[Renal pelvis stones made of glafenic acid in two patients under prolonged treatment with analgesics (author's transl)].

Two women aged 62 and 69 years who had been taking glafenine at normal dosage over a period of 4 years developed a renal calculus. In the first case, 6 small slightly radioopaque stones were extracted by pyelotomy, presenting a crystalline surface and yellow, soft, and amorphous section. They consisted of 50% calcium oxalate, 33% glafenic acid, and 10% proteins. In the second case, pyelography showed a sizable round and radiotransparent defect in the renal pelvis. At pyelotomy, a large, soft, and greenish stone was extracted, presenting a yellow and amorphous section, without calcium, but consisting of 75% glafenic acid, and 25% proteins. Through IR spectrography, glafenine metabolites found in the stones represented 33% in our first case and 75% in our second case. Through other methods, such as UV spectrophotometry and chromatography, 26% and 61% are respectively found. The metabolites are glafenic acid and hydroglafenic acid, in an identical proportion of 9 to 1 in both cases.