The cat I recently lost after 19 years got diabetes when she was 11 or 12, but it was controlled by using a wet canned food with no sauces, high protein and under 10% carbs. But when she was 17 she got kidney failure. While there is basically no meds in Sweden for treatment for cats with kidney failure I joined an on line group and they helped a lot. These cats often have constipation. Miralax is not sold or allowed in Sweden but I got it into the country. She got about tsp 2 times a day. I began with 1/8th of a tsp and just added to it until her stool was good. It works well. The only thing they have here is a paraffin wax that is liquid and the cat gets it but it coats the stomach so NO food is digested it just passes on through with no nutrition.