In terms of a cat’s exposure to hazardous substances, poisoning by human medications tops the list. Human therapeutic drugs were the most common cause of cat poisoning. These are prescription or over-the-counter medications used to treat an illness or injury in humans.
“Most calls were related to drugs [and most of the drugs were for humans], followed by household products, food, pesticides, plants, and others” (Kansas State Uni)
Most poisonings by human drugs take place during the summer months of June, July and August. The five states of the USA which generated the highest number of calls regarding poisoning of cats and dogs over the period 2009 to 2012 are: California, Florida, Illinois, Kansas and Texas.
The vast majority of exposures to hazardous substances for cats were via the oral route which bearing in mind the opening sentence means the ingestion of human therapeutic drugs in the form of pills.
Kansas keeps a nice record of drug poisoning of cats and other substances which were reported at Kansas State University from 2009 to 2012. The data informs us that human drugs are top of the list at about a third of all cases followed by household products at about 15% of cases.
Among drugs, human drugs are far more common involved in cat poisonings compared to veterinary drugs in Kansas at 91.2 and 8.8% respectively. I’m referring to Kansas because they have a nice study on this subject but I feel fairly confident that other states would have similar results.
Typically, with respect to human drugs, non-steroidal anti-inflammatory drugs including aspirin, ibuprofen and acetaminophen form the largest group. Vitamins, supplements and minerals are the next most common drug hazard to cats followed by the following in descending order: antimicrobials, anxiolytics and antidepressants, birth-control medications, hormones, tranquilizers and sleeping aids, blood pressure medications, antihistamines, anthelmintics, decongestants, pain relievers and muscle relaxants, diabetes medications, laxatives, Parkinson’s disease medications, local anesthetics, antiseptics and disinfectants, urinary tract medications, bronchodilators, cholesterol-lowering agents and finally unspecified “others”.
The conclusion is that accidental ingestion of human pills are a common cause of poisoning in domestic cats. Many cat owners give over-the-counter medications to their cats without veterinary supervision or advice to treat a range of symptoms because they believe it works for their cat as it works for them. This is untrue. Cats are highly sensitive to many medications and drugs given to cats in human dosages are nearly always toxic. Some drugs cannot be given to cats under any circumstances.
Drugs such as Ibuprofen or Advil and Tylenol are very toxic to cats. This is because they do not have the necessary enzymes to detoxify and eliminate the drug. I’m told that cats lack the liver enzyme glucoronyl transferase which breaks down drugs so that they can be metabolized. This leads to the accumulation of substances toxic to cats which are left behind once the drug has been metabolized. Symptoms include weakness, vomiting, salivation and abdominal pain.
It goes without saying, but I’ll say it, that cat owners must immediately respond to a suspected poisoning by human drugs. They should call their veterinarian urgently and seek instructions. A specific antidote may be available and you can also call a Poison Control Center.
The bottom line, and it is quite a shocking statistic, is that in terms of cat drug poisoning it is far more common for medications for humans to poison cats in the home than it is for veterinary medications. The reason, as mentioned is probably twofold (1) cat owners give their cats over-the-counter human medication i.e. therapeutic drugs and (2) curious cats are attracted to pills lying around the floor which they might play with and try to eat.