Poor Minnie! I have no idea why the medicine doesn't work, but you better ask your vet if he could try a different medicine. It's a serious condition! Have your flushed him with a cahteter?

Give him Hills S/D and water only!

Fister has been through this a few times, until we finally decided to have him operated.

This is one of the threads which may be of help.

Fister is on the edge again

Keeping our fingers and paws crossed for Minnie.