Vetsulin has been used to manage diabetes in our dogs and cats for years. Recently, batches of the crystalline zinc insulin may have made its way into the vetsulin batch. This may affect the duration of activity or have fluctuations in the glucose level. If your pet is receiving vetsulin to control his diabetes, you will need to contact your veterinarian.Vetsulin will probably not be available next time you refill and you and your veterinarian will have to transition your pet to a different insulin product and dosage. When giving your pet insulin, be sure to shake the bottle well before drawing up your dose and be watchful of the expiration date.  The alert from FDA’s Center for Veterinary Medicine Alerts is listed below.

The Food and Drug Administration’s (FDA) Center for Veterinary Medicine (CVM) and Intervet/Schering-Plough Animal Health are alerting veterinarians and pet owners that Vetsulin®, a porcine insulin zinc suspension used to treat diabetes in animals, may have varying amounts of crystalline zinc insulin in the formulation. Because this Intervet/Schering-Plough Animal Health product is out of specification it could cause a delay in insulin action and an overall longer duration of insulin activity. Products having significant problems with stability can affect the management of chronic diseases. Unstable insulin products can result in unpredictable fluctuations in the glucose levels of diabetic patients. Intervet/Schering-Plough Animal Health is unable to assure FDA that each batch of their product is stable.

FDA and Intervet/Schering-Plough Animal Health request that veterinarians closely monitor their patients receiving Vetsulin® for any changes in onset or duration of activity, or for any signs of hyperglycemia or hypoglycemia. The classic signs of hyperglycemia include increased thirst, increased urination, weight loss and lethargy. The classic signs of hypoglycemia would include disorientation, unsteadiness, weakness, lethargy, and seizures.

I have researched the Veterinary Information Boards and have included a few threads on recommendations of which insulin dogs or cats should be switched to. Please check with your veterinarian to see what you should do.

It is recommended to transition animals currently on Vetsulin to other insulins until this problem is resolved.
posted by Dr. Sherri Wilson ACVIM Small Animal Internal Medicine (1992)
“For CATS, I would change to Glargine (Lantus). As a second choice, try Detemir (Levemir)—some positive initial reports using this—seems to be very similar to Glargine but may work better in some cats. I would avoid PZI, as it is a compounded insulin–so its potency can vary from batch to batch

For DOGS, I would change to NPH as the first choice
- If there is a problem with the NPH taking too long to start working after it is injected, try 70:30 insulin (a mixture of 30% regular insulin and 70% NPH); note that this problem of delayed onset of insulin action can also be due to a post-prandial surge in the glucose levels; that can be addressed by giving insulin 30-45 minutes BEFORE the food is given (if the dog is a reliable eater)
-if there is a problem with too-short of an insulin duration with NPH, then try Glargine or Detemir, but be aware that these sometimes cause no appreciable lowering of glucose levels in some dogs and will be very expensive in large dogs

To clarify: when we change to a different insulin, there is unfortunately no predicting what dose to use for the new insulin. Different insulins have different potencies, so we have to start over (e.g. don’t transfer the same dose that you used for the Vetsulin to the new insulin).

Most endocrinologists recommend starting at 0.25-0.5 units/kg BID for a new insulin. Personally I go with the 0.5 units/kg BID. Then wait at least 1 week to run the first curve and adjust the dose accordingly.

The exception to the above is when we change to Glargine in cats—it can be remarkably more effective in dropping the glucose levels so it is recommended to do a few BG checks during the first few days on it (not complete curves) to make sure we don’t cause acute hypoglycemia.

Sherri Wilson, ACVIM (Internal Medicine)
Seattle, WA

I hope this helps

Debra Garrison, DVM