Vetsulin® (porcine insulin zinc suspension) is a sterile, aqueous suspension of purified porcine insulin. Vetsulin contains 40 IU per mL, consisting of 35% amorphous and 65% crystalline zinc insulin. Vetsulin is a lente, or intermediate-acting, insulin.
Unlike human insulin, porcine insulin has the same amino acid sequence as canine insulin, making it less likely for dogs to develop anti-insulin antibodies.
In dogs, the amorphous fraction will reach its maximum effect approximately 4 hours following subcutaneous administration, and its effects last for about 8 hours thereafter. The effect is maintained by the crystalline fraction, which has a slower onset of action and peak effects around 11 hours following injection. The duration of activity of Vetsulin generally ranges from 14–24 hours in dogs.
In cats, the peak activity following subcutaneous administration of Vetsulin occurs between 1.5 and 8 hours (with an average of about 4 hours1), and the duration of activity varies between 8 and 12 hours.