Fluorouracil is an anti-metabolite chemotherapy agent that targets quickly growing cells. Physicians prescribe the drug to treat various skin conditions in people, such as warts, superficial basal and squamous cell carcinomas, actinic or solar keratoses, and vitiligo. Fluorouracil is sold under the brand names Carac, Efudex, Tolak, and Fluoroplex, and under the generic name, Fluorouracil Cream USP, 5%.
FDA has received reports of serious illnesses and deaths in pets associated with prescription fluorouracil for use on people’s skin. Most pets are exposed accidentally, usually when they chew on and puncture a tube of the medicine or lick skin where their owner has just applied the medicine. Because this medicine is harmful to pets, FDA asked the manufacturers of approved fluorouracil topical creams and solutions to add new information to the medicine’s containers and tubes, warning pet owners about the potential dangers of fluorouracil to pets.
You can find more information about fluorouracil, signs of fluorouracil toxicity, and ways to prevent accidental pet exposure to fluorouracil in the following articles for pet owners, veterinarians, and health care providers (including physicians and pharmacists).
CVM Drug Safety Communication: Fluorouracil Products Used on People's Skin Can Cause Serious Reactions in Pets
Don't Expose Pets to Prescription Topical Fluorouracil Medicine for People
What Veterinarians, Health Care Providers, and Pharmacists Should Know to Prevent Pet Exposure to Prescription Topical Fluorouracil