Linda answered on your other thread. Many members in the US order from Marks Marine Pharmacy in Canada. One suggestion if you need to start insulin ASAP is to ask your vet for two prescriptions. One will be for the package of pens you will order from Marks and the other one for a single pen to get started with. Also if you take to the vet for them to check if he needs to start insulin after the diet change, the glucose reading probably will be higher than if you were testing at home. Stress can raise glucose levels so the reading at the vet will not be as accurate as your tests will be.