Was wondering about Caffeine on a 26 year old with multiple kidney problems and kidney transplant, should I cut Caffeine out completely does it have any effect on kidneys? and if so what? I ask here because its strange my doctor told me it was ok to drink nothing but diet pepsi, I found this to be strange but my vitals over the last 6 months of drinking nothing but Diet pepsi have been perfect so just curious, Thanks
So is there any negetive effects of the Soda and if not should i just increase my intake of water?

Ok and also, if soda is out, is Coffee with fat free creamer an ok substitute? I need some pick me up because the pills i am on slow me so much its unbearable