Is Fluorouracil (5-FU) safe for babies and kids?
High risk for kidsInfants have immature drug-metabolizing enzymes (CYP450 ontogeny), reduced renal clearance, and different volume of distribution. Accidental exposure or breast milk transfer of Fluorouracil (5-FU) poses heightened risk.
What is fluorouracil (5-fu)?
Also known as: 5-Fluorouracil, fluorouracil, Efudex, Fluracil.
- CAS number
- 51-21-8
- Molecular formula
- C4H3FN2O2
- Molecular weight
- 130.08 g/mol
- SMILES
- C1=C(C(=O)NC(=O)N1)F
- PubChem CID
- 3385
Risk for babies
High riskInfants have immature drug-metabolizing enzymes (CYP450 ontogeny), reduced renal clearance, and different volume of distribution. Accidental exposure or breast milk transfer of Fluorouracil (5-FU) poses heightened risk.
Neonates and infants up to 12 months have incomplete blood-brain barrier development, immature Phase I/II metabolic enzymes (particularly CYP3A4, UGT1A1), and higher gastrointestinal permeability. Equivalent doses produce higher internal concentrations and longer residence times.
Risk for pregnant and nursing people
High riskFluorouracil (5-FU) poses pregnancy risk through potential teratogenicity, altered pharmacokinetics (increased blood volume, changed CYP activity), and placental transfer. FDA pregnancy category should be evaluated.
Known reproductive toxicant (GHS H360) or confirmed endocrine disruptor. Placental transfer is presumed. Fetal exposure during critical developmental windows may cause structural malformations, growth restriction, or functional deficits.
Regulatory consensus
1 regulatory bodyhas classified Fluorouracil (5-FU).
| Agency | Year | Classification | Notes |
|---|---|---|---|
| Regulatory Framework | — | Regulated as pharmaceutical (FDA/EMA); not typically classified under industrial chemical regulations |
Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.
Where kids encounter fluorouracil (5-fu)
- Consumer Products — pharmaceutical/industrial use
Safer alternatives
Lower-risk approaches that achieve a similar outcome to Fluorouracil (5-FU):
-
Alternative drug class; Non-pharmacological therapy; Lowest effective dose
Trade-offs: Direct chemical substitution requires verification that the replacement does not introduce new hazards (regrettable substitution). Conduct full hazard assessment of proposed alternative before adoption.Relative cost: 1.2-2×
Frequently asked questions
Is fluorouracil (5-fu) safe for kids?
Infants have immature drug-metabolizing enzymes (CYP450 ontogeny), reduced renal clearance, and different volume of distribution. Accidental exposure or breast milk transfer of Fluorouracil (5-FU) poses heightened risk.
What products contain fluorouracil (5-fu)?
Fluorouracil (5-FU) appears in: pharmaceutical/industrial use (Consumer products).
What should I do if my child is exposed to fluorouracil (5-fu)?
Minimize infant exposure through source control. For breastfeeding mothers: reduce maternal exposure. For formula-fed infants: use certified low-migration bottles and verified water sources. Consult pediatrician regarding any concerns.
See Fluorouracil (5-FU) in the baby app
Look up products containing fluorouracil (5-fu), compare to alternatives, and explore the full data record.
Open in baby View raw API dataSources (1)
- PubChem (2026) — database
Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →