Veterinary Medicine - June 2008 - (Page c5)

Managing diabetes mellitus in cats: What makes it work? insulin that many practitioners considered to be the insulin of choice for cats because of its molecular similarity to feline insulin. However, the PZI insulin approved for use in the United States (PZI VET—IDEXX Pharmaceuticals) has been discontinued as of April 2008. Caninsulin is an intermediate-acting porcine insulin that has been available for more than 15 years in Australia, Canada, and Europe. It has recently been released in the United States as Vetsulin. It has just received FDA approval for use in cats and is therefore the only insulin licensed for this species. Its peak activity is at about three hours and it has a duration of action of about eight hours.16,17 Insulin glargine (Lantus—sano aventis) is a long-acting human recombinant insulin analog that forms microprecipitates at the site of injection from which small amounts of insulin glargine are slowly released.Thus the glucose nadir occurs later than with intermediate-acting insulin. Lantus is di erent from other longacting forms of insulin in that it starts to work within one to two hours, continues acting for about 24 hours, and does not have a peak e ect. Dose. While guidelines exist for choosing the starting dose of insulin for a cat, the maximum dose will be the dose needed to resolve the clinical signs of excessive urination and drinking, lethargy, and weakness.The majority of cats require twice daily injections, regardless of the insulin selected. Diet Table 1. Absolute or relative insulin de ciency levels* Level of insulin de ciency Normal E ects Secreted insulin enables primary tissues (liver, muscle, fat) to take up, utilize, and store the ingested nutrients (glucose, fat, and amino acids). Decreased transfer of ingested nutrients into tissues causes mild or moderate hyperglycemia. Deﬁciency causes decreased tissue uptake of ingested nutrients, glucose overproduction, and excessive mobilization of the body’s protein and fat storages. Increased fatty acid delivery and oxidation by the liver results in ketoacidosis. Mild Severe Marked * Peterson ME, Randolph JF, Mooney CT. Endocrine diseases. Sherding RG, ed. In: The cat: diseases and clinical management. 2nd ed. Churchill Livingstone Inc, 1994;1465-1479. It’s also important to counsel clients on the recommended diet. In the past, veterinarians recommended high- ber diets because they believed these were absorbed more slowly, helping to regulate blood glucose levels.This does not seem to be the case for cats. Lower carbohydrate diets may be as—or more—e ective.18 Currently, there is also interest in higher-protein diets to improve blood glucose regulation. Recent studies that looked at the effects of feeding di erent diets on glycemic control in cats support the use of low- ber, low-carbohydrate diets. Diabetic cats in one study were signi cantly more likely to revert to a noninsulin-dependent state when fed the low- ber, low-carbohydrate canned diets vs. the moderate-carbohydrate high- ber diets.19 Another study looked at feeding highcarbohydrate diets compared with high-fat diets and found that cats on the high-fat diet showed a slightly elongated glucose clearance and reduced acute insulin response to glucose administration.20 So ber may be bene cial in some cats.21 No one really knows if there is a single diet recommendation that can be made that will bene t all diabetic cats. Keep in mind that diets may need to be adjusted when regulating an 5

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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