Background: Benazepril hydrochloride is a non-sulfhydryl-containing, angiotensin-converting enzyme (ACE) inhibitor. The short-term and long-term antihypertensive effects of benazepril remain to be established in Chinese.
Methods: Hypertensive subjects with diastolic blood pressure 95-110 mmHg, after two week placebo run-in first, entered a four-week double-blind phase with treatment of benazepril 10 mg once daily or captopril 25 mg three times daily, then received one-year open treatment of benazepril 10 mg daily with or without diuretics. Ambulatory blood pressure monitoring was performed at the end of placebo run-in, after four-week double-blind phase, and after one-year open treatment.
Results: Of the 75 subjects (41 male, 34 female, mean age 57 +/- 12 years, range 34-88 years) who completed the double-blind phase, 42 subjects finished the one-year extension phase. Reasons for withdrawal from the study included irritable cough (16, 21%), hypotension (1, 1%), and poor compliance (16, 21%). During the short-term double-blind phase, benazepril reduced clinic and mean 24-h ambulatory blood pressure by -21/-10 mmHg and by -17/-10 mmHg respectively, and captopril by -21/-13 mmHg and by -17/-10 mmHg respectively. After one-year open treatment by benazepril for the 42 subjects, the one-year average clinic blood pressure was 134/88 mmHg (155/104 mmHg at entry and 135/93 mmHg at the end of the double-blind phase), and the mean 24-h ambulatory blood pressure was 137/87 mmHg (149/95 mmHg at entry and 132/84 mmHg at the end of the double-blind phase).
Conclusions: The antihypertensive effect of benazepril 10 mg daily with or without diuretics is not significantly different from that of captopril 75 mg daily in the short-term and can reasonably be maintained for one year.