Rituxanrituximab
According to the FDA label: RITUXAN is a CD20-directed cytolytic antibody indicated for the treatment of: Adult patients with Non-Hodgkin's Lymphoma (NHL) ( 1.1 ). Relapsed or refractory, low grade or follicular, CD20-positive B-cell NHL as a single agent. Previously untreated follicular, CD20-positive, B-cell NHL in combination with first line chemotherapy and, in patients achieving a complete or partial response to a rituximab product in combination with chemotherapy, as single-agent maintenance therapy.
205,590 adverse event reports submitted to the FDA (1999–2026)
Top Reported Adverse Events
The most frequently reported events in association with Rituxan in the FAERS database. These are events reported by patients taking this medication, not necessarily caused by it. A single report may include multiple events.
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Off Label Use 39,617 reports
Using a medication for a condition or in a way that the FDA has not officially approved. This is common and often legal, and a report of it does not mean something went wrong. Doctors sometimes prescribe drugs off label based on their judgment.
Full definition in the glossary →Drug Ineffective 33,592 reports
A report that the medication did not work as expected for the person taking it. This is a reporting category, not a sign the drug is defective. It simply means someone felt it was not helping their condition.
Full definition in the glossary →Rheumatoid Arthritis 19,804 reports
An autoimmune condition where the immune system attacks the joints, causing pain and swelling. It often appears in reports because it is a condition being treated, not always a reaction.
Full definition in the glossary →Pain 17,435 reports
A general report of physical discomfort, used when no more specific location is given.
Full definition in the glossary →Fatigue 16,912 reports
Extreme tiredness or lack of energy that does not improve with rest.
Full definition in the glossary → See all drugs reporting this event →Rash 13,187 reports
An area of irritated, red, or bumpy skin.
Full definition in the glossary → See all drugs reporting this event →Arthralgia 13,074 reports
Pneumonia 12,491 reports
An infection that inflames the air sacs in the lungs, which can cause cough, fever, and difficulty breathing.
Full definition in the glossary →Infusion Related Reaction 12,419 reports
A reaction that happens during or shortly after a medication is given through an IV infusion.
Full definition in the glossary →Drug Intolerance 12,256 reports
A report that the person could not tolerate a medication, often due to uncomfortable effects.
Full definition in the glossary →Joint Swelling 11,662 reports
Swelling in or around a joint.
Full definition in the glossary →Pyrexia 11,464 reports
The medical term for fever, meaning a raised body temperature.
Full definition in the glossary → See all drugs reporting this event →Nausea 11,384 reports
The feeling of sickness in your stomach that often comes before vomiting.
Full definition in the glossary → See all drugs reporting this event →Infection 10,817 reports
A general report of an infection, used when no more specific type is given.
Full definition in the glossary →Alopecia 10,666 reports
Ranked by frequency of reports, not severity. The most-reported event is not necessarily the most dangerous or the most common in patients taking this drug.
Who Is Reporting
Demographics of patients in FAERS reports that included this information. Not all reports include patient demographics.
By Sex
View reporter sex data as a table
| Sex | Reports |
|---|---|
| Female | 94,464 |
| Male | 66,767 |
| Unknown | 1,768 |
By Age Group
View age group data as a table
| Age group | Reports |
|---|---|
| 0-17 | 7,523 |
| 18-34 | 9,788 |
| 35-49 | 23,431 |
| 50-64 | 37,915 |
| 65-74 | 29,445 |
| 75+ | 16,875 |
This shows who filed reports, reflecting who takes this drug and who tends to report, not who is at greatest risk.
Reported Outcomes
Outcomes recorded in FAERS reports that included Rituxan. A single report may involve multiple reactions, each with a different outcome. These categories are defined by FDA reporting guidelines, not by PillSignal.
View outcome data as a table
| Outcome | Reports |
|---|---|
| Other Serious | 131,383 |
| Hospitalization | 66,066 |
| Death | 36,037 |
| Non-Serious | 22,022 |
| Life-Threatening | 16,708 |
| Disability | 11,020 |
Serious outcomes are far more likely to be reported than mild ones, so this overstates how often outcomes are serious. A recorded death does not mean the drug caused it.
Report Volume Over Time
Number of FAERS reports received per quarter for Rituxan. Changes in volume may reflect shifts in prescribing rates, media attention, or reporting behavior, not changes in the medication's safety profile.
View report trend as a table
| Year | Reports |
|---|---|
| 1999 | 1 |
| 2004 | 509 |
| 2005 | 739 |
| 2006 | 723 |
| 2007 | 1,255 |
| 2008 | 1,417 |
| 2009 | 2,038 |
| 2010 | 2,486 |
| 2011 | 3,185 |
| 2012 | 4,697 |
| 2013 | 4,806 |
| 2014 | 5,019 |
| 2015 | 5,951 |
| 2016 | 6,767 |
| 2017 | 11,205 |
| 2018 | 12,324 |
| 2019 | 14,968 |
| 2020 | 20,531 |
| 2021 | 18,588 |
| 2022 | 21,330 |
| 2023 | 20,222 |
| 2024 | 24,162 |
| 2025 | 18,853 |
| 2026 (partial) | 3,814 |
The steep increase around 2004 reflects the FDA's move to electronic submission, not a change in this drug's safety. Trends track reporting volume, not risk.
Medications commonly reported with Rituxan
In FDA adverse event reports that mention Rituxan, these medications appeared most often in the same report.
- Prednisone (66,554 reports)
- Methotrexate (51,945 reports)
- Cyclophosphamide (51,230 reports)
- Cyclophosphamide For (51,230 reports)
- Doxorubicin (33,559 reports)
This reflects co-occurrence in submitted reports, not evidence of drug interaction or combined risk. People often report several medications taken for the same condition or for unrelated reasons. Talk to a doctor or pharmacist about your specific medications.
Related Drugs
Other medications with similar adverse event profiles in FDA FAERS reports.
Data Source
This data is sourced from the FDA's Adverse Event Monitoring System (AEMS), formerly FAERS, via the OpenFDA API. PillSignal is not affiliated with the FDA.
View this data on the FDA website →Data last updated: June 2026