Treatment of cystinuria with alpha-mercaptopropionylglycine.

Four cystinuric patients (3 females and 1 male) with recurrent L-cystine stone formation were treated with alpha-mercaptopropionyl glycine (MPG). In one patient the treatment was stopped because of a rash developing after one week of treatment. In the other 3 patients MPG was found to be as effective as penicillamine in lowering the urinary cystine excretion to safe levels. No serious side effects of the drug were recorded.