Effect of Once-Daily Insulin Glargine U300 in Diabetic Dogs

In the Literature

Tardo AM, Fleeman LM, Fracassi F, Berg AS, Guarino AL, Gilor C. A dose titration protocol for once-daily insulin glargine 300 U/mL for the treatment of diabetes mellitus in dogs. J Vet Intern Med. 2024;38(4):2120-2128. doi:10.1111/jvim.17106

The Research …

Diabetes mellitus (DM) is a common endocrinopathy in dogs that has historically necessitated lifelong, twice-daily insulin injections and therapeutic dietary modification; however, insulin glargine U300 (GU300) is increasingly used in veterinary medicine because it has an action profile more consistent with a basal (ie, peakless) insulin.¹ GU300 is more concentrated but less potent than glargine U100; therefore, the physiologic effect of a dose of GU300 is not 3 times that of the same dose of glargine U100.

The current study evaluated administration of GU300 in 95 dogs with newly diagnosed (15%) or previously treated (85%) DM. Diets were not standardized, and 60% of dogs had comorbidities. A starting dose of 0.5 U/kg SC every 24 hours was used for newly diagnosed patients, and the median dose for all dogs was 0.8 U/kg SC every 24 hours. Flash continuous glucose monitoring was used to allow rapid dose determination. Investigators followed standardized guidelines to adjust doses until hyperglycemia was controlled.

Of all dogs, 59% were maintained on once-daily GU300, and 41% required a transition to twice-daily administration; the median dose for both groups at the end of the study was 1.9 U/kg per day. Significant postprandial hyperglycemia occurred in 5% of dogs and was treated with once- or twice-daily bolus insulin administration (porcine lente or 70/30 neutral protamine Hagedorn/regular insulin mix). Median time to achieve glycemic control was 16 days (72% achieved control in ≤30 days), and level of control was characterized as excellent, good, or moderate in 65%, 26%, and 7% of cases, respectively. Clinical hypoglycemia occurred in 6% of all dogs. Once-daily therapy was sufficient for maintenance in 72% of dogs without comorbidities, compared with 50% of dogs with comorbidities.

…The Takeaways

Key pearls to put into practice:

• GU300 provided good to excellent glycemic control in 91% of dogs with DM. Most were maintained on once-daily therapy. GU300 can be considered for diabetic dogs, especially when twice-daily administration is difficult or wide glycemic excursions occur with administration of another insulin type. GU300 may not require administration with meals.

• The lower potency of GU300 should be acknowledged when determining doses to avoid the assumption that action will be 3 times that of glargine U100. Due to variability in dose requirements and response, GU300 is initially best monitored via continuous glucose monitoring to facilitate rapid dose determination and control of hyperglycemia while minimizing risk for hypoglycemia.

• Pet owners should be aware that once-daily GU300 administration is not guaranteed; some dogs may require twice-daily administration and/or addition of mealtime insulin injections if significant postprandial hyperglycemia occurs.

• Dogs with comorbidities were less likely to be maintained on once-daily GU300 compared with dogs without comorbidities; however, median daily insulin dose, rates of good or excellent glycemic control, and time to achieve glycemic control did not differ between groups.