Additive antiproteinuric effect of the NSAID indomethacin and the ACE inhibitor lisinopril.

Both angiotensin-converting enzyme (ACE) inhibitors like lisinopril and nonsteroidal anti-inflammatory drugs (NSAIDs) like indomethacin have been shown to lower urinary protein excretion in renal disease. If this effect is caused by different mechanisms of action, the combination of these agents could have an additive antiproteinuric effect. We studied the effects of lisinopril and indomethacin separately and in combination in 10 patients with the nephrotic syndrome. Proteinuria was lowered from 10.5 +/- 1.8 g/24 h in the control period to 4.5 +/- 1.1 g/24 h on indomethacin, 4.3 +/- 1.0 g/24 h on lisinopril and to 2.4 +/- 0.8 g/24 h on the combination. Glomerular filtration rate (GFR) fell on either monotherapy, but particularly on the combination of drugs. The renal hemodynamic changes suggested a preglomerular vasoconstriction by indomethacin and a postglomerular vasodilation by lisinopril. Severe hyperkalemia occurred in 3 patients on the combination therapy. We conclude that the combination of indomethacin and lisinopril has an additive antiproteinuric effect. This, as well as the more pronounced fall in GFR on the combination, may suggest that both drugs lower proteinuria by decreasing intraglomerular capillary pressure but via different mechanisms. Combining these drugs may be useful in the symptomatic treatment of nephrotic syndrome, but renal function and serum potassium should be monitored carefully.