Feline Diabetes Mellitus

Diabetes mellitus is a hormonal disease that occurs in about 1 out of every 400 cats. It is characterised by elevated blood glucose (blood sugar) levels.  If untreated, it can lead to life-threatening metabolic disturbances. Diabetes in cats is most similar to type II or adult onset diabetes in humans.

The hormone insulin is produced in the pancreas and is responsible for allowing glucose to be taken into cells to provide energy. If there is resistance to this action or there is a reduction in the total amount of insulin produced, then the cat becomes diabetic.

The cats who are most at risk for developing diabetes are cats over eight years old, male cats, Burmese cats and cats who are overweight.

Signs and Symptoms

Clinical signs of diabetes include:

  • excessive drinking
  • excessive urinating
  • increased appetite
  • problems walking or jumping.  (This is caused by neuropathy which causes poor nervous control to the cat’s hind legs)


Diagnosis involves blood and urine tests to demonstrate high blood glucose and the presence of glucose in the urine. Sometimes a test for fructosamine is required to distinguish between cats which are stressed and those that are truly diabetic.


Diabetes is a very treatable disease, but requires long term commitment. Treatment options include:

  • treating underlying disease (if there is one)
  • insulin therapy (the preferred method, and the one that provides the best control of blood sugar)
  • dietary management  (there have been significant advances in dietary treatment of feline diabetes recently)

After your cat has been diagnosed with diabetes, the next step is to determine the correct type and dose of insulin for her. This varies from cat to cat, and your cat will probably have to spend several days in the hospital.  She will have her blood glucose measured every few hours as the vet determines the correct treatment for her.

Your cat will need to return to the vet:

  • Every week for 3 weeks and then
  • Every month until a stable dose is determined.
  • From then on cats usually return to the clinic every 3 months for a check up.

Insulin Instructions

  • Insulin must be stored in the refrigerator.
  • If your cat is on a crystalline insulin it must be gently mixed by rolling for 30 seconds prior to each use.
  • Glargine (Lantus) insulin does not need to be mixed.
  • A new syringe should ideally be used for each injection.
  • Injections can be given under the skin anywhere on the body but the "scruff" is often easiest and less painful.

Your cat must be monitored closely while he is on insulin therapy.

DO NOT change the dose without consulting your veterinarian. If your cat gets too much insulin it can cause blood glucose levels to become dangerously low.  Your cat could become weak, lethargic or unsteady on her feet.  She could go blind, go into a coma or die.

If your cat accidentally gets too much insulin or if it shows any of these signs, take her to the vet immediately. You might try rubbing honey or glucose syrup on her gums as an emergency treatment.


Approximately 50% of cats diagnosed with diabetes and treated appropriately will go into remission and no longer require insulin injections. Early diagnosis and aggressive treatment with long-acting insulin and a low carbohydrate diet will increase the chance of your cat going into remission.