FIRST-DOSE EFFECTS OF ENALAPRIL 2.5 MG AND CAPTOPRIL 6.25 MG IN PATIENTS WITH HEART-FAILURE - A DOUBLE-BLIND, RANDOMIZED, MULTICENTER STUDY

Significant decreases in blood pressure (BP) may occur when administra tion of angiotensin-converting enzyme (ACE) inhibitors is initiated fo r the treatment of heart failure. The purpose of this study was to com pare the safety and tolerability of recommended initial doses of the l onger-acting ACE inhibitor enalapril (ENAL) with those of the shorter- acting captopril (CAP) in patients with heart failure who were treated concomitantly with digitalis and diuretic agents. We evaluated BP, se rum ACE activity, and clinical status when a low, first dose of ENAL ( 2.5 mg, n = 59) or CAP (6.25 mg, n = 58) was administered in a double- bind, randomized, and parallel fashion to 117 patients with mild to mo derate heart failure. BP and serum ACE activity were measured at 30 mi n and hourly for 8 hours after drug administration. BP decreases were similar for both groups (mean supine BP -6.2/-4.8 mm Hg for ENAL vs -8 .3/-6.4 mm Hg for CAP; mean standing BP -9.2/-5.6 mm Hg for ENAL vs -1 0.0/-4.7 mm Hg for CAP). Although the maximum mean decrease in BP occu rred at hours 4 and 5 in the ENAL group and hours 1 and 2 in the CAP g roup, considerable between-group overlap was observed for individual p atients. Decreases in mean serum ACE activity occurred earlier and wer e of shorter duration in the CAP group, ENAL significantly inhibited s erum ACE activity to a greater extent than did CAP at all time points except the Ist hour. Administration of a first dose of ENAL, 2.5 mg or CAP, 6.25 mg to patients with heart failure was well tolerated.