Visiting Vet: Little dog brings big challenge

Xylitol, a common sugar substitute found in some medications, may prove fatal to dogs.

Tidbit is a tiny toy poodle, weighing only 5 pounds. OK, I don’t really have a patient named Tidbit, but let’s imagine I do. Little dogs pose unique challenges for veterinarians. It can be easier to wrestle an uncooperative Labrador than to safely handle an annoyed Chihuahua.

What tiny dogs lack in size, they frequently make up for with attitude. But we love their big spirits, and do our best to provide them optimum care. So my imaginary patient Tidbit has had a bad back for years, but now the pain medications we had been using were no longer doing the trick. Tidbit needed something to give her relief.

“Maybe we should try gabapentin,” I suggested. This drug is used in humans to treat epilepsy, restless leg syndrome, and as a pain medication for conditions like diabetic neuropathy. It is also used “off-label” for problems like anxiety, insomnia, and bipolar disorder. In recent years, veterinarians have begun trying gabapentin for pets. In dogs, it seems to be helpful treating chronic nerve-related pain, such as Tidbit was experiencing with her intervertebral disc disease.

The veterinary pharmaceutical industry produces many medications that are formulated and approved specifically for use in animals. Because these companies know our patients can range in size from 2 pounds to 2,000 pounds, they typically market a wide variety of strengths to accommodate this. But veterinarians also utilize pharmaceuticals manufactured only for people. Gabapentin is such a medication. If I wanted Tidbit to try it, I would need to prescribe the human product from a local pharmacy. “Let me figure out her dose,” I said, grabbing my calculator. But for the teeny dose needed for this teeny dog, the tablets made for people were way too big, even if we broke them into quarters.

In such situations, veterinarians may use compounding pharmacies to prepare appropriately downsized doses for little patients. Other times, we may find that certain medications are already available commercially in liquid form, designed for children or people who have difficulty swallowing pills. These liquid formulations make accurate delivery of very small doses easier.

“Oh, look!” I exclaimed as I read through my drug formulary. “Gabapentin comes in a liquid. We could use that for Tidbit … oh … wait … no, we can’t.” Why not? Because the liquid product for people is sweetened with xylitol, and even in small doses, xylitol can be lethal to little dogs.

Xylitol is a naturally occurring substance found in plants such as berries, lettuce, and mushrooms. During World War II, a shortage of regular sugar led to the commercial production of xylitol, which could be manufactured from xylan, extracted from wood. A white crystalline substance, xylitol looks and tastes like sugar. Its use as a sweetener has become increasingly popular in recent years, not just because it has less calories than regular sugar, but because of its reputed beneficial properties. Chewing xylitol gum avoids sugar-related tooth decay, and also has antibacterial action that actually reduces periodontal disease, and may prevent ear and throat infections in children. There are even claims xylitol may reduce the risk of osteoporosis, endometriosis, uterine fibroids, and breast cancer. An occasional sensitive individual may get mild diarrhea from xylitol, but in general it appears to be safe for people. It is now found in all kinds of products, including sugar-free gum and mints, toothpaste, mouthwash, and even cakes and candy.

So why is xylitol dangerous for Tidbit? When people consume xylitol, the sweetener is absorbed very slowly into the body without inducing a significant release of insulin. But Tidbit’s body reacts differently. It absorbs the xylitol extremely quickly, and confuses her tiny canine pancreas. “Here comes a huge sugar rush,” her pancreas thinks. “I better pump out a big blast of insulin fast!” But her body doesn’t really need that big insulin surge. Xylitol is not real sugar. The insulin surge makes Tidbit’s blood sugar plummet. This profound drop in blood sugar is life-threatening. The first sign is usually vomiting, followed by lethargy, weakness, collapse, seizures, and sometimes, death. Onset of symptoms is rapid — as little as half an hour after ingestion — but occasionally may be delayed as long as 12 hours. Effects may persist for a day or more. In a small dog, ingestion of just two pieces of gum can be fatal.

Not every sugar-free product uses xylitol. Aspartame, saccharin, sucralose, and stevia are other common artificial sweeteners, and these do not cause hypoglycemia in dogs. But more and more products are now using xylitol. Some of the common xylitol-containing products you might have in your house include Trident gum, Icebreaker mints, Tom’s of Maine Toothpaste, and TicTacs. Some over-the-counter medications that used to be safe to use in dogs have been reformulated to be sweetened with xylitol. Even a kind of peanut butter spread sold by GNC, called Nuts ‘n More, contains xylitol.

So what should you do if Tidbit eats the Trident? As with any poisoning, first grab the package, as that will help your veterinarian determine the degree of exposure. Then call your veterinarian, pronto. If ingestion was recent, we can try to get it out of her system by inducing vomiting. If, however, the xylitol has already reached the bloodstream, it is too late for making her throw up. Instead, we must monitor her blood sugar levels. If they are too low, it may be necessary to give intravenous fluids containing dextrose for 24 hours, or even longer. Once treatment is instituted, the prognosis is excellent, though in certain cases dogs may develop liver failure up to a week later. Symptoms of liver failure include vomiting, lethargy, bruising, and gastrointestinal hemorrhage, and it is often fatal.

The take-home message is simple. Read labels. Carefully. If xylitol is in the ingredient list, don’t give it to your pet. For my imaginary patient Tidbit, I’m calling the imaginary compounding pharmacy and having it mix up a batch of imaginary liver-flavored gabapentin, sans xylitol, which I hope will relieve her imaginary back pain.