Intervet/Schering-Plough Animal Health (ISP) is urging veterinarians to transition their diabetic patients off of its veterinary insulin product, Vetsulin. The company is advising veterinarians to be cautious in the transition to other insulin products in order to avoid complications. And company representatives also said that practices can obtain refunds on unopened vials of the product.

The U.S. Food and Drug Administration (FDA), along with ISP, issued a product alert on Vetsulin, after batches of the product were found to be out of specification. Vetsulin, a porcine insulin zinc suspension used to treat diabetes in dogs and cats, contains crystalline insulin and amorphous insulin. The concentration of the crystalline component was higher than what is outlined in the specifications of the product, the company said, which “could potentially result in your patients experiencing a delay in the onset of action, a delay in peak activity, and an overall extension of the duration of activity.” However, the company also noted that no occurrences of this have been documented.

In a conference call Nov. 10, Intervet/Schering-Plough representatives addressed veterinary industry professionals regarding this issue. They said Vetsulin would continue to be manufactured, but supplies in the United States will be limited. The company said that veterinarians should begin to transition their current patients using Vetsulin to other insulin products, and any new patients should not be started on Vetsulin.

With about 300,000 dogs and cats currently using Vetsulin, company representatives suggested that transitioning patients could take some time, so the product will still be available to facilitate a smooth transition. Although no increases in adverse event rates of efficacy issues have been documented, the FDA and ISP are requesting that veterinarians closely monitor patients receiving Vetsulin for any changes in onset or duration of activity, or for any signs of hyperglycemia or hypoglycemia.

In response to a question from a caller, the company noted that while the FDA (in conjunction with ISP) had issued an alert on Vetsulin, regulatory agencies in the more than 30 other countries where it is sold (under the name Caninsulin) had not taken any similar action.

Veterinarians in the United States who have unopened vials of Vetsulin can obtain refunds for that inventory, the company said. To get the refund, practices should contact their point of purchase. In addition, the company said it would offer refunds for Vetsulin syringes. Vetsulin is administered in U-40 syringes, in contrast to human insulin formulations, which are administered in U-100 syringes.

The American Animal Hospital Association (AAHA) will be issuing a letter to its members in the near future, with recommendations on how best to implement the transition from Vetsulin to other insulin products. Check back on the AAHA website for details in the next few days. Vetsulin is the only FDA-approved drug for treating diabetes mellitus in dogs and cats, so alternatives would be off-label uses of different products, such as those approved for human use.

In the meantime, veterinarians with questions or concerns about Vetsulin are encouraged to check www.vetsulin.com for information or contact ISP Technical Services at (800) 224-5318.