 | INABILITY TO AFFORD MEDICATION | 679 |
| 13 | HEPATIC CIRRHOSIS | 657 |
| 14 | INSURANCE ISSUE | 623 |
| 15 | FALL | 607 |
| 16 | CONDITION AGGRAVATED | 603 |
| 17 | DIZZINESS | 517 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Xifaxan may not work if you have a fever or blood in your stool. It may also not work for diarrhea caused by germs other than E. coli. If your diarrhea gets worse or lasts more than 1-2 days, stop taking Xifaxan and talk to your doctor. Diarrhea caused by C. difficile can happen with almost all antibiotics, including Xifaxan. Use Xifaxan with caution if you have severe liver problems.
Known Drug Interactions
( 7.2 ) 7.1 P-glycoprotein Inhibitors Concomitant administration of cyclosporine, an inhibitor of P-gp and OATPs significantly increased the systemic exposure of rifaximin. Caution should be exercised when concomitant use of XIFAXAN and a P-gp inhibitor such as cyclosporine is needed [see Warnings and Precautions ( 5.5 ), Clinical Pharmacology ( 12.3 )].
Mechanism: Cyclosporine stops certain proteins from removing rifaximin from the body, which causes rifaximin levels to rise.
7 DRUG INTERACTIONS Warfarin: Monitor INR and prothrombin time; dose adjustment of warfarin may be needed to maintain target INR range. 7.2 Warfarin Changes in INR have been reported postmarketing in patients receiving rifaximin and warfarin concomitantly. Dose adjustment of warfarin may be needed to maintain target INR range.
Mechanism: Rifaximin can affect how your body processes blood thinners, which may change your risk of bleeding or how quickly your blood clots.
This is a plain-language summary of FDA-label interaction records and does not provide individual medication-combination directions.
Common Questions
Can I take Xifaxan if I'm allergic to rifampin?
What should I tell my doctor before taking Xifaxan?
Can Xifaxan cause other problems?
How long should I take Xifaxan?
Can I drink alcohol while taking Xifaxan?
What if my IBS-D symptoms come back after treatment?
Does Xifaxan interact with other medications?
Can children take Xifaxan?
What are the symptoms of hepatic encephalopathy?
What if I accidentally take too much Xifaxan?
What are the common side effects of rifaximin?
Does rifaximin interact with other medications?
What drug class is rifaximin?
What pregnancy or breastfeeding source fields are listed for rifaximin?
Related Medications in Non-Systemic Antibiotic (IBS-D)
Other drugs grouped near rifaximin - same-class peers and common alternatives.
alosetron
Lotronex
Alosetron (Lotronex) is a medicine for women with severe diarrhea-predominant irritable bowel syndrome (IBS).
Compare with rifaximin →
aprepitant
Emend
Aprepitant (Emend) is a medicine that helps prevent nausea and vomiting.
Compare with rifaximin →
bisacodyl
Dulcolax
Bisacodyl is a medicine that helps you have a bowel movement.
Compare with rifaximin →
bismuth subsalicylate
Pepto-Bismol
Bismuth subsalicylate (Pepto-Bismol) is a medicine that can treat diarrhea and upset stomach.
Compare with rifaximin →
cimetidine
Tagamet
Cimetidine (Tagamet) reduces stomach acid.
Compare with rifaximin →
Compare beyond drug class
Nationwide peers by FAERS volume & death-report share
Two PlainMeds-derived comparison paths for rifaximin: nearest FDA FAERS report volume and nearest death-report share among drugs with at least 1,000 logged reports, excluding same-class neighbors listed above. Counts reflect reporting volume, not proven individual harm.
Similar FAERS report volume
Nearest drugs by total FAERS reports. This record: 19,891.
Similar death-report share
Nearest drugs by FAERS death-report share. This record: 29.44%.
- voriconazole Δ 0.08 pts · 29,380 reports · Azole Antifungal 29.52%death share
- aflibercept Δ 0.17 pts · 29,874 reports · Anti-VEGF (Ophthalmic Injection) 29.61%death share
- meropenem Δ 0.53 pts · 30,400 reports · Carbapenem Antibiotic 29.97%death share
- buprenorphine Δ 0.77 pts · 90,121 reports · Partial Opioid Agonist 28.67%death share
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Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for rifaximin
The FDA label for rifaximin (sold under brand names such as Xifaxan) classifies it as a prescription-only medication in the Non-Systemic Antibiotic (IBS-D) class. Xifaxan can treat traveler's diarrhea caused by certain germs in adults and kids 12 and older. Official labeling lists 12 commonly reported side effects, including Headache, Swelling in your legs or ankles, Nausea.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 19,891 voluntary reports. The database also lists 2 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. This registry does not provide medication decisions.
Last updated: August 27, 2025
PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages