Corticosteroid- and furosemide-induced increase in proteinuria in nephrosis.

A corticosteroid- and furosemide-induced excessive increase in proteinuria developed in a 34-year-old nephrotic patient with focal glomerulosclerosis. The concentration of urinary protein increased almost in parallel with that of urinary glucose. This finding indicates that corticosteroids and/or furosemide can promote the disturbance of the tubular reabsorption mechanism together with increases in glomerular permeability and glomerular filtration rate.