An open one-year comparison of doxazosin and prazosin for mild to moderate essential hypertension.

The long-term safety, efficacy and effect on serum lipid profile of doxazosin, a new alpha 1-adrenoceptor inhibitor administered once daily, were compared with those of prazosin, administered twice daily, in 104 patients with essential hypertension treated for 1 year. Doxazosin produced clinically significant decreases in standing and supine blood pressures over a period of 1 year. These decreases were similar to those produced after an initial period of 12 weeks of double-blind therapy. The reductions in blood pressure produced by doxazosin were greater than those produced by prazosin. Minor and clinically nonsignificant changes in heart rate were observed with both drugs. The favorable changes from baseline in plasma lipid concentrations observed after 12 weeks of double-blind therapy were maintained throughout the 1-year open study. These were average increases in the mean high density lipoprotein cholesterol concentration and the derived high density lipoprotein/total cholesterol ratio, and average decreases in total cholesterol and total triglyceride concentrations. The incidence of side effects reported was similar for doxazosin and prazosin. Most were rated as being mild or moderate in severity and were tolerated or disappeared with continued therapy. Results of laboratory tests, electrocardiograms, ophthalmoscopy and body weight measurements revealed only minor changes from baseline, and none was judged to be of clinical significance. These findings demonstrate that doxazosin is a safe and effective antihypertensive agent suitable for once-daily dosing, and has favorable effects on the serum lipid profile.