Which insulin formulations are preferred for canine diabetes and how should I adjust dosing based on curves?

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Lente insulin (porcine lente, Vetsulin) at 0.25 U/kg SC q12h is the recommended first-line starting dose for diabetic dogs, rounded to the nearest whole unit, with most dogs achieving control at an average of 0.5 U/kg q12h and a range of 0.2–1.0 U/kg q12h.1 Insulin glargine 300 U/mL (IGla300) administered q24h is an emerging alternative with a favorable safety profile. Glycemic control is achieved with q24h IGla300 in 72% of dogs without concurrent disease and 50% of dogs with concurrent disease.3 The starting dose is 0.5 U/kg q24h, with rapid titration facilitated by continuous glucose monitoring.3 The clinical hypoglycemia rate with IGla300 is 5% in dogs without concurrent disease — substantially lower than porcine lente (38.6%), insulin detemir (40%), and insulin glargine 100 U/mL (20%).3 Insulin degludec 100 U/mL (IDeg100) is a further basal option with a clinical hypoglycemia rate of 3%, comparable to IGla300 at 6%. The median starting dose is 0.6 U/kg, escalated to a median final dose of 1.3 U/kg over a median of 14 days.4 Median time to glycemic control with IDeg100 is shorter than IGla300 (17 days), porcine lente (35 days), IGla100 (38 days), and protamine zinc insulin (42 days).4 Insulin detemir is a long-acting option for dogs but requires particular caution due to high potency. The starting dose is 0.1 U/kg, and small dogs are at higher risk for hypoglycemic excursions.1 Dosage increases should not occur more frequently than every 1–2 weeks regardless of insulin type.1 Dose adjustment intervals and glucose curve interpretation should drive titration cadence. Insulin doses should not be increased more often than every 1–2 weeks, and a dosing window of ±2 hours on each side of the scheduled interval is acceptable.1 Continuous or flash glucose monitoring accelerates safe dose escalation for basal insulins such as IGla300 and IDeg100 by providing real-time data that traditional curves cannot.34 | Insulin | Starting Dose | Route/Frequency | Glycemic Control Ra