85/100 · Critical
Manufactured by Bausch Health US, LLC
Fluorouracil Adverse Events: High Seriousness and Diverse Reactions
124,552 FDA adverse event reports analyzed
Last updated: 2026-05-12
FLUOROURACIL is a medication tracked in the FDA Adverse Event Reporting System (FAERS), manufactured by Bausch Health US, LLC. Based on analysis of 124,552 FDA adverse event reports, FLUOROURACIL 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 FLUOROURACIL include DIARRHOEA, NEUTROPENIA, NAUSEA, VOMITING, OFF LABEL USE. This page provides a comprehensive breakdown of reported side effects, safety signals, patient demographics, and AI-powered safety analysis for FLUOROURACIL.
Fluorouracil 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 124,552 adverse event reports for this medication, which is primarily manufactured by Bausch Health Us, Llc.
The most commonly reported adverse events include Diarrhoea, Neutropenia, Nausea. Of classified reports, 94.6% were designated as serious by the FDA, meaning they involved hospitalization, disability, or other significant medical outcomes. Fluorouracil is associated with a high number of serious adverse events, including death and severe infections.
The drug has a wide range of reactions, indicating potential for diverse side effects. Neutropenia and thrombocytopenia are among the most common reactions, highlighting blood-related risks.
Patients taking Fluorouracil should monitor for the commonly reported side effects and contact their healthcare provider if they experience any unusual symptoms. Fluorouracil can interact with other drugs, such as those affecting hematopoiesis, and may exacerbate existing conditions. Warnings include monitoring for hematological and respiratory complications. This analysis is based on voluntary FDA adverse event reports and should not replace professional medical advice.
Fluorouracil received a safety concern score of 85/100 (high concern). This is based on a 94.6% serious event ratio across 73,484 classified reports. The score accounts for 124,552 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: Male: 34,409, Female: 28,451, Unknown: 817. The most frequently reported age groups are age 65 (1,848 reports), age 67 (1,847 reports), age 70 (1,808 reports). These demographics reflect reporting patterns and may not represent the full patient population.
Out of 73,484 classified reports for FLUOROURACIL:
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.
Fluorouracil can interact with other drugs, such as those affecting hematopoiesis, and may exacerbate existing conditions. Warnings include monitoring for hematological and respiratory complications.
If you are taking Fluorouracil, here are important things to know. The most commonly reported side effects include diarrhoea, neutropenia, nausea, vomiting, off label use. While many of these may be mild and temporary, you should contact your healthcare provider if any symptoms are severe or persistent. Monitor closely for signs of infection, particularly neutropenia and thrombocytopenia, and report any symptoms immediately. Follow prescribed dosing and administration guidelines to minimize the risk of adverse reactions. 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 closely monitors Fluorouracil for safety, and the drug is subject to ongoing review due to its serious adverse event profile.
The FDA has received approximately 124,552 adverse event reports associated with Fluorouracil. 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 Fluorouracil include Diarrhoea, Neutropenia, Nausea, Vomiting, Off Label Use. By volume, the top reported reactions are: Diarrhoea (6,692 reports), Neutropenia (4,988 reports), Nausea (4,750 reports). These figures reflect FDA adverse event reports and may not represent the true incidence rate of these side effects in all patients taking Fluorouracil.
Out of 73,484 classified reports, 69,500 (94.6%) were classified as serious and 3,984 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 Fluorouracil break down by patient sex as follows: Male: 34,409, Female: 28,451, Unknown: 817. 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 Fluorouracil adverse events are: age 65: 1,848 reports, age 67: 1,847 reports, age 70: 1,808 reports, age 68: 1,798 reports, age 62: 1,757 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 Fluorouracil adverse event reports is Bausch Health Us, Llc. 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 Fluorouracil include: Disease Progression, Neuropathy Peripheral, Fatigue, Pyrexia, Thrombocytopenia. 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 Fluorouracil 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.
Fluorouracil 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. Fluorouracil is associated with a high number of serious adverse events, including death and severe infections.
Key safety signals identified in Fluorouracil's adverse event data include: Neutropenia and thrombocytopenia are key safety signals, indicating significant hematological risks.. Death and sepsis are serious outcomes reported, reflecting the severity of adverse reactions.. A diverse range of reactions, including pulmonary embolism and interstitial lung disease, suggest potential for severe respiratory issues.. These signals are derived from patterns in FDA reports and should be discussed with a healthcare provider for personalized assessment.
Fluorouracil can interact with other drugs, such as those affecting hematopoiesis, and may exacerbate existing conditions. Warnings include monitoring for hematological and respiratory complications. Always inform your healthcare provider about all medications, supplements, and over-the-counter drugs you are taking before starting Fluorouracil.
Monitor closely for signs of infection, particularly neutropenia and thrombocytopenia, and report any symptoms immediately. Follow prescribed dosing and administration guidelines to minimize the risk of adverse reactions.
Fluorouracil has 124,552 adverse event reports on file with the FDA. The drug has a wide range of reactions, indicating potential for diverse side effects. The volume of reports for Fluorouracil reflects both the drug's usage level and the vigilance of the reporting community.
The FDA closely monitors Fluorouracil for safety, and the drug is subject to ongoing review due to its serious adverse event profile. For the most current regulatory information, check the FDA's drug labeling database or consult your pharmacist.
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