Visiting Veterinarian : Xylitol: Not for dogs
By Michelle Gerhard Jasny V.M.D.
Published: September 24, 2009
Nowadays most pet owners know chocolate isn't good for dogs. In fact, people often panic unnecessarily over the slightest exposure. It's not cyanide, folks. If your 100-pound mastiff eats an M&M, there's no cause for alarm.
At least half the frantic calls I get about chocolate ingestion involve doses well below the levels to cause any concern. The risk does increase, however, if the chocolate is semisweet or bittersweet, if the amount consumed is large, and if the dog small. It always makes sense to check with your vet. We can do the math, and if necessary, the medicine should your chocoholic pooch overindulge.
But there is another danger lurking in your pantry. A substance far more toxic to dogs than chocolate: gum. That's right, gum. Not all gum, but many brands of sugar-free gum, as well as any other products that contain the sweetener xylitol.
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 fewer calories than regular sugar, but because of its reputed beneficial properties.
Chewing xylitol gum avoids sugar-related tooth decay but 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. It can be found in toothpaste, mouthwash, gum, mints, cakes, candy, and many other foods.
So why can you feed it to your children but not your Chihuahua? When human beings consume xylitol, the sweetener is absorbed very slowly into the body without provoking any significant release of insulin. When Tic-Tac, the terrier, tears into the Trident, it's a different story. Tic-Tac absorbs xylitol extremely quickly, and then his little canine pancreas gets confused. "Whoa, here comes a huge sugar rush," his pancreas thinks. "I better pump out a big blast of insulin fast!"
But there's a problem. That big insulin surge isn't really needed. Xylitol is not the same as sugar (i.e., glucose). The insulin grabs up all the glucose and his blood sugar plummets. The result is a profound, life-threatening hypoglycemia a la Sonny Von Bulow. The first sign is usually vomiting, followed by lethargy, weakness, collapse, seizures, and, sometimes, death.
Onset of symptoms is usually rapid - as little as half an hour after ingestion - but may be delayed as long as 12 hours. Effects may persist for a day or more. The scariest part is how little xylitol it takes to cause a big problem. In a small dog, ingestion of two pieces of gum can cause a potentially fatal drop in blood sugar.
Before you overreact and throw away every sugar-free product in your cupboard, let's clarify. We're not talking about aspartame, saccharin, sucralose, or stevia. We're not talking about Splenda or Equal.
Read labels. Some products, like Trident gum, clearly mark that the product contains xylitol. Other products make it harder to find the information. Read the fine print. Some labels lump xylitol along with sorbitol, isomalt, maltitol, and mannitol under the heading "sugar alcohols." Only xylitol is toxic to dogs.
So what should you do if Tic-Tac eats the Tic-Tacs? As with any poisoning, first grab the package, if you can readily lay your hands on it. This will help us determine the degree of exposure. (Tic-Tac breath mints are one of the most frequent culprits, due to the high concentration of xylitol in each mint, and the popularity of the item.)
Then call your veterinarian, pronto. If Tic-Tac is already showing signs of hypoglycemia, it is too late to make him throw up. The xylitol has already reached his blood stream. The insulin surge has occurred. Inducing vomiting may only make things worse. If, however, you catch him in the act, there may still be time to get the stuff out of his system.
Your veterinarian can induce vomiting at the office or instruct you on methods to do this at home before you head for the clinic. Feeding a few slices of whole grain bread first may slow the absorption of the xylitol and make it easier for Tic-Tac to barf up the offending item.
Next, we begin monitoring his sugar and, if necessary, start an intravenous drip containing dextrose for 12 to 24 hours, occasionally even longer. (On the Vineyard, that may mean a trip off-Island to an emergency clinic with a 24-hour ICU after your local vet here has done the initial stabilization.)
Once treatment is instituted, the prognosis is excellent. A second type of xylitol toxicity has been identified in the last few years in which certain dogs develop acute liver failure and clotting disorders up to 72 hours after ingestion. Sadly, when xylitol-related liver failure occurs, the mortality rate is high. Many of these cases have no preceding signs of hypoglycemia. Symptoms include vomiting, lethargy, bruising, and gastrointestinal hemorrhage. The reason some dogs have this reaction and others do not may be dose-related but no one knows for sure.
Over the last few years, veterinarians have been trying to spread the word about this little-known problem. We want dog owners to be as informed and concerned about xylitol as they are about chocolate. So read those labels. Give Tic-Tac a nice rawhide bone to chew, but eschew the sugarless gum.
