• Open Access

Field Safety and Efficacy of Protamine Zinc Recombinant Human Insulin for Treatment of Diabetes Mellitus in Cats


  • The PZIR clinical study group comprised clinicians who investigated protamine zinc recombinant human insulin for the purpose of obtaining FDA approval for treatment of cats with diabetes mellitus. In addition to Drs Nelson, Henley, and Cole, other veterinarian members of the group were Kevin Barcus, Noemi Benitah, Marc Bercovitch, Adrianne Brode, Cheryl Burke, Bonnie Cate, Marcia Chastain, Jeff Dennis, Gary Edlin, Deborah Edwards, Scott Linick, Harrison Monk, Jean Pitcarin, James Prueter, Michelle Purnell, Michael Radcliffe, Roger Sifferman, and Jennifer Usiak.

Corresponding author: Richard W. Nelson, Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616; email: rwnelson@ucdavis.edu.


Background: This study describes the efficacy of a new protamine zinc recombinant human insulin (PZIR) preparation for treating diabetic cats.

Objective: To evaluate effects of PZIR on control of glycemia in cats with newly diagnosed or poorly controlled diabetes mellitus.

Animals: One hundred and thirty-three diabetic cats 120 newly diagnosed and 13 previously treated.

Methods: Prospective, uncontrolled clinical trial. Cats were treated with PZIR twice daily for 45 days. Control of glycemia was assessed on days 7, 14, 30, and 45 by evaluation of change in water consumption, frequency of urination, appetite, and body weight, serum fructosamine concentration, and blood glucose concentrations determined 1, 3, 5, 7, and 9 hours after administration of PZIR. Adjustments in dosage of PZIR were made as needed to control glycemia.

Results: PZIR administration resulted in a significant decrease in 9-hour mean blood glucose (199 ± 114 versus 417 ± 83 mg/dL, X± SD, P < .001) and serum fructosamine (375 ± 117 versus 505 ± 96 μmol/L, P < .001) concentration and a significant increase in mean body weight (5.9 ± 1.4 versus 5.4 ± 1.5 kg, P= .017) in 133 diabetic cats at day 45 compared with day 0, respectively. By day 45, polyuria and polydipsia had improved in 79% (105 of 133), 89% (118 of 133) had a good body condition, and 9-hour mean blood glucose concentration, serum fructosamine concentration, or both had improved in 84% (112 of 133) of the cats compared with day 0. Hypoglycemia (<80 mg/dL) was identified in 151 of 678, 9-hour serial blood glucose determinations and in 85 of 133 diabetic cats. Hypoglycemia causing clinical signs was confirmed in 2 diabetic cats.

Conclusions and Clinical Relevance: PZIR is effective for controlling glycemia in diabetic cats and can be used as an initial treatment or as an alternative treatment in diabetic cats that do not respond to treatment with other insulin preparations.