The Food and Drug Administration (FDA) has issued a warning to clinicians, pharmacists, veterinarians and pet owners concerning the possibility of illness or death in pets exposed to thetopical cancer medication, Fluorouracil Cream USP 5% (5-FU).

The cream, which is also marketed under brand names Carac, Effudex and Fluoroplex, has been shown to be lethal to dogs if ingested. The FDA received reports of five dogs that died after ingesting the cream. In one case, a dog began vomiting and having a seizure two hours after ingestion, and died after 12 hours. In another case, a dog’s condition declined over three days and he was ultimately euthanized.  

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Although there have been no reports of cats ingesting Fluorouracil, the FDA indicated that they are also likely to be extremely sensitive to the cream. Pet owners are advised to remove all residue of cream from their hands before petting their dog or cat as the pet may ingest some medication when grooming itself.

Clinicians and pharmacists who prescribe and fill medications containing Fluorouracil are advised to inform patients to avoid exposing their pets to the medication.

Pet owners are recommended to:

  • Store all medications safely out of the reach of pets.
  • Safely discard or clean any cloth or applicator that may retain medication and avoid leaving any residues of the medication on hands, clothing, carpeting or furniture.
  • Consult with a healthcare professional on whether it is appropriate to cover the treated area.
  • If when using topical medications containing Fluorouracil a pet becomes exposed, consult a veterinarian immediately.
  • If a pet shows signs such as vomiting, seizing or other illness, seek immediate veterinary care for the pet and be sure to provide the details of the exposure.

The FDA asks that any adverse animal events be reported to them by sending the electronic form 1932a.