A 24-week multicenter double-blind study of doxazosin and hydrochlorothiazide in patients with mild to moderate essential hypertension.

The new alpha1-adrenoceptor antagonist, doxazosin (DOX), was compared with hydrochlorothiazide (HCTZ), both drugs administered once daily, in a randomized double-blind study including 115 patients. The mean final daily doses used were DOX, 10.8 mg; HCTZ, 89.1 mg. There were no statistically significant differences between treatment groups for blood pressure (BP) changes except that HCTZ produced a significantly greater fall (p = 0.04) in supine systolic BP than DOX. The statistically significant mean differences in changes in lipid parameters (total cholesterol and total triglycerides) were in favour of DOX. The number of patients reporting side-effects were DOX, 27/57; HCTZ, 29/53, with two DOX- and five HCTZ-treated patients withdrawn due to side-effects. In the HCTZ-treated group, laboratory serum tests indicated 11 patients with abnormally low potassium and seven with abnormally high uric acid concentrations. The overall results suggest a benefit-to-risk ratio in favour of DOX.