By IV treatments I assume you mean sub q fluids. I went through this with a dog that had kidney damage due to Lyme disease that was not diagnosed in time.
Anyway, I gave her sub q fluids once a day, and it helped as it is similar to dialysis.
Kidney damage can’t be reversed. She lasted a couple of years this way, some good days, some bad days. Prescription food helped, but most supplements are a scam in my opinion.
Listen to your vet, beware of homeopathic vets, there are no miracle cures. Pain meds prescribed by the vet were helpful.
Some science based information here: http://skeptvet.com/Blog/category/herbs-and-supplements/
