INSULIN THERAPY IN DOGS
For newly diagnosed diabetic dogs, NPH at a starting dose of 0.5 U/kg given twice daily is recommended. Long-acting insulins
such as PZI or glargine are unpredictable in dogs and not generally recommended. A bit more information is available on the
use of detemir in dogs, but careful dosing is required, and the risk for developing hypoglycemia is high. Insulin mixtures
should be reserved for difficult cases.
INSULIN THERAPY IN CATS
Long-acting insulin products are a suitable first choice for treatment of diabetes mellitus in cats. The starting dose for
newly diagnosed patients is 0.25 to 0.5 U/kg (or 1 to 3 U/cat). A wide range of doses are used to achieve glycemic control,
so start low and work up.
Studies have reported that PZI is effective (80% to 90%) in establishing glycemic control.2,3 Glargine is also effective in achieving good glycemic control in cats.4 Several studies have attempted to compare the rates of remission based on the type of insulin used, and while in small studies
there has been evidence that cats treated with glargine may be more likely to achieve remission, this finding needs to be
replicated in larger studies.5
Cats should be carefully monitored for the development of hypoglycemia because of the possibility of remission, and a blood
glucose curve should be performed five to 14 days after any change in insulin formulation or dose.
Since intermediate-acting insulin such as Lente are generally more potent than the long-acting insulin products, they may
be a better choice for patients with concurrent illnesses that can cause insulin resistance or that may make cats prone to
Regardless of insulin formulation, twice-a-day dosing is more likely to result in good glycemic control. In addition, once-a-day
dosing can increase the risk for hypoglycemia.
MONITORING INSULIN THERAPY IN DIABETIC PATIENTS
Always wait a minimum of seven days before increasing an insulin dose, and spot-check the blood glucose concentration in the
first 24 to 48 hours after any change to detect hypoglycemia.
To evaluate a patient's response to insulin therapy, be sure consider changes in clinical signs, blood glucose curves, urine
glucose concentrations, and fructosamine concentrations. Therapy changes should be based on all of these parameters. An increased
blood glucose concentration may be short-lived, so it is important to look at all of the information before changing insulin
dosage or formulation. Then, adjust the dose as needed and reevaluate.
Home monitoring is advisable in many cases, but some owners will go overboard with their level of blood glucose monitoring,
so make sure that you are seeing those patients in the clinic from time to time and advising owners appropriately. It is also
good to remember that all blood glucose meters are not the same. The ease of use and blood volume required can vary from brand
to brand, so become accustomed to one type and be consistent. Another consideration is that human blood glucose meters have
a built in bias at lower concentrations. They are still useful for dogs and cats, but this bias must be taken into consideration.
Based on a University of California-Davis study, the most precise meters for dogs and cats are the Alpha Track (Abbott) and
the One Touch Ultra (LifeScan).6
Remission in cats
Diabetes mellitus in cats can be transient or intermittent. Several studies have reported spontaneous remission of diabetes
in cats after weight loss and good glycemic control was achieved.4,5 However, the rates of remission in these studies varied widely (17% to 64%). Diabetic cats that achieve remission should
not be considered normal; care must be taken to watch for the return of clinical signs. The length of remission varies from
one to two months to the rest of their lives. Many cats will go in and out of remission, so we should be careful in discussing
the possibility of remission with owners of diabetic cats since a half to a third of cats that go into remission will relapse.4,7,8