2020 Volume 33 Issue 2 Pages 157-161
Sulfamethoxazole-trimethoprim (ST) therapy inhibits renal tubular creatinine (Cr) secretion, thereby decreasing creatinine clearance (Ccr). The patient was a 9-year-old girl who was diagnosed with neuroblastoma originating from the right adrenal gland at 4 years of age and underwent multidisciplinary therapy. The patient had recurrent infections after the completion of therapy and was taking oral ST prophylactically. She developed drug-induced Fanconi syndrome in the course of the multidisciplinary therapy, and her renal function decreased after the completion of this treatment. Discrepancies between the estimated glomerular filtration rates (eGFR) based on Cr, cystatin C, and β2-microglobulin were observed; thus, an inulin clearance test (Cin) was performed to accurately assess her renal function. Although GFR measured by Cin is normally lower than that measured by Ccr, the 2-h Ccr and Cin levels were similar(22.1 ml/min/1.73 m2). This presumably occurred as a result of ST therapy, which inhibited the secretion of Cr in the renal tubules to lower Ccr to a level close to that of Cin.
