Effect of sodium‐glucose cotransporter 2 inhibitor canagliflozin on interstitial glucose concentration in insulin‐treated diabetic dogs

Abstract Background The utility of sodium‐glucose cotransporter 2 inhibitors (SGLT2i) has not been reported in insulin‐treated diabetic dogs. Hypothesis Canagliflozin, a PO‐administered SGLT2i, decreases interstitial glucose concentration (IG) in insulin‐treated diabetic dogs. Animals Five insulin‐treated diabetic dogs. Methods Uncontrolled open label longitudinal study. Canagliflozin (2‐4 mg/kg/day PO) was added to an unchanged insulin dose for 7 days. Fractional excretion of glucose was calculated by dividing the product of urine glucose and serum creatinine concentrations by the product of serum glucose and urine creatinine concentrations. Hypoglycemia was defined as IG <60 mg/dL. Results Median IG in 2869 measurements obtained while dogs were treated with insulin and canagliflozin was 87 mg/dL (range, 40‐500 mg/dL) and was significantly lower than median IG in 1426 measurements obtained while dogs were treated with insulin alone (212 mg/dL; range, 41‐500 mg/dL; P < .001). Median fractional excretion of glucose when dogs were treated with insulin and canagliflozin was 1.1% (range, 0.9%‐2.0%), significantly higher than when dogs were treated with insulin alone (0.3%; range, 0.01%‐1.0%; P = .04). The frequency of hypoglycemia was higher in dogs treated with insulin and canagliflozin (544 of 2869 IG measurements, 19%) compared with the frequency of hypoglycemia in dogs treated with insulin alone (52 of 1426 IG measurements, 4%; P < .001). Conclusions and Clinical Importance Canagliflozin may have a role in improving glycemic control in insulin‐treated diabetic dogs, but the dose of insulin should be decreased when adding canagliflozin to insulin treatment.