Low Blood Sugar (Hypoglycemia) in diabetic dogs and cats

Low Blood Sugar (Hypoglycemia) in diabetic dogs and cats

Hypoglycemia, or low blood sugar, is one of the most common complications that can arise in dogs and cats who have diabetes. Because hypoglycemic episodes can become life-threatening, it is important to be able to notice the relevant symptoms, and to immediately take appropriate action. 

Below are some signs that may point to hypoglycemia:

  • Lethargy
  • Loss of coordination or weakness in gait
  • Behavioral changes, such as restlessness
  • Hunger
  • Muscle twitching/trembling
  • Seizures
  • Vomiting
  • Anorexia (loss of appetite)
  • Blurred vision
  • Unconsciousness

There are several reasons hypoglycemia can occur. One cause is an overdose of insulin, whether it be by mistake or due to changes in the animal’s need for insulin. It is thought that cats are especially prone to hypoglycemia because their likeliness to undergo diabetic remission within the first few months of starting appropriate insulin therapy and implementing high-protein, low-carb diet changes.

Not eating enough or missing a mealtime may also explain hypoglycemia. Other reasons may include excessive exercise, stress, or oral administration of certain non-insulin therapeutic agents, such as sulfonylureas (ie. glipizide).

All hypoglycemic episodes should be treated as medical emergencies because of the potential harm that can be done to the animals if left untreated. In the case where the animal is alert but experiencing clinical signs of hypoglycemia, they can be fed a meal or hand-fed corn-syrup or honey until symptoms improve. If, however, the animal is not alert enough or is in a seizure, a spoon of corn syrup or honey can be taken and rubbed on their gums. When they regain their consciousness, a meal can be given.

It is important that veterinarians be notified of such symptoms. Should the animal be taken for an examination by the vet, intravenous sugar solutions may be injected to restore blood glucose levels. If hypoglycemia was not triggered by inaccurate administration of insulin or a missed meal, veterinarians may re-evaluate the need for insulin as a long-term modification. Changes in diet or exercise patterns may also be discussed.

Tips to prevent hypoglycemia
Although mild hypoglycemia often has no lasting effect, recurrent and persistent hypoglycemia can lead to irreversible harm. In worst cases, the animal may end up in coma or death. Therefore, it is best for owners to take preventative measures to avoid hypoglycemia. Here are some tips:

  • Giving meals at regular, appointed times
  • Giving meals high in protein and low in carbohydrates
  • Avoiding exercise that is more strenuous than usual
  • Regularly monitoring blood glucose level – checking that blood glucose does not drop below 80 mg/dL (4.4 mmol/L)
    • Although it can be tempting to increase insulin upon a high blood glucose reading, this may be dangerous to do so at the owner’s sole discretion. Adjustments should be discussed with the vet.
    • On the other hand, owners are advised to take action following a single low blood glucose reading by lowering or skipping insulin. Still, the vet should be involved in the decision.
    • Blood glucose curves are useful in detecting hypoglycemia that is not yet clinically noticeable.

Controlled diabetes involves not only the absence of the clinical symptoms of diabetes mellitus, but also the absence of hypoglycemia. It is important that owners and veterinarians work closely together to ensure healthy progression for diabetic pets.


- Spector, D. (2013). Preventing and handling diabetic emergencies. Retrieved from website: http://www.vetstreet.com/our-pet-experts/preventing-and-handling-diabetic-emergencies
- Behrend, E., Holford, A., Lathan, P., Rucinsky, R., Schulman, R. (2018). 2018 AAHA diabetes management guidelines for dogs and cats. Journal of American Animal Hospital Association, 46(3), 215-224. Retrieved from website: https://www.aaha.org/globalassets/02-guidelines/diabetes/diabetes-guidelines_final.pdf
- Fernandez, N. J., Barton, J., & Spotswood, T. (2009). Hypoglycemia in a dog. The Canadian veterinary journal = La revue veterinaire canadienne, 50(4), 423–426.



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