I have never had a kidney stone and I'm 43 yrs. old. I started taking Lithium in March of 2009. Since summer of 2009, the creatine in my urine has been slightly elevated. In January of this year, my kidney function was only at 56%, so my primary Dr. sent me to a specialist who did 3 tests to find out I had a kidney stone in my left tube leading from kidney that measured 2mm. She shocked the stone, but said there were several smaller stones higher up in that same kidney. She also put a stent in to keep the tube from collapsing. She also told me that the lodged stone had grown from 2mm to 1 cm in one week!! It had been lodged for a long time. The x-ray she did the day of surgery revealed another large impassible stone in the right kidney. So after the left kidney heals, I have to have surgery again. I drink a ton of water and except for milk water only, and nothing else has changed except starting the lithium in March of 2009. I'm really hoping this isn't the cause and I would have to stop taking the Lithium cuz it's my miracle med. and I only take 450 mg a day becuz of sensitivity to it, but it does it's job.