85/100 · Critical
Manufactured by Genentech, Inc.
Rituximab Adverse Events: High Seriousness and Diverse Reactions
743,156 FDA adverse event reports analyzed
Last updated: 2026-05-12
RITUXIMAB is a medication tracked in the FDA Adverse Event Reporting System (FAERS), manufactured by Genentech, Inc.. Based on analysis of 743,156 FDA adverse event reports, RITUXIMAB has a safety score of 85 out of 100. This score indicates a relatively favorable safety profile, with fewer or less severe adverse events compared to many other tracked medications. The most commonly reported adverse reactions for RITUXIMAB include OFF LABEL USE, DRUG INEFFECTIVE, RHEUMATOID ARTHRITIS, PAIN, FATIGUE. This page provides a comprehensive breakdown of reported side effects, safety signals, patient demographics, and AI-powered safety analysis for RITUXIMAB.
Rituximab has a safety concern score of 85 out of 100, placing it in the high concern category based on analysis of FDA adverse event data. The FDA has received approximately 743,156 adverse event reports for this medication, which is primarily manufactured by Genentech, Inc..
The most commonly reported adverse events include Off Label Use, Drug Ineffective, Rheumatoid Arthritis. Of classified reports, 89.2% were designated as serious by the FDA, meaning they involved hospitalization, disability, or other significant medical outcomes. High percentage of serious adverse events (89.2%) indicates significant safety concerns.
A wide range of reactions reported, including infections, infusion-related reactions, and autoimmune disorders. Fatigue, rash, and infusion-related reactions are among the most frequently reported issues.
Patients taking Rituximab should monitor for the commonly reported side effects and contact their healthcare provider if they experience any unusual symptoms. Rituximab can cause severe allergic reactions and infusion-related reactions. Patients should be monitored closely during and after administration. This analysis is based on voluntary FDA adverse event reports and should not replace professional medical advice.
Rituximab received a safety concern score of 85/100 (high concern). This is based on a 89.2% serious event ratio across 201,540 classified reports. The score accounts for 743,156 total adverse event reports and 100 distinct reaction types. This high score reflects a significant proportion of serious adverse events in the reporting data.
Adverse event reports by sex: Female: 92,649, Male: 65,505, Unknown: 1,768. The most frequently reported age groups are age 65 (3,905 reports), age 43 (3,624 reports), age 60 (3,395 reports). These demographics reflect reporting patterns and may not represent the full patient population.
Out of 201,540 classified reports for RITUXIMAB:
The FDA classifies an adverse event as “serious” if it results in death, hospitalization, disability, congenital anomaly, or requires intervention to prevent permanent damage.
Demographics reflect voluntary FDA adverse event reporting patterns and may not represent the full patient population.
Rituximab can cause severe allergic reactions and infusion-related reactions. Patients should be monitored closely during and after administration.
If you are taking Rituximab, here are important things to know. The most commonly reported side effects include off label use, drug ineffective, rheumatoid arthritis, pain, fatigue. While many of these may be mild and temporary, you should contact your healthcare provider if any symptoms are severe or persistent. Patients should report any adverse reactions immediately to their healthcare provider. Follow all prescribed dosing and administration guidelines to minimize the risk of adverse events. If you experience a serious adverse reaction, seek emergency medical attention immediately or call 911. You can report side effects to the FDA's MedWatch program at 1-800-FDA-1088.
The FDA continues to monitor Rituximab for safety, and updates are regularly issued based on new data.
The FDA has received approximately 743,156 adverse event reports associated with Rituximab. These reports come from healthcare professionals, consumers, and manufacturers through the FDA Adverse Event Reporting System (FAERS). Note that the number of reports does not directly indicate the frequency of side effects, as adverse events are voluntarily reported and may be underrepresented.
The most frequently reported adverse events for Rituximab include Off Label Use, Drug Ineffective, Rheumatoid Arthritis, Pain, Fatigue. By volume, the top reported reactions are: Off Label Use (38,502 reports), Drug Ineffective (33,161 reports), Rheumatoid Arthritis (19,544 reports). These figures reflect FDA adverse event reports and may not represent the true incidence rate of these side effects in all patients taking Rituximab.
Out of 201,540 classified reports, 179,719 (89.2%) were classified as serious and 21,821 as non-serious. The FDA classifies an event as "serious" if it results in death, hospitalization, disability, or other medically significant outcomes. A higher serious-event ratio warrants closer attention but does not necessarily mean the drug is unsafe.
Adverse event reports for Rituximab break down by patient sex as follows: Female: 92,649, Male: 65,505, Unknown: 1,768. This distribution reflects reporting patterns rather than actual risk differences between groups. Reporting rates can be influenced by prescribing patterns, disease demographics, and reporting behavior.
The most frequently reported age groups for Rituximab adverse events are: age 65: 3,905 reports, age 43: 3,624 reports, age 60: 3,395 reports, age 44: 3,250 reports, age 67: 3,193 reports. Age-related reporting patterns can reflect both the demographics of the patient population and potential age-related susceptibility to certain side effects.
The primary manufacturer associated with Rituximab adverse event reports is Genentech, Inc.. Multiple manufacturers may produce generic versions of this drug. The manufacturer listed reflects the most frequently reported brand in FDA adverse event data.
Beyond the most common reactions, other reported adverse events for Rituximab include: Rash, Arthralgia, Infusion Related Reaction, Pneumonia, Drug Intolerance. Less common side effects can still be clinically significant. Patients should report any unusual symptoms to their healthcare provider.
You can report adverse events from Rituximab to the FDA through their MedWatch program at www.fda.gov/medwatch, by calling 1-800-FDA-1088, or by completing Form FDA 3500. Healthcare professionals, consumers, and manufacturers can all submit reports. Reporting helps the FDA monitor drug safety after approval.
Rituximab has a safety concern score of 85 out of 100 (high concern). This score is calculated from the ratio of serious to non-serious adverse events, the diversity of reported reactions, and the overall volume of reports relative to usage. High percentage of serious adverse events (89.2%) indicates significant safety concerns.
Key safety signals identified in Rituximab's adverse event data include: High incidence of serious infections, particularly pneumonia.. Frequent occurrence of infusion-related reactions.. Autoimmune disorders such as systemic lupus erythematosus and rheumatoid arthritis are reported.. These signals are derived from patterns in FDA reports and should be discussed with a healthcare provider for personalized assessment.
Rituximab can cause severe allergic reactions and infusion-related reactions. Patients should be monitored closely during and after administration. Always inform your healthcare provider about all medications, supplements, and over-the-counter drugs you are taking before starting Rituximab.
Patients should report any adverse reactions immediately to their healthcare provider. Follow all prescribed dosing and administration guidelines to minimize the risk of adverse events.
Rituximab has 743,156 adverse event reports on file with the FDA. A wide range of reactions reported, including infections, infusion-related reactions, and autoimmune disorders. The volume of reports for Rituximab reflects both the drug's usage level and the vigilance of the reporting community.
The FDA continues to monitor Rituximab for safety, and updates are regularly issued based on new data. For the most current regulatory information, check the FDA's drug labeling database or consult your pharmacist.
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