Did the vet do a cystocentesis and run a culture and sensitivity? It may be that whatever bacteria is causing the UTI isn't being treated by the clavamox. I'm also not a fan of Convenia. If you've not seen this before, it's a post on Dr. Lisa's site about the
risks associated with Convenia. My vet won't prescribe it.
I'll be curious what the curve looks like. While Misty has definitely been seeing some low numbers, she's bouncing like crazy. I'm wondering whether a fatter dose would help.
Have you given any thought to posting on the Lantus/Lev/Biosimilar board?