This grade answers one narrow question: how strong is the public evidence and safety record behind this drug, and how clean is its money trail and court record? It is not a verdict on whether the drug is right for you.
WARNING: SERIOUS ADVERSE REACTIONS OR DEATH IN PATIENTS WITH COMPLETE DPD DEFICIENCY Increased Risk of Serious Adverse Reactions or Death in Patients with Complete DPD Deficiency Test patients for genetic variants of DPYD prior to initiating fluorouracil unless immediate treatment is necessary. Avoid use of fluorouracil in patients with certain homozygous or compound heterozygous DPYD variants that result in complete DPD deficiency [see Warnings and Precautions (5.1)] . WARNING: SERIOUS ADVERSE REACTIONS OR DEATH IN PATIENTS WITH COMPLETE DPD DEFICIENCY, See full prescribing information for complete boxed warning Serious adverse reactions or death may occur in patients with complete DPD deficiency. Test patients for genetic variants of DPYD prior to initiating fluorouracil unless immediate treatment is necessary. Avoid use of fluorouracil in patients with certain homozygous or compound heterozygous DPYD variants that result in complete DPD deficiency. (2.1, 5.1)
Listed on the WHO Model List of Essential Medicines: a global expert panel judged it among the medicines a health system should always have, on evidence of value, not marketing.
Fluorouracil Injection is indicated for the treatment of patients with: Fluorouracil Injection is a nucleoside metabolic inhibitor indicated for the treatment of patients with Adenocarcinoma of the Colon and Rectum ( 1.1 ) Adenocarcinoma of the Breast ( 1.2 ) Gastric Adenocarcinoma ( 1.3 ) Pancreatic Adenocarcinoma ( 1.4 ) 1.1 Adenocarcinoma of the Colon and Rectum 1.2 Adenocarcinoma of the Breast 1.3 Gastric Adenocarcinoma 1.4 Pancreatic Adenocarcinoma
None. None ( 4 )
Cardiotoxicity: Fluorouracil can cause cardiotoxicity, including angina, myocardial infarction/ischemia, arrhythmia, and heart failure. Withhold fluorouracil for cardiac toxicity. ( 5.2 ) Hyperammonemic Encephalopathy: Altered mental status, confusion, disorientation, coma, or ataxia with elevated serum ammonia level can occur within 72 hours of initiation of fluorouracil. Withhold fluorouracil and initiate ammonia-lowering therapy. ( 5.3 ) Neurologic Toxicity: Fluorouracil can cause acute cerebellar syndrome, confusion, disorientation, ataxia, or visual disturbances. Withhold fluorouracil for neurologic toxicity. ( 5.4 ) Diarrhea: Fluorouracil can cause severe diarrhea. Withhold fluorouracil for severe diarrhea until resolved. ( 5.5 ) Palmar-Plantar Erythrodysesthesia (Hand-Foot Syndrome): Fluorouracil can cause hand-foot syndrome. If severe, discontinue fluorouracil until resolved or decreased to Grade 1, then resume at a reduced dose. ( 5.6 ) Myelosuppression: Fluorouracil can cause severe and fatal myelosuppression. Withhold fluorouracil until severe myelosuppression resolves, then resume at a reduced dose. ( 5.7 ) Mucositis: Fluorouracil can cause severe mucositis. Discontinue...
The following adverse reactions are discussed in more detail in other sections of the labeling: Serious Adverse Reactions or Death from Dihydropyrimidine Dehydrogenase (DPD) Deficiency [see Warnings and Precautions (5.1) ] Cardiotoxicity [see Warnings and Precautions (5.2) ] Hyperammonemic encephalopathy [see Warnings and Precautions (5.3) ] Neurologic toxicity [see Warnings and Precautions (5.4) ] Diarrhea [see Warnings and Precautions (5.5) ] Palmar-plantar erythrodysesthesia (hand-foot syndrome) [see Warnings and Precautions (5.6) ] Myelosuppression [see Warnings and Precautions (5.7) ] Mucositis [see Warnings and Precautions (5.8) ] Increased risk of elevated INR when administrated with warfarin [see Warnings and Precautions (5.9) ] To report SUSPECTED ADVERSE REACTIONS, contact Meitheal Pharmaceuticals, Inc. at 1-844-824-8426 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.2 Postmarketing Experience The following adverse reactions have been identified during postapproval use of fluorouracil. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship ...
Boxed Warning 11/2025 Dosage and Administration, Evaluation and Testing for DPD Deficiency Before Initiating Fluorouracil ( 2.1 ) 11/2025 Warnings and Precautions, Serious Adverse Reactions or Death from Dihydropyrimidine Dehydrogenase (DPD) Deficiency ( 5.1 ) 11/2025
Source: FDA SPL label for Fluorouracil (Meitheal Pharmaceuticals Inc.), effective 20260408. Full label on DailyMed.
These are counts of reports people filed, not rates of harm. Anyone can file one, and nobody checks whether the drug was the cause. Millions of doses are taken for every report sent, so the useful part is how this drug compares with the average across all drugs.
| 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 |
|---|---|---|---|---|---|---|---|
| 7,549 | 6,280 | 5,377 | 5,821 | 6,385 | 6,062 | 6,768 | 3,338 |
23,677 reports blaming this drug for every million Medicare prescriptions filled, which is 8.6× the typical drug on this site. (16,071 reports in 2024–2026, against 678,749 Medicare fills in one year. This is the one number here that accounts for how many people take the drug.)
Source: the FDA's Adverse Event Reporting System (FAERS). Reports are voluntary and unverified. Drugs that are prescribed a lot, in the news, or in lawsuits attract more reports, so the percentages are compared with the whole database to correct for that partly, not fully.
| Date | Class | Firm | Reason |
|---|---|---|---|
| 06/2019 | Class I | Fresenius Kabi USA, LLC | Presence of Particulate Matter; glass particulates |
| 11/2012 | Class II | Taro Pharmaceuticals U.S.A., Inc. | Product Lacks Stability: Out-of-specification (OOS) results were observed for assay and description in retain samples. |
Class I = reasonable probability of serious harm. Class II = temporary or reversible harm. Class III = unlikely to harm. Most generic recalls are manufacturing or labeling defects for one lot, not a verdict on the molecule.
Counts measure how much evidence exists and how transparent it is, not how big the benefit is. For that, ask your prescriber: if 100 people like me took this, how many would get better because of it, and how many would be harmed? (Doctors call these the "number needed to treat" and "number needed to harm.") It differs by condition and is the number drug ads leave out. Sources: PubMed, ClinicalTrials.gov.
In 2024, drug companies reported $15,699 in payments to US physicians and hospitals tied to this drug across 206 transactions (Tolak $15,699).
No pending federal MDL names this drug or its brands.
Not named in any federal pharmaceutical settlement of $100M or more on record.
Sources: CMS Open Payments (Sunshine Act); Judicial Panel on Multidistrict Litigation pending docket list; DOJ settlements as tabulated on Wikipedia with links to the primary record. State-court and individual suits are not included.
| Product | Fills | $/fill |
|---|---|---|
| Fluorouracil | 677,948 | $67 |
| Efudex | 789 | $59 |
| Tolak | 12 | $40 |
Same ATC pharmacological class, graded ones first, best grade at the top. Being in the same class does not make them interchangeable for your condition; it makes them worth asking about.