Unregulated diabetes does cause neuropathy in both people and cats. Regulating BG does improve or eliminate neuropathy in most cases. However, many people with neuropathy continue to have some symptoms even if they are regulated. From reading this forum, Ithere are also people with cats who are regulated but still have neuropathy. It would certainly make sence for someone to try better regulation and B12 first. However, it would also be good to know there are other alternatives if the first line of treatments don't work.
I did some more research on neuropathy-besides diabetes there are also many other conditions that can cause neuropathy or neuropathy like symptoms. For example, many people who are treated with certain types of chemotheraphy can get the symptoms. So I guess the lesson is that even if a person or cat is diabetic, it doesn't always mean the neuropathy type symptoms are comming from their diabetes.
Cymbalta works good for some people and maybe in dogs? I know a lot of medications used in dogs might not be appropriate for cats. Many drugs that originally developed for human use eventually filtered down to vet use.Lantus and Levemir are forms of human insulin. We shouldn't automatically rule out something because it would be an off label use.