Xylitol ingestion in dogs

Xylitol is a sugar alcohol used as a sweetener in many products, including sugar-free gum and mints, nicotine gum, chewable vitamins, oral-care products, some peanut butter and various baked goods. It can also be bought in a granulated form for baking and as a sweetener for cereals and beverages. Interestingly, it’s also found naturally in berries, plums, oats and mushrooms.

Posted: 15 December 2018

Xylitol ingestion in dogs

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While xylitol is considered safe in people, dogs can develop serious, life-threatening problems. Its ability to cause hypoglycemia in dogs has been known since the 1980’s, but we now know it can cause other problems such as liver failure and coagulopathy.

Why do we use Xylitol in human food?

  • It has fewer calories
  • It’s as sweet as sucrose
  • It’s a sugar substitute for people on a low-carbohydrate diet
  • It can be used as an energy source for diabetic patients
  • It prevents oral bacteria from producing damaging acids

A big problem from such a low dose

The dose of xylitol that can cause a problem in dogs has been reported as low as 100mg of xylitol per kg bodyweight. It’s important to note that the higher the dose, the more the risk of liver failure.

A very common source of xylitol poisoning comes from sugar-free gum. Some brands of gum contain fairly small amounts of xylitol, whilst others can result in severe hypoglycemia or liver failure with just a few pieces being eaten. How many of us keep packets of chewing gum lying around the car or in the house, waiting to be chewed and swallowed by our inquisitive canine friends?

Problems associated with xylitol

As a sweetener, Xylitol is generally safe in most species, but it's definitely not safe in dogs. We therefore all have a responsibility to let our doggy clients know of the risks.

What happens when a dog eats Xylitol?

The signs can develop rapidly and are often dramatic.

  • Vomiting – this is the most common initial presenting sign
  • Hypoglycemia – a profound hypoglycemia may develop within 30 minutes, but can be delayed for up to 12 hours.
  • Weakness, ranging from lethargy to collapse
  • Incoordination – look for anything from mild ataxia to seizures
  • Coagulopathy and haemorrhage – be on the look out for petechial, ecchymotic and gastrointestinal hemorrhages You may find severely prolonged coagulation times and mild to moderate thrombocytopenia.
  • Liver biochemistry – some dogs develop elevated liver enzyme activity within 12 to 24 hours after xylitol ingestion. Look for elevated alanine transaminase activity, mild to moderate hyperbilirubinaemia and raised alkaline phosphatase levels
  • Hyperphosphataemia – this may be mild or moderate, but is usually a poor prognostic indicator.
  • Hypokalaemia – this occurs from insulin moving potassium into the cells

How to approach a case of canine Xylitol poisoning

Try to work out the amount of xylitol that has been eaten. Some food products will tell you on the packaging, but sadly many don’t give you enough information. For example, in some chewing gums there is as much as 1g of xylitol per piece of chewing gum, so just 1 or 2 pieces of gum can be enough to cause hypoglycaemia in a 10kg dog. As a guide;

  • >0.1 g/kg of xylitol should be considered at risk for developing hypoglycemia
  • >0.5 g/kg may be hepatotoxic

If you think one of your patients may have eaten xylitol, you could recommend;

  • Emesis – this should only be attempted if the animal is asymptomatic
  • Hospitalisation – this will allow you to place the animal on intravenous fluids and monitor blood parameters
  • Blood tests - obtain baseline glucose, potassium, phosphorus, and total bilirubin concentrations. Check liver enzymes
  • Monitoring bloods - glucose concentrations should be checked every couple of hours for the first day
  • Intravenous glucose - give 1-2 ml/kg bolus of 25% dextrose intravenously followed by intravenous fluids containing 2.5% to 5% dextrose to maintain normal glucose concentrations
  • Potassium – if there is evidence of hypokalaemia, consider adding potassium to the intravenous fluids
  • Activated charcoal – this may help, but is unlikely to be beneficial if the sugar has already been absorbed

What is the prognosis?

Cases of uncomplicated hypoglycemia usually have a good prognosis, especially if they receive prompt treatment and support. Cases with mild elevated liver enzyme usually resolve within a few days. Those animals with severely elevation liver enzymes, hyperbilirubinaemia and coagulopathy have a much more guarded prognosis. Any dog that has gone on to develop hyperphosphataemia will carry a poorer outlook.

Are other sweeteners safe?

The good news is that other sweeteners, such as sorbitol and mannitol, have little to no effect on blood glucose concentrations or insulin secretion in dogs. Saccharin, aspartame and sucralose are generally regarded as safe in dogs. You may at most notice some diarrhoea from over-ingestion.

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