Glargine insulin for treatment of naturally occurring diabetes mellitus in dogs

Objective-To evaluate the effects of twice-daily glargine insulin administration in dogs with diabetes mellitus. Design-Open-label, prospective clinical trial. Animals-10 dogs with naturally occurring diabetes mellitus. Procedures-Dogs with poorly regulated or newly diagnosed diabetes mellitus were enrolled if their owners agreed to return them to the hospital at 1- to 3-week intervals for 4 follow-up visits. During each follow-up visit, blood glucose concentrations were measured every 2 hours for at least 10 hours after feeding a diet high in insoluble fiber and after administration of glargine insulin (time 0). The initial glargine insulin dosage was 0.5 U/kg (0.23 U/lb) SC twice daily. Results-All dogs had well-regulated diabetes mellitus at a mean +/- SD of 38 +/- 14 days (median, 43 days; range, 7 to 55 days) following study enrollment. At the time diabetes mellitus was well regulated, mean glargine insulin dosage was 0.5 +/- 0.15 U/kg (0.23 +/- 0.068 U/lb; median, 0.5 U/kg; range, 0.32 to 0.67 U/kg [0.15 to 0.30 U/lb]) twice daily, and 3 dogs were receiving a dosage < 0.4 U/kg (0.18 U/lb). In dogs with well-regulated diabetes mellitus, the mean minimum blood glucose concentration (163 +/- 89 mg/dL; 95% confidence interval, 100 to 227 mg/dL) was detected 2 hours after administration of glargine insulin and the mean maximum blood glucose concentration (230 +/- 95 mg/dL; 95% confidence interval, 64 to 323 mg/dL) was detected 12 hours after administration of glargine insulin. There was no significant difference between mean minimum and mean maximum blood glucose concentrations nor were there significant differences between blood glucose concentrations measured at other time points. Blood glucose concentration < 80 mg/dL was measured at least once in 7 of 10 dogs. Conclusions and Clinical Relevance-Results of the present study suggested that, in diabetic dogs fed a diet high in insoluble fiber, glargine insulin is a peakless insulin that does not induce a distinct blood glucose concentration nadir. For glargine insulin, 0.3 U/kg (0.136 U/lb) SC twice daily is recommended as an initial dosage.