Managing Diabetic Cats

Insulin therapy for the treatment of feline diabetes

Exogenous insulin is used to replace the inadequate or absent supply of insulin in diabetics.


Insulin preparations can be divided into three categories.

  1. Long-acting insulins
    • Ultralente insulins - 100% crystalline insulin
    • PZI insulins - contain protamine and zinc
  2. Intermediate-acting insulins
    • Lente insulins (e.g. Caninsulin) - mixtures of 30% amorphous (semilente) and 70% crystalline (ultralente) insulin in an aqueous suspension.
    • NPH insulins - contain protamine
  3. Rapid-acting insulins
    • soluble insulin and semilente insulin
    • intravenous administration possible

Due to differences in metabolism, the duration of activity of any particular insulin will vary from animal to animal.

The source of the insulin can vary. Caninsulin contains porcine insulin. Porcine insulin differs from feline insulin in respect of one key amino acid.

Insulin preparations

  • 40 IU = 40 units per ml (Caninsulin)
  • 100 IU = 100 units per ml (others)

40 IU insulin offers the advantage of accurate dosing of small doses of insulin.  Research has shown that, with a 100 IU insulin, it is not possible to deliver a dose of 2 IU (or less) accurately using available syringes.

It is important to match the insulin preparation with the correct syringe or insulin pen. Merck Animal Health provides 40 IU syringes and VetPenĀ® to allow the accurate measurement of Caninsulin doses.

Managing diabetic cats