5-Fluorouracil Toxicity (for Human Use) in Pets

Abstract

5-Fluorouracil (5-FU) has high toxicity to pets. Given its mechanism of action as an antineoplastic metabolite that interferes with DNA synthesis, its accidental oral consumption creates a thymine deficiency that can be lethal for animals.

If a container of topical 5-FU is left in areas of the home accessible to pets, pets may chew on the container and ingest the medication. This accidental exposure causes disruption of RNA synthesis, and inhibits the animal's DNA replication and repair enzymes.