Just Ask the Expert: Your insulin options in diabetic dogs

Jul 01, 2013

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Q. With so many insulin products to choose from, how do I decide which insulin is the best for my canine patients?

Dr. David S. Bruyette
A. Because there are several insulins to choose from, selecting an insulin for a newly diagnosed diabetic dog can be confusing. And how do you decide what to switch to in a dog that is responding poorly to a particular insulin? Here are my thoughts on where you might turn.

Vetsulin (Merck Animal Health)

Vetsulin has recently been reintroduced to the veterinary market and is approved for use in both dogs and cats. This is the same product that was previously available from Intervet/Schering-Plough Animal Health.

This porcine-origin zinc Lente insulin is classified as an intermediate-acting insulin. Canine and porcine insulin have an identical amino acid sequence, which eliminates the theoretical complication of a dog's developing anti-insulin antibodies that may adversely affect glycemic control.

One important change that occurred with the relaunch of Vetsulin is the manufacturer's recommendations regarding handling of the insulin. Vetsulin should be shaken thoroughly until a homogeneous, uniformly milky suspension is obtained. This is a markedly different way of handling insulin, so be sure to read the package insert for further handling instructions.

This insulin is available only at a concentration of 40 IU/ml, so make sure you provide U-40 insulin syringes to owners. Reassess the dog's clinical signs and perform a serial blood glucose curve one week after starting therapy.

While the manufacturer's package insert recommends once-a-day initial dosing, I have not found this to be effective in most of our patients. I suggest an initial starting dose of 0.5 U/kg given subcutaneously twice a day.

With the return of this product to the market, it will be my preferred insulin for the initial management of diabetes in dogs.

Humulin N

This intermediate-acting, human recombinant insulin is not approved for use in dogs, but it is safe and efficacious for controlling blood glucose concentrations in dogs.

The results of a recent study evaluating Humulin N's efficacy in 10 client-owned dogs showed that it effectively controls diabetes mellitus when given subcutaneously twice a day but that postprandial hyperglycemia can occur in some well-regulated dogs.1

The suggested starting dose is 0.5 U/kg given subcutaneously twice a day. Reassess the dog's clinical signs and perform a serial blood glucose curve one week after starting therapy.