How to Inject a Dog With Insulin

In dogs, insulin therapy is often started with NPH or Lente human insulin. These dogs are fed two equal meals each day. An insulin injection is given at each mealtime.

The veterinarian may adjust your dog’s insulin dose by a small amount every few weeks, until the dog appears to be well regulated. These adjustments are based on the dog’s body weight and clinical signs of diabetes such as thirst and urination.

To help fine-tune your dog's insulin therapy, the veterinarian may test the dog's urine glucose, fasting blood glucose, fructosamine, glycosylated hemoglobin (same as A1c test in people) or create a blood glucose curve. In your dog's case, some of these tests may not be necessary.

It is important to monitor the dog for a few weeks after a change of insulin dose. This is because the dog’s body needs a few weeks to adjust to the new insulin level. You cannot tell if an insulin adjustment is working until after several weeks have passed and the dog's hormones have settled down. Try to be patient and allow your pet to adjust to lowered blood glucose levels.

Insulin Injection Tips

  • Spend as much training time as you need with the veterinarian to make sure that you understand how and when to give your dog insulin. For a refresher, look at our photo tutorial: how to inject your dog with insulin.

  • It is not necessary or desirable for you to try keeping your dog's blood glucose at "normal" levels of 80-120 mg/dL. This puts your pet at risk of hypoglycemia (very low blood glucose).

  • Diabetic dogs can experience large day-to-day fluctuations in blood glucose levels, even if their food and insulin are kept constant. This is why it may take several months for the veterinarian to fine-tune your dog's insulin doses.1

  • It is best to inject insulin immediately after the dog has eaten. If the dog ate only some of its food, vomited or did not eat at all, your veterinarian may suggest that you decrease the insulin dose by half. Never skip the insulin dose entirely, but follow your veterinarian's advice. If your pet does not eat for two meals in a row, call your veterinarian before injecting insulin.

  • If you inject your dog twice a day, try to give the insulin at the same general time each day, such as breakfast and dinner. However, if these times vary occasionally by 30 to 60 minutes, it will probably not matter. Your pet will probably be fine.

  • If you are not sure whether an insulin injection should be given, call your veterinarian for advice.

  • Cold insulin hurts. Do not take insulin from the refrigerator and inject it immediately into your pet. Let the insulin come to room temperature. This may take around one hour.

  • Always praise your dog or give it a treat after injecting it, so that it associates the insulin therapy with a pleasant experience.

  • Although Vetsulin® pork insulin is approved for once a day dosing, veterinarians generally do not favor once a day insulin therapy because it is hard to regulate a dog with only one daily injection. Once a day insulin therapy is used only when the owner is not able to give the dog two injections a day, or in those cases where a dog can be well regulated with one daily injection. Your veterinarian can recommend a proper dosing regimen for your dog.

  • Unopened vials of insulin should be stored in the refrigerator. Write the date of opening on the vial label as a reminder to discard the vial after one month of use.

1.  Evaluation of day-to-day variability of serial blood glucose concentration curves in diabetic dogs. Linda M. Fleeman, BVSc, and Jacquie S. Rand, BVSc, DVSc, DACVIM




The BD Diabetes Learning Center describes the causes of diabetes, its symptoms, and diabetes complications such as retinopathy and neuropathy. This site contains detailed information about blood glucose monitoring, insulin injection and safe sharps disposal. Interactive quizzes, educational literature downloads and animated demonstrations help to teach diabetes care skills.

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