Our cat his been on Lantus for about a month but his BG remains in the 500s. He's losing weight too, we are beside ourselves and so helpless. Brought him in to the vet again 2 days ago, after they had raised the dosage from 2 units to 3 units 4 days before that. I spoke to the pharmacist at our drug store who is willing to replace the vial, he couldn't find anything to make him think it had been handled wrong on his end but is sympathetic to our situation. If the vial we have is bad for any reason would it be dangerous to give our cat the 3 units with a new vial? Now I have this new worry. So freaked out by all this.