Angiotensin Converting Enzyme Inhibitors as Initial Monotherapy in Severe Hypertension: Quinapril and Captopril

Abstract

This 6-week, double-blind, parallel-group study compared the efficacy and safety of the angiotensin converting enzyme (ACE) inhibitors quinapril and captopril as initial monotherapies in patients with severe hypertension (diastolic blood pressure [DBP] greater than or equal to 115 and less than or equal to 130 mm Hg). A total of 97 patients, aged between 18 and 70 years, were randomized to 5 mg oral quinapril twice daily or 25 mg captopril twice daily with maximum titration to 20 mg quinapril twice daily or 100 mg captopril twice daily. With the morning dose 25 mg hydrochlorothiazide (HCTZ) could be added at week 4 of the double-blind phase or earlier if required for safety considerations. For the monotherapy phase, mean reductions in DBP of 12.1 mm Hg were achieved with both treatments. Clinical response rates (reduction in DBP greater than or equal to 10 mm Hg) were 58% for quinapril and 44% for captopril. At the end of therapy, with optional HCTZ, mean reductions in DBP were 19.0 mm Hg for the quinapril-treated group and 16.2 mm Hg for the captopril-treated group. None of the differences achieved statistical significance. Headache was the most frequently reported adverse event in both treatment groups with 8 reports each. No clinically significant changes in laboratory data were observed in any parameter for either treatment group. Quinapril and captopril provide comparable efficacy and safety in treatment of severe hypertension when used as initial monotherapy and with the addition of optional HCTZ.