Antiproteinuric effects of enalapril and losartan: a pilot study

In this randomized double-blind crossover trial we compared the antiproteinuric effects of enalapril and losartan in six children with proteinuria and underlying renal injury. The primary endpoint was reduction in proteinuria during therapy. The study had two 8-week on-drug arms, with a 4-week washout period between. Baseline proteinuria was similar, enalapril 87 mg/m² per hour and losartan 77 mg/m² per hour. The mean reduction in proteinuria with enalapril was 48% (37%–57%) with a standard error of the mean of 3%; with losartan it was 31% (14%–52%) with a standard error of the mean of 7%. Although there was a significant reduction in proteinuria with the use of both drugs, the difference in reduction of proteinuria, 48% versus 31%, was not considered clinically significant. Potassium remained below 4.5 mmol/l in all patients. No patient's creatinine rose more than the standard deviation of our assay. Blood pressure (BP) control was acceptable in four of the six patients; two patients had persistently elevated or increased BP on each drug. Side effects were minimal; none requiring withdrawal, one requiring dose reduction. Studies have shown that angiotensin converting enzyme inhibitors can reduce proteinuria in children with renal disorders. No studies to date have examined the reduction of proteinuria achieved by angiotensin receptor blockers. Our study, although small, suggests that angiotensin receptor blockers may reduce proteinuria as effectively, and as safely, as angiotensin converting enzyme inhibitors.Editorial comment Despite its limitations, this pilot study highlights the need for and may stimulate a double-blind prospective trial to compare the antiproteinuric effects of angiotensin blockers and angiotensin converting enzyme inhibitors in children.