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  1. Product Safety Information

ProZinc (protamine zinc recombinant human insulin) - Veterinarians

February 8, 2019

Dear Veterinarian:

The U.S. Food and Drug Administration (FDA) has approved Boehringer Ingelheim Animal Health Inc.’s ProZinc (protamine zinc recombinant human insulin) for the reduction of hyperglycemia and hyperglycemia-associated clinical signs in dogs with diabetes mellitus. This product was already approved for use in cats for the same indication. ProZinc has not been evaluated for use in humans. Now, there are two drug products specifically approved for the management of diabetes mellitus in dogs, ProZinc and Merck Animal Health’s Vetsulin (porcine insulin zinc suspension).

The FDA would like to emphasize the benefits of using FDA-approved drugs in your practice, and of the bioavailability concerns associated with compounded insulin preparations. FDA-approved drugs have been demonstrated to be safe and effective for their intended use. In addition, there has been demonstrated consistency in the manufacturing of FDA-approved products, for example, to preserve the drug’s identity, strength, quality and purity. The FDA strongly encourages use of an FDA-approved veterinary insulin drug product for newly diagnosed diabetic dogs, or when considering transitioning patients from one product to another.

Manufactured for Boehringer Ingelheim Animal Health Inc., ProZinc is a prescription animal drug product containing 40 international units (IU) insulin/mL and is intended for subcutaneous injection using a U-40 syringe. The recommended starting dose in dogs is 0.2-0.5 IU insulin/pound of body weight (0.5-1.0 IU/kg) once daily. Each dose should be given concurrently with or right after a meal. You should re-evaluate the dog at appropriate intervals and adjust the dose and frequency based on both clinical signs and laboratory parameters (mean and minimum blood glucose and fructosamine) until adequate glycemic control has been attained. Please refer to the Freedom of Information Summary and package insert for ProZinc before using this product.

Benefits of FDA Approval

The FDA rigorously evaluates an animal drug before determining whether to issue an approval. As part of the approval process, the drug company must prove to the FDA that:

  • The drug is safe and effective for a specific use in a specific animal species;
  • The manufacturing process is adequate to preserve the drug’s identity, strength, quality, and purity from lot-to-lot for a consistent product; and
  • The drug’s labeling is truthful and not misleading.

The FDA’s role does not stop after the agency approves an animal drug. As long as the drug company markets the animal drug, the agency continues to monitor:

  • The drug’s safety and effectiveness. Sometimes, the agency’s post-approval monitoring uncovers safety and effectiveness issues that were unknown at the time of approval;
  • The manufacturing process to ensure quality and consistency are maintained;
  • The drug’s labeling to make sure the information remains truthful and not misleading; and
  • The company’s marketing communications related to the drug to make sure the information is truthful and not misleading.

Adverse Drug Events Associated with ProZinc in Dogs

ProZinc is contraindicated in dogs sensitive to protamine zinc recombinant human insulin or any other ingredients in ProZinc. ProZinc is contraindicated during episodes of hypoglycemia.

In a 182-day clinical field study, 276 dogs received ProZinc. The most common adverse reactions were lethargy, anorexia, hypoglycemia, vomiting, seizures, shaking, diarrhea, and ataxia. Please see Table II.3 in the Freedom for Information Summary for more information.

Safety and Effectiveness of ProZinc Compared to Compounded Forms of Insulin

Compounded animal drug preparations are not FDA-approved drugs, nor are they FDA-approved generic drugs. Unlike FDA-approved ProZinc, compounded formulations of insulin have not been evaluated by the FDA for safety or effectiveness and may vary in quality and potency. The absorption and effectiveness of ProZinc has been demonstrated. In contrast, the absorption and bioavailability of compounded formulations of insulin are unknown and may be inadequate or variable, making disease management more challenging.

The effectiveness of ProZinc was demonstrated in one adequate and well-controlled 84-day clinical field study in client-owned dogs followed by a 98-day extended-use phase with 276 dogs receiving ProZinc. Two hundred twenty-four (224) dogs were included in the effectiveness analysis. Dogs were started on ProZinc at a dose of 0.2-0.5 IU/lb (0.5-1.0 IU/kg) once daily. Effectiveness was based on successful control of diabetes, which was defined as improvement in at least one laboratory parameter (blood glucose curve mean, blood glucose curve minimum, or fructosamine) and at least one clinical sign (polyuria, polydipsia, or body weight loss). Based on this definition, 162 of 224 cases (72%) were considered successful.

The FDA’s Center for Veterinary Medicine (CVM) is committed to promoting and protecting animal health by ensuring safe and effective drugs are available for animals. For more information, please contact CVM’s Education & Outreach Staff at 240-402-7002 or AskCVM@fda.hhs.gov.


FDA’s Center for Veterinary Medicine

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