By Dr. Becker
Xylitol is a natural sugar alcohol extracted from certain fruits and vegetables. Because of its sweet taste and plaque fighting benefits in humans, xylitol is a common sugar substitute found in a diverse assortment of products. These include sugar-free gum, mints and other candy, baked goods, nicotine gum, chewable vitamins, certain prescription drugs, and dental hygiene products. Nontoxic amounts are even included in some pet dental products.
Because xylitol has a low glycemic index, it's also sold in bulk as a sugar substitute for baking and in-home use -- which is why the Pet Poison Helpline has fielded calls from owners of dogs that became very sick after eating homemade bread, muffins and cupcakes made with xylitol.
Where Else Is Xylitol Found?
According to the Pet Poison Helpline (PPH), xylitol – which as many pet owners know is quite toxic for dogs, causing hypoglycemia and hepatic necrosis – is showing up in an ever-increasing number of surprising places. New products on the market, including some nasal sprays, over-the-counter sleep aids, multivitamins, prescription sedatives, antacids, stool softeners, and smoking-cessation gums, contain "unexpectedly large amounts" of xylitol, according to Dr. Anna Brutlag of PPH.
Dogs who sample these products get a double dose of toxicity, first from the active ingredient in the product, and secondarily from the xylitol. This potentially deadly combination can greatly complicate the symptoms, diagnosis, treatment, and prognosis for these animals.
According to Dr. Brutlag, the following "atypical" products contain xylitol. Some may surprise you…
- Axia3 ProDigestive Antacid (flavored chewable tablets, propriety amount)
- Children's Allegra Oral Suspension
- Fleet Pedia-Lax Liquid Stool Softener
- Umcka Cold and Flu chewable tablets (homeopathic product)
Dietary supplements, vitamins:
- KAL Colostrum Chewable, Vanilla Cream (chewable tablets)
- KAL Dinosaurs Children's Vitamins and Minerals (chewable tablets)
- Kidz Digest Chewable Berry from Transformation Enzyme
- L'il Critters Fiber Gummy Bears
- Mega D3 Dots with 5,000 IU of Vitamin D3 per "dot" (dissolvable tablet)
- Stress Relax's Suntheanine L-Theanine chewable tablets
- Vitamin Code Kids by Garden of Life (chewable multivitamins)
- Super Sleep Soft Melts by Webber Natural (dissolvable tablets)
- Xlear Sinus Care Spray
- Xylear Nasal Spray (for adults and children)
- Xyliseptic Nasal Spray
- Abilify Discmelt Orally Disintegrating Tablets (aripiprazole)
- Clonazepam Orally Disintegrating Tablets, benzodiazepine
- Emtriva oral solution (emtricitabine), HIV-1 reverse transcriptase inhibitor
- Mobic Oral Suspension (meloxicam), nonsteroidal anti-inflammatory
- Neurontin (gabapentin) Oral Solution
- Riomet (metformin) Oral Solution, antidiabetic agent
- Varibar barium sulfate products, liquids and puddings for swallowing studies
- Zegerid Powder for Oral Suspension (omeprazole), proton pump inhibitor
Foods with xylitol as the primary sweetener (excluding gums and mints):
- Clemmy's Rich and Creamy ice cream products
- Dr. John's products (hard and soft candies, chocolates, drink mixes and so on)
- Jell-O sugar-free pudding snacks
- Nature's Hollow jams, syrup, ketchup, honey and so on
- SparX Candy
- Zipfizz energy drink-mix powders
Toxicity of Xylitol Is Species- and Dose-Dependent
While xylitol is safe for human consumption, the same can't be said for pets. In 2011, the FDA released a consumer alert on the dangers of xylitol ingestion in certain animals. The sweetener's effect varies by species. In people, rhesus monkeys, rats, and horses, intravenous (IV) xylitol causes little to no insulin release. However, it has the opposite effect on baboons, cows, goats, rabbits, dogs, and ferrets. Its effect on cats is unknown.
Humans absorb xylitol slowly, and the sweetener when ingested orally is absorbed at from about 50 to 95 percent. However, in dogs, xylitol is rapidly and completely absorbed within about 30 minutes. Just a small amount of xylitol can cause a dangerous insulin surge and a rapid drop in blood sugar.
The toxicity of xylitol in dogs is dose-dependent. The dose required to trigger hypoglycemia (low blood glucose) is approximately 0.1 grams/kg, while the amount needed to cause hepatic necrosis (liver failure) is approximately 0.5 grams/kg. As a point of reference, most chewing gums and breath mints typically contain .22 to 1.0 gram of xylitol per piece of gum or per mint. This means just a single piece of gum or one mint may cause hypoglycemia in a 10-pound dog.
Determining the Amount of Xylitol in a Product
Product manufacturers aren't required to list the quantity of xylitol on package labels, and while some companies will reveal the amount in their products, many are reluctant to do so. Incredibly, some have even asked veterinarians to sign a confidentiality agreement before divulging how much of the sweetener is in a particular product.
Fortunately, the Pet Poison Helpline has been working to get this information from manufacturers, and has been relatively successful. So if you need to know the amount of xylitol contained in a specific product, the Helpline suggests you call them first at 1-800-213-6680.
In some cases, you might be able to use the placement of xylitol on an ingredient list to estimate how much is in the product. In the U.S., ingredient lists for foods must be organized in descending order based on weight. The ingredient that weighs the most is at the top of the list. According to Dr. Brutlag, in most chewing gum ingredient lists, xylitol appears in fourth or fifth place, making it clinically insignificant. She says if it appears as one of the first three ingredients, however, extreme caution should be taken.
I'll go a step further and recommend that dog guardians avoid or very carefully secure any product that contains any amount of xylitol, no matter how small.
When it comes to medications and dietary supplements, U.S. regulations do not require manufacturers to list xylitol by name on package labels. This is because the sweetener is often categorized as an "inactive" or "other" ingredient, and such ingredients don't have to be listed in order by the amount contained in the product. To confuse matters further, when xylitol is named in these products, it is often part of an alphabetized list, which could lead pet owners to assume – perhaps in error – that there is a very small amount in the product.
So I'll repeat my recommendation to dog owners to either avoid or very carefully store any product that contains xylitol in any amount.
Symptoms of Xylitol Poisoning and Required Treatment
Symptoms of xylitol intoxication in dogs include vomiting, weakness, lethargy, loss of coordination, seizures, and collapse.
Hypoglycemia is usually evident within an hour or two after a dog ingests xylitol, but symptoms are occasionally delayed for several hours. Treatment depends on how quickly it is given. Vomiting is induced in cases where the xylitol has just been ingested. Once a dog develops hypoglycemia, IV dextrose must be administered until the animal can self-regulate his blood glucose concentrations, which typically takes from 12 to 48 hours.
In dogs who ingest enough xylitol to cause liver toxicity, liver enzymes must be closely monitored, as evidence of hepatic necrosis can show up one to two days after ingestion. Should the liver begin to fail, the dog will require IV fluids, dextrose, hepatoprotectants (substances to help support and repair the liver), and regular monitoring of blood clotting activity.
When xylitol exposure is caught early in a dog and treated effectively, the prognosis for a full recovery is excellent. The prognosis for dogs that develop hepatic failure is less optimistic.