Effect of cyclosporin A on glomerular filtration rate in children with minimal change nephrotic syndrome.

Cyclosporin A (CyA) is now commonly used in the management of children with steroid-dependent nephrotic syndrome. In order to assess nephrotoxicity related to CyA therapy, we measured glomerular filtration rate (GFR) on 123 occasions in 24 children with minimal change nephrotic syndrome receiving CyA. GFR was estimated from the plasma clearance of 51chromium-EDTA every 3 months during CyA therapy of up to 27 months duration. There was a significant reduction in GFR after 3 months of CyA therapy [118 +/- 33 (SD) to 93 +/- 24 ml/min per 1.73 m2] but no further fall thereafter, although the reduction in GFR was sustained for the duration of CyA therapy. This reduction in GFR appeared to be reversible upon cessation of CyA, but careful monitoring of renal function is necessary in such patients to prevent the development of longer term nephrotoxic sequelae.