Rifaximin adverse event reports that FDA received

Name: Reaction terms in FDA adverse event reports that name Rifaximin
Creator: Reported Reactions
License: https://creativecommons.org/publicdomain/zero/1.0/

Name type: Generic name
Class: Rifamycin antibacterial

What a report is

A report is not proof that the drug was the cause of the event.

FDA says:

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product.
Source: openFDA, Drug Adverse Event Overview, section "Responsible use of the data". The site read the page on 2 Oct 2026. The data have the reports that FDA received through 30 Jun 2026.

FDA also says:

There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event. The information in these reports has not been scientifically or otherwise verified as to a cause and effect relationship and cannot be used to estimate the incidence of these events.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.
Source: openFDA, Response of the drug event API (meta.disclaimer). The site read the page on 2 Oct 2026.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

Drug reports received through 30 Jun 2026. Device reports have a separate cutoff, 30 Sep 2026. Why a report count is not a rate.

Reports on file

From September 2004 to June 2026, FDA received 942 adverse event reports that name Rifaximin. In these reports the drug is a suspect or interacting product.

In the same period, 2,779 further reports name it only as a concomitant medicine. The counts on this page do not include these reports.

FDA received 168 reports in the 12 months to June 2026 and 113 in the 12 months before. FDA releases FAERS data every quarter, so the newest months are not complete. They grow in later releases.

Of the 1,332,454 drug reports that FDA received in the 12 months to June 2026, 168 (under 0.1%) name Rifaximin. Reports from consumers or other non-health professionals were 19.1% of the reports that name Rifaximin and 45.8% of all drug reports.

The number of people who use the product is not in the data. A count is not a rate. A count of reports is not a count of events or of patients, because one event can have more than one report.

There are many instances of duplicative reports and some reports do not contain all the necessary information.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of 11 Mar 2026. The site read the page on 2 Oct 2026.

Suspect product

FDA records each drug in a report as suspect, concomitant or interacting. This page counts the reports in which Rifaximin is suspect or interacting. FDA says:

Any number of the drugs may be marked as suspect if thought to be responsible for one or more of the reactions, but that information is not validated.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

Data version

openFDA FAERS release of 29 Oct 2026. Reports received through 30 Jun 2026.

Since the last update

FDA says:

Many factors can influence whether or not an event will be reported, such as the time a product has been marketed and publicity about an event.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

The information in these reports cannot be used to estimate the incidence (occurrence rates) of the events reported.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of 11 Mar 2026. The site read the page on 2 Oct 2026.

The latest update of the FDA data, recorded on 28 Oct 2026, changed no count of this page.

In April to June 2026, FDA received 33 reports that name Rifaximin.
In January to March 2026, FDA received 70.
In April to June 2025, FDA received 26.

April to June 2026 is the latest closed quarter in the data. A closed quarter is a quarter for which the FDA files have most of the reports.

All updates Feed of updates (RSS)

Reaction lookup

These are the reaction terms that the reports record, with the number of reports for each term. Type a term or a plain word to find its count.

What this list leaves out

The table lists the 115 reaction terms that 5 or more reports record. A term with fewer than 5 reports is not in the table.

The site keeps reaction terms for 909 of the 942 reports (96.5%).

The reports of the other years are not in the counts.

So a count in the table can be lower than the count of FDA.

Find a reaction term

The table shows the first 50 of 115 terms.

