Years ago, when my cat Max was first diagnosed and before he went into remission the first time, he was up to 4 units of PZI (different insulin than Lantus), then I read on this site about the importance of low carb wet food and switched Max. When I totally stopped the dry MD, it was almost like overnight that he went from almost 4 units to 1 unit and then to even less. Just like others have said, drop the dose and watch and test and breathe. It takes time for the cat to settle into #'s when starting insulin and it takes patience.