by Dr. Ken Tudor
We often don’t know that the medications we routinely use for our own ailments can be dangerous to our pets. A recent alert by the U.S. Food and Drug Administration is a sad reminder. The FDA reports that in the last several years three cats have died and two cats became very ill after exposure to their owner’s pain relief cream. The cream contained the non-steroidal anti-inflammatory drug (NSAID), flurbiprofen. The brand name is Ansaid. What is particularly frightening about these cases is that the exposure may have been as minimal as licking the owner’s skin where the medication was applied.
NSAID Toxicity in Cats
Most of the pain relief medications we use are NSAIDs and date back to the introduction of aspirin by the Bayer Company in 1899. Ibuprofen in Motrin and Advil and naproxen in Aleve are the more recent NSAIDs most people are familiar with. Acetaminophen in Tylenol, another pain reliever that is also toxic to pets, is not strictly speaking an NSAID because it has no anti-inflammatory properties. Most doctors classify it with NSAIDs because the side effects are very similar.
Flurbiprofen is a relatively new NSAID that is particularly effective in treating eye injuries in dogs and is effective for topical pain relief in humans.
What are the side effects of NSAIDs? If overdosed or given to sensitive patients, NSAIDs can cause severe gastrointestinal ulcerations, particularly in the stomach. They can also injure liver cells and kidney cells, resulting in the failure of these organs. Cats are particularly susceptible to kidney failure due to their unique liver function.
All medications in pets and humans are eventually cleared from the body. The dosing of a drug, once-a-day, twice-a-day, three-a-day, or more, is based on how long it takes to transform or eliminate the drug from the body. In the case of NSAIDs, the liver of dogs and humans transforms NSAIDs to less active chemicals that are then eliminated from the body in the urine. The livers in cats do not contain many of these transforming enzymes so the active form of the drug circulates in their bodies longer. This makes them susceptible to the side effects at much lower doses than for dogs and humans, particularly kidney failure. The dose necessary for kidney failure in cats varies with the type of NSAID. Throughout my veterinary career I have successfully treated chronic pain in cats with aspirin at a low dose given every three days without any problems.
Necropsies (animal equivalent of an autopsy) of the cats that died verified gastrointestinal and kidney damage consistent with NSAID toxicity. The deceased cats and ill cats came from two households where the owners used pain relief cream containing flurbiprofen. Apparently the toxic dose of flurbiprofen is quite low because the exposure may have been just from the cats licking their owners’-NSAISs skin. Investigators have not ruled out that the exposure may have been greater and due to access to tubes of the medication inadvertently left available to the cats.
This is a sad and unfortunate story, but it should be a reminder for us to be more careful with our medications in homes with pets. And also remember that it is not just medications that may be harmful. Access to chocolate candy and sugarless gum containing xylitol can be equally as dangerous to our pets.
Dr. Ken Tudor
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