Pyrimidine analog converted to active metabolites that inhibit thymidylate synthase (blocking DNA synthesis) and incorporate into RNA (disrupting RNA processing). S-phase specific.
At a glance
Class
Antimetabolite (Chemotherapy)
Schedule
Prescription (Chemotherapy)
Storage
Store at room temperature; protect from light; chemotherapy precautions; KEEP AWAY FROM CATS
Dosing
Used for various carcinomas
Frequency
Weekly or per protocol
NEVER use 5-FU in cats — even small topical exposure causes fatal neurotoxicity
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet.
Find a vet near you →Safety
CBC at nadirGI toleranceNeurological statusEnsure NO cat contact with treated dog or excreta
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet.
Find a vet near you →Interactions
No documented interactions.
FAQs
Frequently asked questions
›What is Fluorouracil (5-FU)?
Fluorouracil (5-FU) is a antimetabolite (chemotherapy) used in pets. Pyrimidine analog converted to active metabolites that inhibit thymidylate synthase (blocking DNA synthesis) and incorporate into RNA (disrupting RNA processing). S-phase specific.
›What is Fluorouracil (5-FU) used for in pets?
Fluorouracil (5-FU) is used in veterinary medicine for: Used for various carcinomas; NEVER use 5-FU in cats — even small topical exposure causes fatal neurotoxicity .
›What is the Fluorouracil (5-FU) dose for dogs?
For dogs, Fluorouracil (5-FU) is typically dosed as follows — Used for various carcinomas: 150 mg/m² IV Weekly or per protocol. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Fluorouracil (5-FU) dose for cats?
For cats, Fluorouracil (5-FU) is typically dosed as follows — NEVER use 5-FU in cats — even small topical exposure causes fatal neurotoxicity : undefined undefined N/A N/A. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›Does Fluorouracil (5-FU) need a prescription?
Yes. Fluorouracil (5-FU) is a prescription medication and should only be administered under veterinary supervision.
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet.
Find a vet near you →References
References
The PetCare.AI drug reference is built from 13 authoritative sources cited across 580 drug monographs.
Textbooks & handbooks — 5
- Plumb's Veterinary Drug Handbook
- Withrow & MacEwen's Small Animal Clinical Oncology
- Merck Veterinary Manual
- NRC Nutrient Requirements of Dogs and Cats
- Veterinary Pharmacology and Therapeutics (Riviere & Papich)
Clinical guidelines & consensus — 4
- ASPCA Animal Poison Control Center Guidelines
- AAHA Diabetes Management Guidelines
- ASPCA Poison Control Guidelines
- RECOVER CPR Guidelines
Journals & peer-reviewed studies — 2
- EPIC Study (J Vet Intern Med 2016)
- JVIM FAT CAT Study
Regulatory & approvals — 1
- CDSCO Veterinary Drug Approval Registry (1969–2026)
Databases — 1
- Washington State University VCPL MDR1 Database