Effects of indomethacin on the renal function and renin-aldosterone system in chronic glomerulonephritis

The effects of indomethacin on plasma renin activity (PRA), plasma and urine aldosterone levels and on renal function were studied in 37 patients with chronic glomerulonephritis (GN). Indomethacin produced a significant decrease in PRA, in plasma and urinary aldosterone levels and an increase in serum potassium levels. In 4 patients indomethacin induced the clinical syndrome of hyporeninemic hypoaldosteronism with hyperkalemia, which developed during the first weeks of treatment, persisted during treatment and disappeared without any additional drugs when indomethacin was stopped. In 14 patients with chronic GN, indomethacin caused a decrease in glomerular filtration rate (GRF). Their pretreatment PRA was significantly higher than that of patients with unchanged or increased GFR and most of them had prominent sclerotic changes on biopsy. Indomethacin considerably depressed diuresis and urinary sodium excretion. The antidiuretic and antinatriuretic effects of indomethacin were more pronounced in patients with the nephrotic syndrome. The results suggest that indomethacin exerts an effect on the renin-aldosterone axis, may be a cause of drug-induced hyporeninemic hypoaldosteronism and may cause a decrease in GFR in patients with high PRA.