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
Safety
CBC at nadirGI toleranceNeurological statusEnsure NO cat contact with treated dog or excreta
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.
References
References
Textbooks & handbooks
- Plumb, D.C. Plumb's Veterinary Drug Handbook. 10th ed., Wiley-Blackwell, 2023.
- Vail, D.M., Thamm, D.H., & Liptak, J.M. (eds.). Withrow & MacEwen's Small Animal Clinical Oncology. 6th ed., Saunders/Elsevier, 2020.
- Riviere, J.E., & Papich, M.G. (eds.). Veterinary Pharmacology and Therapeutics. 10th ed., Wiley-Blackwell, 2018.
- National Research Council. Nutrient Requirements of Dogs and Cats. National Academies Press, Washington DC, 2006.
- The Merck Veterinary Manual. Merck & Co., Online edition. https://www.merckvetmanual.com/
Clinical guidelines & consensus
- Fletcher, D.J., Boller, M., Brainard, B.M., et al. "RECOVER Evidence and Knowledge Gap Analysis on Veterinary CPR." Journal of Veterinary Emergency and Critical Care, 2012;22(S1):S102–S131.
- American Animal Hospital Association. 2018 AAHA Diabetes Management Guidelines for Dogs and Cats. AAHA Press.
Journals & peer-reviewed studies
- Hogan, D.F., Fox, P.R., Jacob, K., et al. "Secondary prevention of cardiogenic arterial thromboembolism in the cat: The FAT CAT study." Journal of Veterinary Cardiology, 2015;17(Suppl 1):S306–S317.
- Boswood, A., Häggström, J., Gordon, S.G., et al. "Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study — A Randomized Clinical Trial." Journal of Veterinary Internal Medicine, 2016;30(6):1765–1779.
- ASPCA Animal Poison Control Center. Toxicology and Poison Management Guidelines. American Society for the Prevention of Cruelty to Animals. https://www.aspca.org/pet-care/animal-poison-control
Regulatory & approvals
- Central Drugs Standard Control Organisation (CDSCO), Government of India. Veterinary Drug Approval Registry, 1969–2026. Directorate General of Health Services. https://cdsco.gov.in/
Databases
- Washington State University, College of Veterinary Medicine. Veterinary Clinical Pharmacology Laboratory (VCPL) — MDR1 Multidrug Sensitivity Database. https://vcpl.vetmed.wsu.edu/
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 →