A new advisory by the US Food and Drug Administration (FDA) released in September 2022 states that the topical ointment, fluorouracil, also known as 5-FU or 5-fluorouracil, is found to be toxic to dogs.
There were several reports that dogs who had ingested the drug through licking had died of poisoning. Although no incidents involving cats have been reported yet, the FDA has cautioned everyone to keep the medicine away from all pets.
Dogs can be exposed to the drug by either licking the skin of someone who has applied the drug on their skin or through accidental chewing of the tubes or containers.
The Danger Of Fluorouracil To Dogs
Fluorouracil is a chemotherapy agent used to treat pre-cancerous and cancerous skin cells or basal cell carcinoma. It comes as a cream or solution that is applied to the skin to shrink cancerous growths and warts.
The drug is also used as an intravenous injection for the treatment of several types of cancer, including colorectal, stomach, breast, and cervical cancers. And, it is also found to be effective in treating some forms of cancer in horses.
Common brands of this drug include Efudex, Adrucil, Fluoroplex, Carac, and Tolak. The medication was first commercially used in 1962.
Because of these findings, the FDA advised manufacturers of this drug to add a label or wording on their product that it is fatal to pets. Many users of the drug, and also many dermatologists and veterinarians, are unaware that this drug can be deadly to animals.
A warning similar to the one written on a pack of cigarettes can be added like, “may be fatal if your pet licks or ingests. Avoid allowing pets to contact this tube or your skin where fluorouracil has been applied. Store and dispose of reach of pets.”
How To Avoid Accidental Ingestion?
The FDA gave some pointers on how to prevent any accidents in case you are using the drug for treatment. The simplest thing to do is to always store the medication in a secure place where your pets cannot reach it, like a medicine cabinet, and not on a bedside table or countertop.
It is also important to dispose of the empty container properly without it getting accidentally exposed in waste bins. You can also ask your doctor if it is alright to cover the treated area with gauze to prevent a dog from licking it.
In the event that you suspect your dog is suffering from fluorouracil poisoning, it is advised that you immediately visit an emergency veterinary facility. The effects of the drug are very rapid, with most dogs dying within a few hours upon exposure.