Multicentre 12-week double-blind comparison of doxazosin, prazosin and placebo in patients with mild to moderate essential hypertension.

A 12-week double-blind study was performed to compare the safety and efficacy of doxazosin, prazosin and placebo in 172 patients with essential hypertension. According to response, patients received doxazosin 1-16 mg once daily, prazosin 0.5-10 mg twice daily, or placebo. Mean final daily doses were doxazosin 11.3 mg and prazosin 13.8 mg. Doxazosin once daily and prazosin twice daily both produced statistically significant reductions in both standing and supine blood pressures when compared with placebo. No significant differences between treatments were recorded for standing and supine heart rates. Doxazosin, prazosin and placebo all had a similar effect on plasma lipid profiles, i.e. an increase in HDL/total cholesterol of approximately 10%. The differences between treatments were not statistically significant. The HDL/total cholesterol ratio significantly increased from baseline to the end of treatment for all three groups, the decrease in triglycerides being statistically significant only in the doxazosin-treated group.