In a 2009 study reported in the Journal of Alternative & Complementary Medicine, inosine at doses ranging from 1000 mg to 3000 mg were given to MS patients daily for one year. There were only 16 patients, and four of them, or 25%, developed kidney stones due to raised serum urate levels. Not sure if anything valid can be concluded from such a small study, but it supports what mrsD said earlier in the thread about inosine and raised uric acid levels.