Effect ofcaptopril onrenal function inpatients with congestive heart failure

SUMMARY Angiotensin converting enzymeinhibitors canimprove haemodynamics inpatients with congestive heart failure andmay enhance sodium excretion inhypertensive patients. Inametabolic unit we assessed theeffects ofoneofthese agents onrenal function innine patients withstable New YorkHeart Association functional class 3or4congestive heart failure. Single blinded, thepatients received placebo forthree days, 25to100mg ofcaptopril three times adayforthree days, andthree more daysofplacebo. Meanblood pressuredecreased during captopril, withlittle change inheart rateorrespiration. Serumureawas slightly higher during captopril administration. Themean change increatinine clearance during captopril wasinsignificant, butitdecreased more than 25%in three ofnine patients. Decreases increatinine clearance correlated withlower blood pressureduring captopril andweremostobvious inpatients withhighbaseline plasma renin activity. Urine output andbothsodium andpotassium excretion decreased during captopril. Thuscaptopril failed to improve natriuresis inpatients withcongestive heart failure andclose monitoring ofkidney function isnecessarywhenusing this agentinpatients withcongestive heart failure, particularly whenblood pressurefalls tolower levels.