To the Editor.—Sloand and Izzo1 described dramatic reductions in cystine excretion with captopril therapy. We subsequently treated a homozygous cystinuric patient with captopril but were unable to confirm their results.
Report of a Case.—A 29-year-old man presented in May 1980 with three episodes of renal colic and stone analysis showing pure cystine. Urine collection revealed 3111 μmol of cystine per day and 835 mg of creatinine per day. He was treated with
high fluid intake and alkali therapy. Yearly roentgenograms were normal until September 1987, when he was found to have an obstructing right-sided ureteropelvic stone. Percutaneous nephrostomy and nephrolithotomy were successful in removing another pure cystine stone.
Captopril therapy was begun on Oct 8, 1987, and increased over a six-day period to 50 mg three times daily without side effects. This dose was continued until Jan 15, 1988. The results of serial 24-hour urine studies are illustrated