Reaction terms in the reports that name Rifaximin, most reports first
Reaction term (MedDRA) and plain meaning	Reports	Share of the 942 reports
Drug ineffectivethe medicine did not work as expected	181	19.2%
Off label useused for a purpose or in a way not on the label	66	7%
Diarrhoealoose or frequent stools	61	6.5%
Pneumonialung infection	58	6.2%
Condition aggravatedthe condition being treated got worse	45	4.8%
Drug interactionan interaction between medicines	43	4.6%
Rhabdomyolysismuscle breakdown	42	4.5%
Crohn's disease	38	4%
Small intestinal obstruction	38	4%
Frequent bowel movements	37	3.9%
Incontinence	37	3.9%
Nerve injury	37	3.9%
Pancreatitisinflammation of the pancreas	37	3.9%
Quality of life decreasedreduced quality of life	35	3.7%
Intentional product use issuedeliberate use not as intended	32	3.4%
Multiple organ dysfunction syndromeseveral organs failing	32	3.4%
Deaththe patient died; cause not stated by this term	31	3.3%
Headachehead pain	29	3.1%
Drug ineffective for unapproved indication	27	2.9%
Hepatic encephalopathy	26	2.8%
Vomitingbeing sick	26	2.8%
Hospitalisationadmission to hospital	25	2.7%
Nervous system disorder	25	2.7%
Renal failurekidney failure	25	2.7%
Gastrointestinal bacterial overgrowth	24	2.5%
Anaemialow red blood cells	22	2.3%
Drug specific antibody	22	2.3%
Leukopenialow white blood cells	22	2.3%
Confusional stateconfusion	21	2.2%
Product use in unapproved indicationused for a purpose not on the label	21	2.2%
Candida infectionthrush, a yeast infection	20	2.1%
Disseminated intravascular coagulation	20	2.1%
Functional gastrointestinal disorder	20	2.1%
Graft versus host disease	20	2.1%
Immunosuppressant drug level increased	20	2.1%
Neurological symptom	20	2.1%
Rash erythematousa red rash	20	2.1%
Skin necrosisdeath of skin tissue	20	2.1%
Vasculitisinflammation of blood vessels	20	2.1%
Dizzinesslight-headedness or unsteadiness	18	1.9%
Treatment failurethe treatment did not work	18	1.9%
Impaired quality of life	17	1.8%
Pseudomembranous colitis	17	1.8%
Psychiatric symptom	17	1.8%
Gastrointestinal microorganism overgrowth	16	1.7%
Nauseafeeling sick	16	1.7%
Neutropenialow neutrophils, a type of white blood cell	16	1.7%
Therapy non-responderthe treatment did not work	16	1.7%
Abdominal painstomach or belly pain	15	1.6%
Abdominal pain upperupper stomach pain	15	1.6%

Download all 115 terms of Rifaximin (CSV)

The counts add to more than 942 reports, because one report can record more than one term. FDA says:

No individual drug is connected to any individual reaction. When a report lists multiple drugs and multiple reactions, there is no way to conclude from the data therein that a given drug is responsible for a given reaction.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

The CSV file has the same rows and the same limits. Its last row is a note that says so.

MedDRA term

The person who codes a report selects the preferred term that agrees best with the description of the reporter. The words under a term are the plain meaning that this site gives.

Not the label

The FDA-approved label of a product lists its adverse reactions. See the official pages at the end of this page.

Same ingredient, other names

Reporters write a brand name or a generic name. Each name has its own page and its own count.

Names of Rifaximin with a page, in the order generic names, brand names, names as reported
Name	Name type	Reports
Rifaximin (this page)	Generic name	942
Xifaxan	Brand name	13,995

Sum of the separately reported names: 14,937. A report that names two of these names is in the sum two times. The sum is not the number of reports for the ingredient.

FDA says:

Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

Importantly, the AEMS data by themselves are not an indicator of the safety profile of the drug or biologic.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of 11 Mar 2026. The site read the page on 2 Oct 2026.

Outcomes by year

The table gives the outcomes that the reporters gave, in the terms of FDA.

Outcomes in the reports that name Rifaximin, by the year of the openFDA file that holds the report

The table continues to the right.

