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Bark n Wag 15 Minute Vet Talk

Nov 12, 2023

Managing canine diabetes

Giving your dog a long, happy life

Learning your dog has diabetes can feel like a punch to your gut. Up to 1% of all dogs may develop diabetes during their lifetime. While this is a serious diagnosis, treatment options and management strategies can give your dog a long, quality life. 

Diabetes mellitus revolves around a lack of insulin or a lack of the body’s response to insulin. Insulin therapy is a mainstay of treatment.

Understanding your dog’s prognosis

As with so many canine health problems, early diagnosis is key to your dog living a full life. Caught early, with treatment started right away and careful monitoring, many dogs with diabetes live full, active lives. The battle will be more difficult with dogs who have these issues: 

  • Phosphate levels
    • Dogs who have high levels of phosphate in their blood at the time of diagnosis tend to have a slightly less positive prognosis. The exact reason for this is unknown, but it emphasizes the need for a complete blood chemistry panel at the time of diagnosis. 
  •  Medical history
    • Dogs who are more than 10-years-old, overweight, have a history of pancreatitis or are battling hyperadrenocorticism (Cushing’s disease) are more likely to have problems. 
    • Dogs with hypothyroidism have a slightly higher risk of becoming diabetic, and any dog who has required treatment with glucocorticoids for long periods of time is also at risk. 
  •  Breeding
    • A study from the United Kingdom suggested that Border Terriers, West Highland White Terriers and Cocker Spaniels had lower survival times than Border Collies. 
    • Tibetan Terriers, Cairn Terriers and Samoyeds are also considered high-risk breeds for diabetes. 
  •  Females 
    • While female dogs have a higher risk of developing diabetes, if they are spayed, they can be managed quite well. 

Starting therapy

After your dog has been definitively diagnosed with diabetes, treatment with insulin will be the starting point. Dogs who are ill may need to be hospitalized and started with rapid-acting insulin injections. Most dogs will be feeling relatively well and can start treatment at home under veterinary guidance. 

Customizing treatment for diabetics is essential. Individual dogs may respond to one type of insulin but not another. Some dogs become resistant to a certain type after time and need to change. Dosages can vary greatly among dogs, as can the timing of dosages. Typically, dogs will start off on insulin injections twice a day, around their feeding times. But be prepared for the experimentation necessary to find the ideal protocol for an individual dog. 

Veterinary staff will explain how to handle and store insulin, and how to correctly use the syringes. Different strengths and types of insulin come in different units, and you need to carefully match the syringes you use with the insulin type. Insulin is sensitive and must be stored carefully, not too cold or too hot. Even shaking it too vigorously can harm this medication. Some insulins need to be rolled rather than shaken. Never use insulin past its expiration date. 

Finally, you will learn how to give the injections. Some clinics have you practice on something like fruit until you are comfortable with doing the injections properly. Injections are given subcutaneously, reaching the fat between the surface skin and muscle below. The needles are a small diameter and very sharp, so most dogs handle the injections well. Needles and syringes need to be disposed of properly. You will need a sharps container and to learn how to dispose of the needles in your town. 

Insulin-glucose response curve

Once you have the basics down, you will help fine-tune your dog’s treatment. Trial and error is used to determine the best insulin, the ideal dose, timing and how to coordinate feedings with the dosing schedule. For the first week or two, while your dog’s body adjusts to the insulin and you get your routine down, your veterinarian may have you monitor your dog via urine glucose strips. These give you a rough idea as to whether your dog is handling the insulin without getting their glucose levels too low.

The ideal method for determining all these factors is to create a glucose response curve. Glucose is one of the main factors influenced by insulin. Tracking results of glucose in the blood is an easy way to know if your insulin dose is correct. Urine glucose monitoring can also help but is not as precise. 

To create a glucose curve, blood glucose levels are checked about every two hours over a 12-hour period, if possible. That many blood tests can be expensive, but it is worth it to get your dog on the right track. Using the glucose curve, your veterinarian will see when the insulin starts to act, how long a single dose provides treatment, when the insulin is at its highest level of activity and when it fades out. While running the glucose curve, your dog’s feeding (timing and portions) are carefully controlled. Based on the highs and lows of the curve, adjustments may be made in dose, timing of meals and amount fed. 

