Thank you for responding and sharing your wisdom Superchemicalgirl and Penny1960
Yes, I'm using a U40 on him. We kicked him back to 3 units BID. I feel guilty. It's the first time I've ever countered a vets RX but he isn't living with the little guy and seeing how he is acting.
Penny, first and foremost, take care of yourself.
Don't feel bad. The package insert says to start with 1-2 units q12, not 3. You know your animals better than the vet does, and frankly my vet trusts me. She Rxed some prednisolone for the sick cat I had and gave me general instructions and told me to titrate to effect. Now, she did know the cat lived with 2 pharmacists, but the vet also trusts that we know what's best and can see how the animal is acting. I think yours would feel the same way.