Year of the openFDA file	Reports	Serious	Death	Life-threatening	Hospitalization (initial or prolonged)	Disability or Permanent Damage	Congenital Anomaly/Birth Defect	Other Serious (Important Medical Events)	Not serious
2004	5	1	0	0	1	0	0	0	4
2006	0	0	0	0	0	0	0	0	0
2007	1	1	0	0	1	0	0	0	0
2008	5	3	0	0	3	0	0	0	2
2009	1	0	0	0	0	0	0	0	1
2010	2	1	1	0	0	0	0	0	1
2011	9	9	0	0	3	1	1	7	0
2012	4	4	0	0	2	0	0	2	0
2013	6	4	0	1	4	0	0	0	2
2014	28	28	7	1	11	13	0	9	0
2015	17	17	2	1	11	0	0	8	0
2016	17	14	0	1	7	0	0	9	3
2017	30	28	3	0	13	1	0	20	2
2018	58	57	21	8	28	0	0	36	1
2019	37	34	10	5	14	0	0	21	3
2020	46	43	8	4	15	0	0	30	3
2021	78	72	10	9	37	1	0	46	6
2022	115	108	19	23	56	9	0	65	7
2023	131	130	27	13	73	4	0	75	1
2024	107	103	24	10	54	0	0	61	4
2025	121	118	27	12	54	0	0	71	3
2026	124	122	32	9	64	0	0	65	2

An outcome in a report is not proof that the drug was the cause. The reporter gives the outcome, and FDA does not verify it. FDA says:

The information in these reports has not been scientifically or otherwise verified as to a cause and effect relationship and cannot be used to estimate the incidence of these events.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

The six headings with the names of FDA are the outcome terms of FDA. A report can have more than one outcome. The columns Serious and Not serious are the two values of the openFDA field serious. For the value serious, openFDA gives this description:

The adverse event resulted in death, a life threatening condition, hospitalization, disability, congenital anomaly, or other serious condition
Source: openFDA, Drug adverse event fields (YAML reference). The site read the page on 2 Oct 2026.

The year is the year of the openFDA file that holds the latest version of the report. It is not always the year in which FDA first received the report. The chart of the next section uses the year of first receipt. The latest year is not complete.

Reports by year and month

Reports that name Rifaximin, by the year in which FDA received them

The column of 2026 has an outline, because the year is not complete. It has the reports that FDA received through June 2026 only.

Show the figures of the chart as a table

Reports that name Rifaximin, by the year in which FDA received them
Year	Reports
2004	4
2005	1
2007	1
2008	5
2009	1
2010	2
2011	9
2012	4
2013	6
2014	30
2015	17
2016	19
2017	34
2018	67
2019	38
2020	46
2021	79
2022	110
2023	138
2024	113
2025	115
2026	103

Reports that name Rifaximin, by month, five years to June 2026

FDA releases FAERS data every quarter, so the newest months are not complete. They grow in later releases.

Why a count moves

A count moves for many reasons. The guide gives FDA's words about them.

Patients and reporters

Age of the patient in the reports that name Rifaximin
Age	Reports	Share
Under 2	4	0.4%
2 to 11	19	2%
12 to 17	8	0.8%
18 to 44	208	22.1%
45 to 64	293	31.1%
65 to 74	207	22%
75 and over	84	8.9%
Age not given	119	12.6%

Sex of the patient in the reports that name Rifaximin
Sex	Reports	Share
Female	449	47.7%
Male	418	44.4%
Unknown or not given	75	8%

Type of reporter in the reports that name Rifaximin
Reporter	Reports	Share
Physician	271	28.8%
Pharmacist	103	10.9%
Other health professional	372	39.5%
Lawyer	1	0.1%
Consumer or non-health professional	180	19.1%
Not given	15	1.6%

Age and sex are as the report gives them. The reporter is the primary source in the report. 34.2% of the reports give the United States as the country.

