My 6 and a half year old westie has had Addison's disease for about 3 years recently he relapsed I took him to the vet and had IV fluids and was normal again. I went back to have him checked and his potassium and sodium were elevated again Along with his BUN and creatine my vet is suspecting renal damage. He has been on prescription diet for the passed two weeks along with kidney supplements and nothing seems to help his kidney numbers decrease. I asked my vet if maybe the florinef is increased it will help his potassium and sodium go down and help his kidneys. He said no that the kidneys aren't filtering. My dog also has a low concentration level in his urine. Can someone give me there opinion as to if this is renal failure or his Addison's disease. I've heard that addisons can be mistaken for renal failure. My vet told me he is at the max amount of florinef he should be taking for his size. He takes 1 pill in the morning an one at night.