Veterinary Medicine - June 2008 - (Page c9)

Porcine insulin zinc suspension in the management of feline diabetes mellitus administration. Monomers and dimers can be absorbed into the bloodstream more easily than hexamers. Different insulin products liberate monomers and dimers at different rates; however, once exogenous insulin has been absorbed from the subcutaneous injection site, the origin of the insulin has no effect on its ability to function in the body. Thus, it is the insulin formulation that determines the rate and extent of absorption, and the glycemic effects in the body. The rate at which the insulin is absorbed determines its duration of action. Rapid-acting insulins are absorbed quickly; however, they also have a short duration of action. In general, shorter-acting insulins (both rapid-acting and intermediate type insulins) are more consistently and completely absorbed, which gives more predictable glycemic effects, than longacting insulins. Vetsulin contains a combination of 30% amorphous and 70% crystalline zinc insulin, has a rapid onset of action, and has an intermediate duration of action following subcutaneous administration to cats. After subcutaneous injection, the amorphous component of Vetsulin releases monomers rapidly leading to a rapid onset of e ect, whereas the crystalline component provides the intermediate duration of action due to a slower release of monomers. In the bloodstream, insulin concentrations peak about two hours after Vetsulin is administered to cats with naturally occurring diabetes mellitus.3 Plasma insulin concentrations remain elevated for about nine to 12 hours.Vetsulin has an onset of action of less than two hours in diabetic cats with peak e ects (blood glucose nadir) between 1.5 and eight hours after subcutaneous injection, although this varies between individuals.3-5 Based on blood glucose concentrations in diabetic cats,Vetsulin’s duration of action is typically between eight and 12 hours.3,5,6 “Rapid-acting and intermediate type insulins are more consistently and completely absorbed, which gives more predictable glycemic e ects than long-acting insulins. “ Safety Vetsulin can be used in diabetic cats when dosed appropriately and accompanied by adequate monitoring of the disease process.3,4,6 Hypoglycemia Regardless of the insulin origin or formulation used, any insulin dose above that required by the individual diabetic cat to control blood glucose concentrations will inevitably result in hypoglycemia.This can even occur at established doses if this is in excess of what the individual patient requires at that moment.This can be when glucose toxicity (as a result of prolonged hyperglycemia) is overcome, resulting in the individual patient requiring a lower dosage. A complicating factor, such as decreased appetite, is another possible cause of insulin excess; however, hypoglycemia in cats is usually associated with a high insulin dose.4,6 Clinical signs of hypoglycemia are not always obvious in cats, and may be restricted to lethargy. It is not uncommon for cats to show no clinical signs even when there is biochemical evidence of hypoglycemia.4,6 A dose greater than two units per cat twice a day should be used with caution, particularly in the rst one to three weeks of treatment.4,6 Cats receiving insulin should be monitored regularly and hypoglycemia treated immediately, as addressed in Feline diabetes mellitus: Important communication points (page 19). Immunogenicity Beta cell and insulin antibodies appear to be involved in the pathogenesis of diabetes in dogs and people;7,8 but do not appear to be a feature in newly diagnosed and untreated diabetic cats.9,10 Although the structure of insulin is highly conserved, variations occur in up to four insulin amino acid residues 9

Table of Contents Feed for the Digital Edition of Veterinary Medicine - June 2008

Veterinary Medicine - June 2008 Contents Leading Off Clinical Exposures Idea Exchange A Challenging Case: Conjunctival Lymphoma in a Cat Updates on Canine Hypoadrenocorticism Product Preview CE Form Advertiser Index Marketplace/Classifieds Mind Over Miller Clinical Edge - June 2008 Table of Contents Managing Diabetes Mellitus in Cats: What Makes it Work? Porcine Insulin Zinc Suspension in the Management of Feline Diabetes Mellitus Monitoring Diabetes Mellitus in Diabetic Cats Feline Diabetes Mellitus: Important Client Communication Points

Veterinary Medicine - June 2008

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