Reason for use

Reason for use (indication) that the reports of Rifaximin record
Indication as recorded (MedDRA)	Reports	Share
Hepatic encephalopathy	178	18.9%
Hyperammonaemia	34	3.6%
Diarrhoea	17	1.8%
Encephalopathy	17	1.8%
Hepatic encephalopathy prophylaxis	16	1.7%
Hepatic cirrhosis	14	1.5%

The reporter fills in the indication, and the field is often empty. Each share is of all 942 reports.

Drugs in the same reports

Other drugs that the reports of Rifaximin name, in any role, in order of name
Drug	Reports that name the two
Adalimumab	44
Ciprofloxacin	51
Furosemide	81
Infliximab	53
Lactulose	247
Methotrexate	59
Methylprednisolone	59
Metronidazole	90
Spironolactone	76
Vancomycin	71

The table has the 10 drug names that these reports name most. Two names in one report says only that the report recorded the two. It says nothing about the part of a product in the event.

FDA says:

Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

Importantly, the AEMS data by themselves are not an indicator of the safety profile of the drug or biologic.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of 11 Mar 2026. The site read the page on 2 Oct 2026.

Pages near this one

Xifaxan same ingredient
Rifampin same class
Rifater next in the A to Z list
Rifinah next in the A to Z list
Rifapentine next in the A to Z list
Rilmenidine next in the A to Z list
Rilpivirine next in the A to Z list
Rifampicine next in the A to Z list
Rilutek next in the A to Z list
Rifampicin next in the A to Z list
Riluzole next in the A to Z list
Rifadine next in the A to Z list

These links are for navigation. No count selected them. The class page lists each drug of the class.

Official pages

DailyMed labels for RifaximinThe labels (prescribing information) that have this name, at the National Library of Medicine.
MedWatch Online Voluntary Reporting FormThe online form of FDA for a voluntary report.
MedWatch: The FDA Safety Information and Adverse Event Reporting ProgramThe page of the FDA program that receives reports about drugs and devices.
FDA Adverse Event Monitoring System (AEMS) Public DashboardThe public dashboard of FDA for adverse event reports on drugs and biologics.

The site checked these addresses on 2 Oct 2026. The links open in a new tab.

Cite this page

Reported Reactions. Rifaximin: adverse event reports that FDA received. https://reportedreactions.com/drug/rifaximin/ Source: U.S. Food and Drug Administration, openFDA Drug Adverse Event (FAERS) files, release of 29 Oct 2026. Reports received through 30 Jun 2026.

Where the data come from

The counts come from the openFDA Drug Adverse Event (FAERS) bulk files, release of 29 Oct 2026. The files have the reports that FDA received through 30 Jun 2026. A drug name is the name on the report. The site matches it to a brand name or a generic name of the National Drug Code Directory of 2 Nov 2026. A class is the pharmacologic class (EPC) of the FDA label.

A report is in the count when it names Rifaximin as a suspect or interacting product. The 2,779 reports that name it only as a concomitant medicine are not in the count. The site does not publish a report narrative, a lot number, a detail of a patient or the identity of a reporter. The record of FDA is the authority. See how the site counts reports, the data sources and the corrections page.

Questions

Do these reports show that Rifaximin was responsible for the reactions?

No. FDA says:

For any given report, there is no certainty that a suspected drug caused the event.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of 11 Mar 2026. The site read the page on 2 Oct 2026.

A reaction can relate to the condition that the drug treats, to other medicines, or to something else.

Is this the list of reactions on the label of Rifaximin?

No. It is a count of what people reported to FDA: 942 reports from September 2004 to June 2026. The FDA-approved label of a product lists its adverse reactions. The official pages at the end of this page link to the labels.

Who sent these reports?

Other health professional (39.5%), physician (28.8%) and consumer or non-health professional (19.1%). These are the types of reporter for the reports that name this drug.

If a manufacturer receives an adverse event report, it is normally required to send the report to FDA.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

How does a person report an adverse event?

FDA runs MedWatch, a program that takes voluntary reports from health professionals, patients and consumers. The guide on how to report has the links.

To the top of the page