Initial effect of enalapril on kidney function in patients with moderate to severe chronic nephropathy.

Angiotensin converting enzyme (ACE) inhibitors has been suggested to halt the progression of chronic renal failure. As the initial step of a controlled trial of this hypothesis, it was investigated whether start of enalapril in patients with severe chronic nephropathy might cause a critical fall in their renal function. Thirty-one patients were studied, 26 on chronic antihypertensive treatment with drugs other than ACE inhibitors and 5 untreated normotensive. 51Cr-EDTA plasma clearance and renal technetium-99m dimercaptosuccinic acid (99mTc-DMSA) scintigraphy were made before and 24 h after start of enalapril, mean dose 9 mg. Blood pressure fell from median 148/88 to 119/78 mmHg (p less than 0.01). Glomerular filtration rate (GFR) fell from median 14 to 12 ml/min/1.73 m2 (p less than 0.01). The median change in GFR was -14% (range -44% to +10%). The split renal function was unchanged and the scintigrams showed no intrarenal activity defects. In conclusion, enalapril caused a fall in GFR, which was clinically acceptable in most of the patients.