The Kidney is no organ to mess with. No matter what you do, be sure to STAY HYDRATED!!! Especially if you plan on using a protien suppliment. I don't think I would recommend creatine as it is eliminated by the kidney and may cause dehydration. Hmmm, definately use a good multi, fairly clean calorie rich foods, heavy ass weights...wait for the ok from your doc. best of luck man!