Recently a client named Sandra contacted me after she inadvertently poisoned her cat, Slinky by giving her Tylenol which contains Acetaminophen. Acetaminophen is highly toxic to cats and should never be administered.
Needless to say, Sandra was riddled with guilt over Slinky’s death.
Please don’t make the same mistake Sandra made.
A quick call to the veterinarian’s office could have prevented this tragedy from occurring…
Never give your animals any over the counter medication without consulting with your veterinarian. Below are some medications that have been known to be safe for either cats or dogs but read carefully. Some are not safe for cats.
Tylenol- NOT SAFE FOR CATS 
SAFE FOR DOGS - Under veterinarian care only
This seemingly safe drug used in humans for headaches and fever, can actually be deadly to your cat.
Why?
Cats have an unusual metabolism in their liver. When Tylenol is eaten, it is taken by the bloodstream to the liver. In the cat, the liver metabolizes or breaks down Tylenol into separate components which are actually toxic to the cat. In other species these components are further broken down by the liver into non-toxic substances.
But the cat lacks the necessary enzymes to continue this breakdown process. These end products of Tylenol breakdown are so toxic to the cat that death is the typical outcome.
Source: ASPCA, Dr. Jon
Ibuprofen is an NSAID (non-steroidal anti-inflammatory drug). Ibuprofen goes by several brand names, such as Advil and Motrin.
Ibuprofen should be used only as directed by your veterinarian for dogs.
Avoid administering Ibuprofen to cats. Source: VMA, Dr Jon
Aspirin - CAN BE SAFE FOR CATS AND DOGS
Check with your vet first!

These are the most commonly used drugs today classified as NSAIDS (Non-steroidal anti-inflammatory drugs), and are used for pain relief, and sometimes relief of inflammation in both dogs and cats. Once again, cats tend to metabolize (or break down) the aspirin products more slowly than dogs or humans, so dosage is usually done on an every other day basis in the cat. As with any NSAID, stomach upset can be a commonly seen side effect, so discontinuing the drug if vomiting occurs is recommended.
Typically, your veterinarian may recommend buffered aspirin, or more effective, Ascriptin. This form of aspirin contains Maalox, which helps to coat the stomach lining, and prevent irritation associated with aspirin products. Long term usage of aspirin, may also result in complications with the normal clotting of blood. Therefore, discontinuation of all aspirin products prior to any surgery is highly recommended.
Pepto Bismol - NOT SAFE FOR CATS 
SAFE FOR DOGS
Commonly recommended for our pets for stomach upset or diarrhea, Pepto-Bismol should only be used in the dog, as it can not be given daily to the cat. Perhaps the one benefit of Pepto-Bismol, is that of coating the stomach, and perhaps alleviating some symptoms of nausea. As for diarrhea, there seems to be little Pepto-Bismol can do.
Kaopectate - NOT SAFE FOR CATS
SAFE FOR DOGS
This too has been used in our pets for stomach upset or diarrhea. Some veterinarians swear by its effect, yet to date, little has been shown to its effectiveness in clinical studies. Recommended only for use in the dog.
Imodium AD - SAFE FOR CATS & SAFE FOR DOGS

This anti-diarrhea medication is useful in both dogs and cats. It seems to work better with small intestinal diarrhea and is available in both tablet and liquid form. Check with your veterinarian if your pet could take this drug, and at what dosage.
Pepcid AC- NOT SAFE FOR CATS
SAFE FOR DOGS
Is a useful drug for vomiting in the dog. Designed as an antacid, Pepcid AC decreases the acid secretion in the stomach, thereby alleviating associated discomfort and nausea. Check with your veterinarian if you pet could take this drug and at what dosage.
If you suspect your animal has ingested something it shouldn’t contact your veterinarian immediately and/or the Animal Poison Control Center