OBJECTIVETo evaluate the efficacy and tolerability of the fixed combination of amlodipine 5 mg/benazepril 10 mg once-daily therapy, compared with benazepril, 10 mg, monotherapy in patients with mild and moderate hypertension, and to evaluate the 24 h antihypertensive efficacy and the duration of action by ambulatory blood pressure monitoring.

METHODSIn a multicenter, randomized, double-blind, parallel controlled trial, 356 cases of hypertensive patients after 2 weeks wash-out, and then given 4 weeks of benazepril 10 mg monotherapy, 220 patients with mean seated diastolic blood pressure (SeDBP) remained ≥ 90 mm Hg (1 mm Hg = 0.133 kPa) were randomly divided into benazepril 10 mg/amlodipine 5 mg (BZ10/AML5) fixed-dose combination therapy group (once a day, n = 113), and benazepril monotherapy group (daily 20 mg, n = 107). In the two groups the patients with SeDBP ≥ 90 mm Hg were doubled the dosage of the initial regimen at the end of 4-week treatment for additional 4 weeks, and the patients with SeDBP < 90 mm Hg remained the initial regimen for additional 4 weeks. The primary endpoint was to evaluate the improvement of SeDBP at the end of 8-week treatment. There were 74 patients (the combination therapy group n = 38, monotherapy therapy group n = 36) completed the 24 h ambulatory blood pressure monitoring which was included in the final efficacy analysis.

RESULTSThe randomized, double-blind treatment for 8 weeks, the mean value of SeDBP reduction, the reaching target blood pressure rate and total successful response rate to the treatment (a SeDBP < 90 mm Hg or a decrease of 10 mm Hg or more from baseline) were (11.7 ± 6.8) mm Hg, 65.7% and 88.5% in the combination therapy group, respectively, and were (7.7 ± 6.9) mm Hg, 35.5% and 65.5% in the monotherapy group, respectively. There were statistically significant difference between the combination therapy and the monotherapy groups in all the 3 indexs (P < 0.001). The fixed combination significantly reduced systolic blood pressure (SBP) and diastolic blood pressure (DBP) values throughout the 24 h. The trough to peak ratios of DBP/SBP in the fixed compound of benazepril/amlodipine (10 mg/5 mg) and benazepril (20 mg) alone were 83.1%/76.0% and 85.8%/79.5%, respectively. Adverse events rates were 16.8% in the combination therapy group and 35.5% in the monotherapy group (P < 0.001).

CONCLUSIONSThe combination therapy with benazepril/amlodipine was superior to benazepril monotherapy and was well tolerated in patients with essential hypertension and allowing a satisfactory BP control for 24 hours.