A 63-year-old man with a history of squamous cell carcinoma and actinic keratoses was seen for an initial visit for dermatologic evaluation. Physical examination revealed multiple actinic keratoses diffusely distributed across his face. Field treatment with fluorouracil, 5%, cream was recommended. The patient declined because when he had previously been treated with 5-fluorouracil, 5%, cream, his 2-kg Yorkshire Terrier had bitten the tube and shortly thereafter began vomiting and seizing. The Animal Poison Control Center (APCC) told him that fluorouracil cream is extremely toxic to dogs, and they recommended that he immediately take his animal to a local veterinary emergency care facility. At the facility, his dog became comatose and died several hours later. He feared he might accidentally expose another of his dogs to the medication.
Snavely NR, Snavely DA, Wilson BB. Toxic Effects of Fluorouracil Cream Ingestion on Dogs and Cats. Arch Dermatol. 2010;146(10):1195-1196. doi:10.1001/archdermatol.2010.289