An open, parallel group comparison of quinapril and captopril, when added to diuretic therapy, in the treatment of elderly patients with heart failure

This study aimed to compare the efficacy, tolerability and first-dose blood-pressure response of once-daily quinapril and twice-daily captopril when added to diuretic therapy in elderly patients with heart failure. The study was performed at a single centre as an open randomised parallel-group study, patients being selected for inclusion from the outpatient population. Following a starting dose of either 2.5 mg once-daily quinapril, or 6.25 mg twice-daily captopril, patients were reviewed at two-weekly intervals, and following clinical assessment a decision was made either to titrate up to the next medication stage or to enter the patient into the 16-week maintenance phase. Efficacy was assessed using a six-minute walking test, the New York Heart Association (NYHA) class, a functional lifescale (FLS) questionnaire and the cardiothoracic ratio (CTR)-at study entry and at the end of the maintenance phase. Blood pressure was measured for 5 h post-first-dose of medication. Sixty-one patients were randomised to treatment: 30 to quinapril and 31 to captopril. Following withdrawals, data from 36 patients (20 on quinapril, 16 on captopril) were available for analysis. The distance walked during the six-minute walking test improved in both groups; the difference between the treatment groups was not statistically significant. There were no significant changes in the FLS or CTR. An analysis of change in the NYHA status from study entry to study end showed a statistically significant difference between the two groups (p = 0.02) in favour of quinapril. Five patients in each group experienced hypotension during the 5 h following the first dose of medication. This study has shown heart failure to be as well controlled by once-daily quinapril as by twice-daily captopril, with comparable effects on first-dose blood-pressure response.