Normal blood glucose levels in healthy dogs are 80-120 milligrams per decilitre (mg/dl). Most dogs can handle levels going as high as 250 with minimal side effects. Post mealtimes, some dogs may normally go up to 400 but that is a temporary effect. Once blood glucose levels go over 200, glucose will be detectable in the urine. 

Factors influencing insulin dosing

Because glucose is a basic nutrient, many factors can affect a dog’s requirements. Obese dogs need to lose weight, so that should be factored in. If your dog has a successful weight-loss program, insulin amounts will decrease. Activity levels also require different amounts of insulin. A dog who is running agility trials will end up with a different dose than a dog who strolls sedately around the block once or twice a day. Female dogs who go into heat will often have different insulin needs than a spayed dog ( — it is generally recommended to spay an intact diabetic female to even out insulin requirements).

If your dog is sick or becomes hypothyroid (low thyroid hormone production), their insulin needs will change. If your dog skips their morning meal and doesn’t eat, you need to contact your veterinarian to discuss adjustments in the insulin dose. Insulin needs the “raw material” of the food to be effective. 

Monitoring your diabetic do

If your dog is not showing any clinical signs of hyperglycemia (high blood sugar or glucose levels), such as drinking more than usual, being extra hungry or urinating excessively, then your dosing should be in the right ballpark. Even so, periodic blood testing is recommended. 

Having hypoglycemia (low blood sugar or glucose levels) is more serious. If your dog is very lethargic, sleeping more than usual and resisting activity, then they may have hypoglycemia. Some of these dogs will have tremors, difficulty walking and can collapse into a coma. 

The brain is very dependent on glucose for its nutrition, so any changes in mental state could mean hypoglycemia. If you suspect this, you can put corn syrup or honey on your dog's gums. If they are alert, a meal of cooked pasta with some syrup or honey can help to quickly raise their blood sugar. The response should be fairly rapid. Contact your veterinarian if you suspect that your dog has high or low glucose levels.

Fairly new on the scene are continuous or flash glucose-monitoring systems. These high-tech systems use an electrode inserted in the subcutaneous tissues of your dog. They give off a small current determined by the amount of glucose in the interstitial tissues. That charge is then converted to a glucose amount and displayed on a monitor. 

Two systems have been used successfully in veterinary medicine: the MiniMed iPro2, a continuous monitoring system, and the Abbott Freestyle Libre, which is a flash system. These systems can provide a picture of your dog’s daily blood glucose levels while they are at home and doing normal activities. 

Best management practices

The goal with your diabetic dog is to mimic a healthy dog’s glucose status.

You want a normal rhythm with no clinical signs of too high or too low. That means a steady routine, ideally feeding your dog the same diet, at the same time every day. Plan your dog’s activity for each day. If you have an unusually active day planned, ask your veterinarian ahead of time about any recommended adjustments in insulin or food.

A steady state minimizes long-term damage from diabetes to organ systems like the heart, liver and kidneys. Even dogs who are well-managed may eventually develop cataracts, but it takes longer in dogs who have relatively well-controlled glucose levels. 

Once your dog is on a set schedule, costs and complications are minimal. 

Side effect cataracts

Cataracts are a common side effect of canine diabetes. These cataracts tend to mature quickly and may be associated with inflammation. A veterinary ophthalmologist can evaluate your dog’s eyes to determine if cataract removal would improve vision. 

If the ophthalmologist recommends removal, a well-regulated diabetic dog can have general anesthesia and surgery to remove the damaged lens. An artificial lens may be put in place at that time. If your dog is not a surgical candidate, don’t despair. Blind dogs usually adjust well to their loss of vision. 


With careful monitoring, many dogs with diabetes live full, active lives. It is important for owners of diabetic dogs to keep a notebook charting daily dosage, diet, and activity. Doing so can alert you to any developing problems. 

This article has been reprinted with permission from the Cornell University College of Veterinary Medicine’s DogWatch newsletter, published by Belvoir Media Group.