Veterinary Q&A: Human meds can be toxic for pets

Originally posted on Tails of Seattle, The Seattle Times, by Neena Pellegrini, January 2012

Dr. Joe Musielak, an emergency-care veterinarian at Pilchuck Veterinary Hospital in Snohomish, says there is an emerging class of toxins: consumption of human medications by pets, especially pain meds. ... He answers this week's questions.

Question: Why can't dogs and cats be given over-the-counter human pain medications?

Answer: The problem with giving dogs and cats human pain meds, such as aspirin, Tylenol, and ibuprofen, is two fold.

First, most human medications are dosed for an adult human. Very few dogs and even fewer house cats weigh as much as an adult human. From the start, there is an overdose problem.

Second, cats and dogs are not humans. Their metabolism differs from ours in significant ways.

Cats, for example, cannot metabolize acetaminophen (the active ingredient in Tylenol) as we do. Tylenol exposure can be fatal to cats because acetaminophen eliminates the ability of red blood cells to carry oxygen to the rest of the body. This causes a death similar to suffocation.

A dog that chews up a bottle of ibuprofen, for example, may seem fine for a day or two. But then severe stomach ulceration and kidney failure may start. A pet's prognosis is much worse and a hospital stay and subsequent cost are greater if we wait until they show clinical symptoms with medications like ibuprofen.

Question: What about aspirin?

Answer: Dogs can take aspirin in low doses; however, there are much more effective pain relievers for dogs that are also safer.

Question: What kind of organ damage can these human medications cause when ingested by pets?

Answer: Pets can have significant -- even life-threatening -- kidney damage from ingesting human medications without showing any outward signs of trouble.

Pets with kidney failure can have a decreased amount of urine, an increased amount of urine or it can appear to be normal. Sometimes the kidneys are just getting rid of excess water in kidney failure and not removing waste products, which can build up to toxic levels.

For example, when a pet's blood values are elevated, at least 50 percent of the kidneys are likely damaged, something an owner wouldn't know without blood tests. When pets start to show symptoms of kidney failure (vomiting, loss of appetite, abnormal urination), at least 75 percent of the kidneys are likely damaged.

In some cases, with supportive care, the remaining healthy kidney tissue can improve in function and return to a level capable of sustaining life. Obviously, the greater the damage, the less chance the healthy tissue has of "regenerating."

Pets can also experience liver failure, intestinal ulcers or bleeding disorders from some of these medications.

Question: What about other kinds of human drugs?

Answer: We are starting to see more cases of pets ingesting their owners' antidepressant, anti-anxiety, bipolar disorder or attention deficit hyperactivity disorder (ADHD) medications.

In the case of ingestion, it is very important to let your veterinarian know what the medication is. "One of those little white pills that taste funny" isn't a particularly helpful description.

Most cases we see are accidental ingestion of these medications. The owner drops a pill on the floor, and the pet chases the rapidly moving object and scoops it up before anyone else can get it, thinking it's a treat.

We see pets that gobble up certain types of blood pressure medications that come in almost comatose; a single acetaminophen can kill a cat.

Question: Are there antidotes?

Answer: Sadly, there usually are not. Most of the time we do what is called "supportive care."

This may sound weak compared with the kind of antidotes we see in the movies (which are Hollywood antidotes), but supportive care is actually a very powerful form of treatment in these cases.

Because most of these medications do not have a specific antidote, we treat the symptoms or side effects, which often can be as dangerous as the main effect the medication has on the body.

Supportive care focuses on eliminating the toxin from the body as soon as possible to decrease the negative effects and quite often diluting the substance in the body with IV fluids.

Supportive care, if started as soon as possible, often has a good outcome for most accidental ingestions. It can be EXTREMELY helpful if we can get the pet to vomit up an intact pill (beware though, not all toxicities benefit from vomiting. Some toxicities are actually made worse when you induce vomiting).

For vomiting to be effective it must be induced before the substance leaves the pet's stomach and heads into the intestines. Dogs and cats empty their stomachs in the normal way relatively rapidly under normal circumstances. You only have about an hour or two at the most.

In some cases vomiting can almost eliminate long-term damage done to your pet. It becomes much more expensive and shortens your pet's life the longer the damage goes untreated.

"Waiting to see how the pet does overnight" usually causes much more heartache than prompt treatment.

Question: Should I call a veterinary poison-control hotline?

Answer: YES! Because there are so many of these medications on the market, your vet will often need to contact a hotline to find the recommended treatment, the statistics on how likely your pet is to survive the toxin, and how long the hospital stay may need to be.

If you call the poison-control hotline, make sure you write down the case number they give you. Your vet can use this case number to get additional information.

Located in Snohomish, PVH offers 24/7 emergency care: 360.568.9111. The ASPCA poison control number is 888.426.4435; reach Pet Poison Helpline at 855.764.7661.

Article updated 3.16.15