Changing Brand of NPH Insulin May Disrupt Diabetic Control

Treating dogs and cats with diabetes can be challenging but this article— Changing insulin brands may disrupt diabetics— published on the Veterinary Information News Service points out another issue to complicate treatment of this common disease (1).

In dogs, we commonly use human NPH insulin, which is an intermediate-acting insulin preparation (2,3). This insulin does not work well in cats, and I do not recommend using it for initial treatment of feline diabetes.

Two brands of NPH insulin are on the market: Humulin N, made by Eli Lilly and Co. and Novolin N, made by Novo Nordisk Inc. (2-4). Although both contain NPH insulin, Humulin and Novolin are made using different ingredients and manufacturing techniques, so they are not exactly the same. A number of owners and veterinarians around the country have reported in recent months cases of dogs whose insulin brands were switched developing out-of-control blood glucose levels, a potentially life-threatening condition that can be expensive to remedy.

Most diabetic cats are treated with either insulin glargine (Lantus) or PZI insulin (ProZinc), both long-acting insulin preparations (5-7). Only one brand of these insulin preparations exists, so this will not ever be a problem.

References:

1. Lau E. Changing insulin brands may disrupt diabetes. The VIN News Service, February 5, 2013.
2. Peterson ME. Blog Post, Insights to Veterinary Endocrinology. Insulin Choice for the Diabetic Dog and Cat: Which is Best? h 
3. Palm CA, Boston RC, Refsal KR, et al. An investigation of the action of Neutral Protamine Hagedorn human analogue insulin in dogs with naturally occurring diabetes mellitus. Journal of Veterinary Internal Medicine 2009;23:50-55. 
4. American Diabetes Association. Insulin administration. Diabetes Care. 2004;27 (Suppl 1):S106-9. 
5. Gilor C, Graves TK. Synthetic insulin analogs and their use in dogs and cats. Veterinary Clinics of North America: Small Animal Practice 2010; 40:297-307. 
6. Nelson RW, Henley K, Cole C, et al. Field safety and efficacy of protamine zinc recombinant human insulin for treatment of diabetes mellitus in cats. Journal of Veterinary Internal Medicine 2009;23:787–793. 
7. Norsworthy GD, Lynn R, Cole C. Preliminary study of protamine zinc recombinant insulin for treatment of diabetes mellitus in cats. Veterinary Therapeutics 2009;10:24–28.