Abstract: Background Insulin lispro is a rapid acting insulin analog that is used as postprandial bolus insulin in humans. It may also be useful as a postprandial bolus insulin in dogs and has been suggested for use in the treatment of diabetic ketoacidosis (DKA), however, limited pharmacodynamic (PD) data exists. Objective To determine the PD of insulin lispro following subcutaneous injection in dogs. Animals Seven healthy, female spayed, two-year-old purpose-bred beagles (median weight 8.9 kg [7.8-9.6]). Methods Each dog received 0.2 IU/kg insulin lispro subcutaneously. Isoglycemic clamps were performed by variable rate of intravenous glucose infusion. Blood glucose was measured by AlphaTrak3 every five minutes, and the glucose infusion rate (GIR) was adjusted to maintain baseline glycemic level. The GIR over time was used to create a time-action curve. The data were evaluated for normality using the Shapiro-Wilk Test. Data were not normally distributed and are therefore presented as median [range]. Results Insulin lispro had a median onset of action of 10 minutes [10-15] and median duration of action of 150 minutes [115-300]. The median peak insulin action, defined as GIR max, was 19.1 mg/kg/min [12.9-26.9], and the median time to peak insulin action (time to GIR max) was 65 minutes [40-80]. Conclusion The rapid onset and short duration of insulin lispro make it impractical as a postprandial insulin for dogs but suggest utility for managing DKA. Further studies are needed to evaluate the PD of insulin lispro in dogs with DKA, as disease state may alter its time-action profile.
