Renee D. Schmid, DVM
Associate Veterinarian, Clinical Toxicology at Pet Poison Helpline®
Xylitol is a sweetener that is highly toxic to dogs. Rabbits, cows, baboons and horses have also demonstrated sensitivity, although to a lesser extent. There have even been anecdotal reports of sensitivity in cats and ferrets, although there is no published data on these species. Xylitol is a potentially fatal threat to dogs and the risk of exposure seems to increase daily. We often think of sugar free gum and candy when we first hear about xylitol poisoning. However, as xylitol increases in popularity due to the safety and benefits for humans, gum and candy are not the only products to be concerned about. By understanding the benefits and properties of xylitol, you can better predict which products may contain it and, in turn, help predict which of your patients may be at risk for poisoning.
Xylitol is a naturally occurring sugar alcohol that is produced from the bark of hardwoods as well as corncob remnants from ethanol plants. Over the last 40-50 years, xylitol has been proven to be extremely safe in people and recent research has demonstrated increasing health benefits, resulting in wider usage. The benefits of xylitol also extend beyond that of human health, which has led to the inclusion of xylitol in non-food products. While one of the most common uses of xylitol remains as a sugar-substitute, xylitol is also a very effective anti-cariogenic (anti-cavity), humectant (retains moisture) and antimicrobial. With these benefits, many products contain xylitol for more than one reason.
Xylitol has approximately the same sweetness factor as sucrose and a very low glycemic index which makes it ideal for diabetics and others seeking a healthy alternative to sucrose. Xylitol is in many sugar-free products including gum, candy, peanut butter, protein bars and weight loss products. The anti-cariogenic property makes xylitol an ideal ingredient in oral care products such as gum, toothpaste, mouthwash, dental floss and oral rinses. There are even veterinary oral rinses and water additives that contain xylitol. Fortunately, veterinary products use very low concentrations of xylitol and routine use is not expected to cause toxicity concerns. Humectants help to retain moisture, making xylitol an additive seen in lotions, facial products, deodorants and skin gels. Xylitol also has proven antimicrobial properties to oral bacteria as well as bacteria commonly seen with ear infections in children. As such, medications and preventative products for these indications may contain xylitol. Due to the cooling sensation on contact with mucous membranes, xylitol is often added to nasal sprays, throat lozenges, hard candies and gum. Xylitol prevents fermentation and molding from occurring, which makes it an ideal additive to both food and non-food products.
All of the beneficial properties of xylitol make it a common additive in liquid or chewable prescription and nonprescription medications. Any supplement, vitamin, over the counter, compounded or prescription medication should raise a flag for potentially containing xylitol. The ingredient list should be closely examined to determine whether or not xylitol is present. Xylitol will be added to the main ingredient list in food type products, but may be in the inactive ingredients section for medications and supplements. If an owner is calling regarding a compounded medication, they should check with the compounding pharmacy for a list of ingredients, if not supplied with the medication.
One of the most critical steps in managing a potential xylitol poisoning is obtaining an accurate dosage as this will eliminate the risk of under or over treating your patient. Dosages can be difficult to calculate as the xylitol content of gums, candies, food and non-food products vary greatly. Pet Poison Helpline® has a large data base cataloging the specific xylitol content for many products, and the list is growing every day. When in doubt of the xylitol concentration in a given product, please call us for consultation.
Xylitol intoxication is expected with doses as low as 0.1g/kg body weight as this is the point at which hypoglycemia typically occurs. Acute hepatic necrosis may develop with doses of 0.5g/kg and above. Effective treatment for xylitol toxicity that is <0.5g/kg includes emesis, blood glucose monitoring, IV fluids and dextrose supplementation if hypoglycemia develops. Typically, patients should be monitored for 12 hours and if, hypoglycemia occurs, 24-48 hours of therapy may be needed. For ingestions >0.5g/kg, in addition to the previous recommendations, monitoring liver enzymes for 48-72 hours and the initiation of hepatoprotectants should begin. Depending on the severity of the case, n-acetylcysteine may be another helpful addition. If acute hepatic failure occurs, monitoring for the development of a secondary coagulopathy will be needed. Although the prognosis for dogs ingesting >0.5g/kg is guarded, with early intervention and aggressive therapy, many patients survive and return to normal liver function with no residual effects.
For information to share with your clients, please download our pet owner friendly PDF on xylitol.