Acute hemodynamic and hormonal effects of ramipril in chronic congestive heart failure and comparison with captopril.

Acute hemodynamic and hormonal responses to ramipril in comparison with captopril were studied in 10 patients with moderate to severe congestive heart failure in an open, randomized study. Both drugs were given to 5 patients each in 2 increasing doses on 2 successive days. After 5 mg of ramipril angiotensin converting enzyme (ACE) activity was significantly decreased during 24 hours with a maximum decrease 4 hours after administration. Mean arterial blood pressure decreased from 84 +/- 5 to 62 +/- 5 mm Hg at 4 hours and 71 +/- 4 mm Hg at 12 hours, respectively, after this dose. Capillary wedge pressure decreased from 19 +/- 1 mm Hg to 13 +/- 1 mm Hg at 4 hours with a maximum increase in cardiac output from 3.8 +/- 0.3 liters/min to 4.4 +/- 0.3 liters/min at 2 hours. No significant cardiac effects were present 8 hours after administration. After 10 mg of ramipril, cardiac and hormonal effects showed a quicker onset of action and longer duration compared with the 5 mg dose. Mean arterial pressure decreased to 61 +/- 6 mm Hg. Similar effects were seen after captopril, but with a significantly shorter duration. Mean arterial pressure decreased from 82 +/- 4 mm Hg to 64 +/- 5 mm Hg after 12.5 mg and to 58 +/- 6 mm Hg after 25 mg of captopril. In patients with congestive heart failure ramipril has the hemodynamic profile of a long-acting and potent ACE inhibitor. Significant cardiac effects are present during 4 to 8 hours and ACE activity is still significantly inhibited 24 hours after a single dose of ramipril.(ABSTRACT TRUNCATED AT 250 WORDS)