The Food and Drug Administration has put out a warning that just a small amount of the topical medicine fluorouracil can make a cat very sick and even result in a pet’s death if she licks it from your skin or manages to make her way into the dispensing tube. Fluorouracil is prescribed for people to treat warts, certain skin cancers, patches of scaly skin that could turn into cancer, and vitiligo. But ingested by cats, it can cause problems ranging from vomiting, seizures, and tremors to difficulty breathing and even death.
Because the medicine can be harmful, and even fatal, to cats and other pets, the FDA has asked manufacturers of the drug to put the following warning on labels:
“May be fatal if your pet licks or ingests.
Avoid allowing pets to contact this tube or your skin where [name of specific fluorouracil product] has been applied. Store and dispose out of the reach of pets.”
The drug is sold under the brand names Carac, Efudex, Tolak, and Fluoroplex. It is also sold under the generic name Fluorouracil Cream USP, 5%. But it is far from the only topical medicine that can cause harm to cats who like to lick their people, a common pastime for many pet felines.
Other drugs that pose a danger for cats who lick the skin of their human family members:
- Minoxidil. Used to combat hair loss, it can cause fluid to build up in a cat’s lungs and subsequently lead to heart failure.
- Flurbiprofen. An anti-inflammatory pain medicine often prescribed by physicians in the form of a topical cream to treat osteoarthritis, this drug can cause anemia and kidney failure in cats if they ingest it. The FDA warns that it takes only a very small amount.
Even a number of over-the-counter lotions have at least the potential to prove toxic to cats who lick them off their owners, causing nausea, vomiting, and diarrhea. These include steroid-based creams, such as those with short-acting hydrocortisone to treat itching; anti-fungal creams that some people use to treat conditions like nail fungus and athlete’s foot; triple-antibiotic ointments that you might use on a cut or other wound; sunscreen; antihistamine creams; and moisturizing lotions. Furthermore, topical hormonal replacements, such as estrogen creams, can cause signs of estrus (heat) or behavior changes in cats who lick and then ingest them.
Take precautionary measures
Always keep topical (and all medicines, for that matter) out of reach. In addition, throw away or wash anything used to apply the medicine, such as gloves or cotton-tipped applicators. Wash your hands well after applying the medicine, too. You don’t want to be petting or picking up your cat and leaving residue on her fur that she might then lick off. Finally, as much as you might find it adorable that your cat likes to lick you (although it could also irritate the skin after a while because cats have barbed tongues), do not let it happen when you have applied a topical cream or lotion that has not yet sunk into your skin. Better to have a frustrated cat than a very sick one, or worse.