Lantus is a great choice in insulin. Is the food wet or dry?
I am a little concerned over how he diagnosed the diabetes. Did he tell you what the number was?
I also am concerned about giving insulin without testing the blood first. If you shoot and he is low, he could have a hypo.
I would recommend that tomorrow before shooting you go to Walmart (I assume you are in the us) and pick up the below items so we can test him and keep him safe. If you pick up the keto-diastix you will know fast from testing his pee and confirm the diagnosis. With the below kit, you are able to test at home which is way more accurate and saves money doing it at the vet!
Getting started shopping list
1. Meter ie Walmart Relion prime, micro or confirm
2. Matching strips
3. Lancets - little sticks to poke the ear to get blood . new members usually start with a larger gauge lancet such as 28g or 29g until the ear learns to bleed. Optional - lancing tool.
4. Cotton balls to stem the blood
5. Neosporin ointment to heal the wound
6. Mini cheap flashlight - optional but useful to help see the ear veins in dark cats, and to press against
7. Ketone urine test strips ie Ketostix or ketodiastix - Important to check ketones when blood is high
8. Treats for the cat - like freeze dried chicken
9. karo syrup/corn syrup or honey if you dont have it at home - for hypo emergencies to bring blood sugar up fast
10. A couple of cans of fancy feast gravy lovers - for hypo emergencies to bring blood sugar up fast
Wendy