WEBInsulin administration is the treatment of choice for diabetes mellitus in cats. For cats with newly diagnosed diabetes, protamine zinc insulin (PZI; starting dosage 0.25 U/kg [1 U/cat], SC, every 12 hours) and insulin glargine (starting dosage 0.25–0.5 U/kg [1–2 U/cat], SC, every 12 hours) are the most common insulins used (1, 2). They ...