puppy and kitten2


Acetaminophen (Tylenol)

Human NSAID (Advil, Midol, Nuprin, Aleve)

Over the counter (OTC) medications are the 4th most common cause of poison exposure in small animals, either administered by owners who are unaware of their toxic effects in animals, or from pets eating dropped pills or chewing through medicine bottles.

Cats and dogs differ from humans in how they metabolize drugs; specifically, their livers utilize enzyme systems different from ours to process drugs.  Cats are especially sensitive to the toxic effects of the above drugs because their livers are extremely deficient in some of the enzyme pathways necessary to clear certain drugs from their bloodstream.  This buildup of drugs or their byproducts in the pet’s system may lead to destruction of blood cells, liver damage, kidney damage, and stomach and intestinal irritation and ulcers.

For example, which of the above pain killers would you think is safest in cats?  Would you reach for that dropper full of Baby Tylenol?  In fact, Acetaminophen has the narrowest margin of safety of the drugs listed above, and is deadly to cats, because it requires those exact enzymes lacking in cat livers to metabolize it.

“Well, Doc, I always heard a little baby aspirin couldn’t hurt anything.  Besides, my dog seems painful and I can’t get in to the vet until tomorrow.”

Whether regular, buffered, or enteric coated aspirin is given, it still enters the bloodstream, where it causes irreversible changes to the ability of platelets to clot the blood.  It also decreases blood flow to the stomach lining and kidneys, causing an increased risk of GI ulceration and kidney failure.  Even worse, its effectiveness as a pain killer is almost 100 times LESS than that of a prescription animal pain reliever such as Rimadyl or Deramaxx!

 “So what’s the difference between Advil and Rimadyl?  They’re both NSAIDs (NonSteroidal Anti-inflammatories), right?”

Newer classes of human NSAIDs were created to target pain receptors better, with fewer side effects than aspirin (the “original” NSAID).  The same is true in dogs and cats, but animal NSAIDs have been extensively researched and developed to be safe in animals: dog NSAIDs are made to be tolerated by dogs, at dosages that can be safely metabolized by the liver, and with metabolites that target pain receptors, sparing the GI tract and kidneys.  Cats have an even lower tolerance of these drugs, and must only be given cat-specific prescriptions.