A comparison of doxazosin and enalapril in the treatment of mild and moderate essential hypertension

Abstract

The antihypertensive efficacy and safety of doxazosin, a selective α 1-adrenoceptor antagonist, were compared with that of the angiotensin-converting enzyme inhibitor enalapril in an 18-week double-blind, parallel-group trial. Sixty-seven hypertensive patients entered the three-phase study, which involved a 4-week placebo washout period, a 10-week titration period with doxazosin, 1 to 16 mg, or enalapril, 10 to 40 mg once daily followed by a 4-week maintenance period. The target response was a standing diastolic blood pressure ≤90 mm Hg. In the 62 efficacy evaluable patients the mean final daily dose of doxazosin was 5.6 mg and 25.5 mg for enalapril. The percentages of therapeutic successes were 74% in the doxazosin- and 81% in the enalapril-treated groups; the proportions in whom standing diastolic blood pressure ≤90 mm Hg were 55% and 61%, respectively. Both sitting and standing blood pressures were significantly reduced at all visits during the 14-week treatment period in both groups. Twelve patients receiving doxazosin reported 14 adverse events and nine patients administered enalapril reported 19 adverse events; therapy was stopped in three patients in each group because of side effects. The overall assessment of efficacy was excellent or good for 71% of the doxazosin-treated and 67% of the enalapril-treated patients, respectively. Toleration of therapy was excellent or good for 91% of the doxazosin-treated and 88% of the enalapril-treated patients, raspectively. No clinically significant changes were observed in the serum lipids, plasma blochemistry, or hematologic profiles. The results of this study indicate that doxazosin and enalapril have comparable antihypertensive efficacy and possess similar primary prevention potential.