Tolakfluorouracil
According to the FDA label: Tolak (fluorouracil) Cream is indicated for the topical treatment of actinic keratosis lesions of the face, ears, and/or scalp. Tolak (fluorouracil) Cream, 4%, is a nucleoside metabolic inhibitor indicated for the topical treatment of actinic keratosis lesions of the face, ears, and scalp ( 1 ).
74,177 adverse event reports submitted to the FDA (2004–2026)
Top Reported Adverse Events
The most frequently reported events in association with Tolak 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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Diarrhoea 6,782 reports
Loose or watery bowel movements, often frequent. Also spelled diarrhea in American English.
Full definition in the glossary → See all drugs reporting this event →Neutropenia 5,072 reports
A low level of neutrophils, a type of white blood cell that fights infection.
Full definition in the glossary →Nausea 4,799 reports
The feeling of sickness in your stomach that often comes before vomiting.
Full definition in the glossary → See all drugs reporting this event →Vomiting 3,874 reports
Throwing up the contents of the stomach.
Full definition in the glossary → See all drugs reporting this event →Off Label Use 3,414 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 →Neuropathy Peripheral 3,225 reports
Damage to the nerves outside the brain and spinal cord, often causing numbness, tingling, or pain in the hands and feet.
Full definition in the glossary →Disease Progression 3,181 reports
A report that the underlying condition being treated got worse over time. This describes the course of the illness, not necessarily an effect of the drug.
Full definition in the glossary →Fatigue 3,022 reports
Extreme tiredness or lack of energy that does not improve with rest.
Full definition in the glossary → See all drugs reporting this event →Pyrexia 2,980 reports
The medical term for fever, meaning a raised body temperature.
Full definition in the glossary → See all drugs reporting this event →Thrombocytopenia 2,906 reports
A low level of platelets, the blood cells that help with clotting.
Full definition in the glossary →Febrile Neutropenia 2,826 reports
A fever occurring together with a low level of neutrophils, a type of infection-fighting white blood cell. It is taken seriously because infection is harder to fight when these cells are low.
Full definition in the glossary →Asthenia 2,504 reports
Physical weakness or lack of strength.
Full definition in the glossary →Anaemia 2,468 reports
A condition where there are too few healthy red blood cells to carry enough oxygen, often causing tiredness and paleness. Also spelled anemia in American English.
Full definition in the glossary → See all drugs reporting this event →Drug Ineffective 2,138 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 →Malignant Neoplasm Progression 2,078 reports
A report that a cancer grew or spread. This describes the course of the illness, not necessarily an effect of the drug. Malignant neoplasm is the medical term for a cancerous growth.
Full definition in the glossary →
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 |
|---|---|
| Male | 34,900 |
| Female | 28,569 |
| Unknown | 816 |
By Age Group
View age group data as a table
| Age group | Reports |
|---|---|
| 0-17 | 1,702 |
| 18-34 | 1,504 |
| 35-49 | 7,200 |
| 50-64 | 20,366 |
| 65-74 | 16,895 |
| 75+ | 7,038 |
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 Tolak. 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 | 43,969 |
| Hospitalization | 29,927 |
| Death | 10,605 |
| Life-Threatening | 5,665 |
| Non-Serious | 3,746 |
| Disability | 1,330 |
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 Tolak. 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 |
|---|---|
| 2004 | 1,696 |
| 2005 | 1,686 |
| 2006 | 1,390 |
| 2007 | 1,586 |
| 2008 | 1,848 |
| 2009 | 1,814 |
| 2010 | 1,691 |
| 2011 | 2,337 |
| 2012 | 2,861 |
| 2013 | 2,240 |
| 2014 | 1,875 |
| 2015 | 2,381 |
| 2016 | 2,755 |
| 2017 | 3,205 |
| 2018 | 4,848 |
| 2019 | 5,099 |
| 2020 | 4,268 |
| 2021 | 4,267 |
| 2022 | 5,739 |
| 2023 | 6,336 |
| 2024 | 6,004 |
| 2025 | 6,702 |
| 2026 (partial) | 1,549 |
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 Tolak
In FDA adverse event reports that mention Tolak, these medications appeared most often in the same report.
- Oxaliplatin (32,390 reports)
- Bevacizumab (15,946 reports)
- Leucovorin (10,851 reports)
- Cisplatin (7,492 reports)
- Cetuximab (6,043 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