Visiting Vet: Some human meds work for dogs, others definitely don’t

I don’t remember what kind of dog she was. Something medium-sized and short-haired, like a pointer. Let’s call her Sandi. I do recall how she hunched up with abdominal pain. Sandi had been vomiting at home all afternoon and now had explosive bloody diarrhea. The last time she upchucked, there had also been blood in the vomit, prompting her owner to seek after-hours emergency care. This condition is called hemorrhagic gastroenteritis (HGE), a term that describes the problem but doesn’t explain the cause.

“Has she had anything unusual to eat in the last 24 hours?” I asked, noting that Sandi seemed depressed and weak. Her owner shook his head. “Does she run loose where she might have gotten into garbage or compost?” I inquired, noting her capillary refill time was slow, indicating probable dehydration.

“No, she’s with me all the time,” her owner replied.

I hate when I can’t find a specific reason for an HGE case, but it happens frequently. This time the owner also happened to be a physician, increasing my self-imposed compulsion to find the source of the problem. “Any exposure to toxins or drugs?” I asked, as a rectal exam produced a scary blob of feces that looked more like raspberry jam than poop. The doctor was quiet for a moment. A long moment.

Pets sometimes get themselves into trouble ingesting things that are either illegal or potentially embarrassing to their owners — marijuana, amphetamines, prescription drugs that are being abused or that are for medical conditions which the human patients would prefer not to make public. I’ve been in this challenging situation before. Without knowing exactly what has been ingested, it’s harder to treat appropriately, but getting an uneasy owner to be forthcoming can be tough, too. I could see by his discomfiture there was something he wasn’t telling me. I asked again. “Any access to toxins or drugs?”

“She’s been kind of stiff lately,” he responded, sheepishly, “so I gave her some naproxen this morning.”

Naproxen is an NSAID. That’s a non-steroidal anti-inflammatory drug. NSAIDs are medications that contain neither corticosteroids (cortisone) nor opioids (narcotics). They are used to reduce pain without inducing sleepiness or being addictive. You probably have some in your medicine cabinet right now. Aspirin, ibuprofen, naproxen. These are all NSAIDs available over-the-counter under brand names like Bufferin, Advil, and Aleve. Lay people often think these drugs are interchangeable, but they are not, and a physician should know this. “How much did you give?” I sighed.

Although I never prescribe naproxen to dogs, theoretically the acceptable canine dose is 2 mg/kg every other day. Sandi weighed 55 pounds. That’s 25 kilograms. Let’s do the math. Two milligrams naproxen times 25 kilograms body weight gives us a recommended doggy dose of 50 mg. “I gave her one Aleve,” the owner said. In the doctor’s defense, that’s a normal dose for a person. In fact, people occasionally take two or three times that amount.

So what’s the big deal? How could one little Aleve hurt? Well, that one little Aleve contains 220 mg of naproxen, more than four times the recommended canine dose. In dogs, one little Aleve can cause vomiting, lethargy, anorexia, and gastric ulceration. In some cases, it can cause abdominal pain, depression, hemorrhagic vomit and diarrhea, even gastric perforation. At higher doses, it can cause kidney damage.

If the doctor had called immediately after giving Sandi the Aleve, we would have induced vomiting to get it out of her stomach, but it was too late for that now. The damage was done, the pill long gone, down into her intestines. Besides, she had obviously emptied her stomach naturally. “What now?” the doctor asked.

For many toxin ingestions, we give activated charcoal orally. This is kind of akin to the old home remedy of eating burnt toast. The charcoal molecules bind any remaining toxin in the gastrointestinal tract, preventing further absorption into the blood stream. For naproxen toxicity, charcoal is generally recommended, but Sandi’s gastrointestinal lining was already so inflamed there was a real risk her gut could perforate, in which case charcoal administration would be contraindicated. “Too late for charcoal,” I decided. Our main goal now would be to minimize any further damage to the lining of her gastrointestinal tract and provide sufficient supportive care for her to weather the storm. We treated with antacids, anti-vomiting medications, and gastric protectants.

“The amount you gave is below the level known to cause kidney damage,” I consoled the owner, “but we should get baseline blood work and monitor her over the next few days.” If he had given Sandi two tabs instead of one, there would be greater risk and I would have advised transfer to a 24-hour care facility for intravenous fluid therapy for three to five days, as recommended by toxicologists at the ASPCA Animal Poison Control Center. But at this point we could address the dehydration caused by the vomiting and diarrhea with subcutaneous fluids on an outpatient basis. The doctor agreed. He would watch her carefully at home. If her symptoms worsened, we might be looking at life-threatening gastrointestinal damage that could lead to sepsis and anemia. This might require more aggressive treatment such as blood transfusions and injectable antibiotics, but for now she could go home with ten days of medications and follow-up appointments to monitor her progress.

If caught early and treated appropriately, the prognosis for naproxen toxicity in dogs is good. Sandi made a complete recovery. I’m not so sure about the doctor. He wasn’t the first well-intentioned pet owner to inadvertently cause harm to his animal by giving a human medication. He won’t be the last.

The take-home is that things that seem similar are not necessarily interchangeable. Naproxen is not aspirin. Aleve isn’t Bufferin. A dog is not a four-legged human being. A physician is not a veterinarian. Sure, there are plenty of safe and suitable home remedies you can use with your pets, but always check with your veterinarian first.

The Visiting Vet column will not appear on April 19, but will return on May 3.