COMPARISON OF THE EFFICACY OF ENALAPRIL P LUS HYDROCHLOROTHIAZIDE ANDCAPTOPRIL PLUS HYDROCHLOROTHIAZIDE COMBINATIONS ON MILD-TO-MODERATE HYPERTENSION BY AMBULANT BLOOD-PRESSURE MONITORING

This two-centre trial compared the efficacy of combinations of enalapr il + hydrochlorothiazide (E + H) and captopril + hydrochlorothiazide ( C + H) on mild-to-moderate hypertension, after a two-week placebo peri od, in 26 patients with mild-to-moderate HT (DBP between 95 and 114 mm Hg) not controlled by,previous treatment, randomized under double-blin d conditions into two groups for two 4-week crossover treatment period s separated by a 4-week wash-out period. One group received E + H (20 mg/12.5 mg) followed by C + H (50 mg/25 mg) and the other group receiv ed C + H (50/25) followed E + H (20/12.5), once a day. The efficacy of the two treatments was evaluated by 24-hour ambulatory blood pressure monitoring (ABPM) at the start of the study and after each treatment period. Plasma renin activity, aldosterone and angiotensin converting enzyme were assayed under the same conditions. Analysis was based on 2 6 cases, as none of the patients (were withdrawn from the trial. No di fference was observed between the two groups in terms of the main biom etric and laboratory characteristics. Blood pressure evaluated by ABPM and intermittently was not significantly different between the two gr oups at the time of inclusion in the study. On intermittent Bp determi nations, E + H and C + H decreased diastolic and systolic blood pressu re, with no significant difference between the two treatments. On ABPM , the two treatments significantly decreased mean systolic, diastolic and mean blood pressure during the diurnal, nocturnal and circadian pe riods. During these three periods, the reduction of blood pressure was more marked with E + H than with C + H (24-hour period: 9.2 versus 4. 4 mmHg for DBP, 14.8 versus 8.2 mmHg for SBP, 12 versus 6.6 mmHg for M BP, p<0.01 for the three measurements). The treatments did not modify the plasma aldosterone level, but significantly increased plasma renin activity, with a more marked action for E + H (p < 0.01). The angiote nsin converting enzyme level was not modified by C + H, but was signif icantly decrased by E + H (p < 0.01). Clinical adverse effects were ra re (4 with C + H, 1 with E + H) and minor. One patient in each group d eveloped a significant reduction of serum potassium, but the other lab oratory parameters (creatinine, glucose, uric acid, sodium) remained s table. This study, based on the use of ABPM, shows that the combinatio n of enalapril + hydrochlorothiazide exerts a superior antihypertensiv e activity to that of captopril + hydrochlorothiazide, E + H decreased the serum angiotensin converting enzyme level, in contrast with C + H . The adverse effects of these two drugs were rare and minor.