Effect of prednisone on renal function in man

To clarify the rise in plasma creatinine concentration previously observed during prednisone treatment, we studied changes in renal function in Graves' ophthalmopathy patients before and after 2 weeks of either prednisone 60 mg/day or retrobulbar radiotherapy (controls). Compared to retrobulbar radiotherapy, prednisone treatment was associated with an increase in: (a) plasma creatinine concentration (from 68 +/- 4 to 76 +/- 4 mumol/l), (b) glomerular filtration rate (GFR, from 93 +/- 4 to 102 +/- 5 ml/min/1.73 m2), and (c) urinary creatinine excretion rate (from 510 +/- 40 to 570 +/- 40 mumol/h). We conclude that GFR rises during 2 weeks of high-dose prednisone administration, a rise that is not reflected by a decrease in plasma creatine concentration. On the contrary, both plasma creatinine concentration and urinary creatinine excretion increase, probably as a result of the catabolic effect of prednisone. As established by the present study, prednisone 60 mg/day is associated with protein wasting, also after 14 days of treatment