2. PZI insulin: As with dogs, I recommend using PZI Vet. The initial starting dose is 1 to 3 U/cat given subcutaneously once a day.4 However, in my experience, most cats will need twice-a-day administration. In my experience, remission rates are 40% to
50% within three or four months of starting treatment when this insulin is used in conjunction with a low-carbohydrate, high-protein
3. Humulin N (Eli Lilly): In my experience, remission rates are 40% to 50% when this insulin is used with a low-carbohydrate, high-protein diet. Starting
doses are generally 1 to 3 U/cat given subcutaneously twice a day.
4. Vetsulin (Intervet): I have seen remission rates of 40% to 50% when this insulin is used with a low-carbohydrate, high-protein diet in cats. Starting
doses are generally 1 to 3 U/cat given subcutaneously twice a day.5 This product is not approved for use in cats.
In cats that are receiving either Humulin L Lente or Humulin U Ultralente, I recommend switching to either PZI Vet, Vetsulin,
or Humulin N. The initial starting dose remains the same as stated above for newly diagnosed patients. Reassess the cat's
clinical signs and perform a serial blood glucose curve one week after changing insulin preparations. If you wish to switch
to glargine, follow the dosage recommendations as outlined above under newly diagnosed cases. Note that remission rates will
be much lower with glargine and a low-carbohydrate, high-protein diet in long-standing diabetic patients (cats with diabetes
for more than six months) than in patients in which diabetes has been newly diagnosed.
David S. Bruyette, DVM, DACVIM (internal medicine), is a Veterinary Medicine Editorial Advisory Board member and the medical director of VCA West Los Angeles Animal Hospital in Los Angeles, Calif.
1. Marshall R, Rand J. Comparison of the pharmacokinetics and pharmacodynamics of glargine, protamine zinc, and porcine lente
insulin in healthy cats, in Proceedings. Aust Coll Vet Scientists Sci Week 2003.
2. Stenner VJ, Fleeman LM, Rand JS. Comparison of the pharmacodynamics and pharmacokinetics of subcutaneous glargine, protamine
zinc and lente insulin preparations in healthy dogs (abst). J Vet Intern Med 2004;18:444-445.
3. Marshall RD, Rand JS. Treatment with glargine results in higher remission rates than Lente or protamine zinc insulins in
newly diagnosed diabetic cats (abst). J Vet Intern Med 2005;19:425.
4. Nelson RW, Lynn RC, Wagner-Mann CC, et al. Efficacy of protamine zinc insulin for treatment of diabetes mellitus in cats.
J Am Vet Med Assoc 2001;218:38-42.
5. Martin GJ, Rand JS. Pharmacology of a 40 IU/ml porcine lente insulin preparation in diabetic cats: findings during the first
week and after 5 or 9 weeks of therapy. J Feline Med Surg 2001;3:23-30.