Placebo versus allopurinol for renal calculi.

Certain patients with recurrent calcium oxalate calculi will show a mild uricacidemia and/or uricosuria. A prospective blind study was begun in 1970, comparing placebo to allopurinol in the management of these patients. The 92 patients had been followed for a minimum of 6 months to 5 years before the code was broken. It is demonstrated clearly that there is a placebo effect in the management of renal calculous disease. It also has been shown that the only event that clearly separates the 2 groups is complete cessation of calculous formation. Allopurinol is effective in 61 per cent of the patients and these successes usually can be identified after 1 year of treatment.