[The effect of enalapril and prazosin on mild to moderate hypertension in black South Africans].

A double-blind, placebo-controlled clinical trial with a parallel design was conducted on 35 black patients with mild to moderate hypertension. After a 4-week run-in on placebo, baseline values were recorded and only patients with diastolic pressures of 95 - 115 mmHg were admitted to the trial, which lasted 10 weeks. These patients were randomised in three groups, receiving daily initially either 5 mg enalapril, 2 mg prazosin or placebo. Blood pressures and heart rates were measured once every week and in poor responders dosages were increased on a 2-weekly basis. Enalapril was increased to 10, 20 and 40 mg during the last 4 weeks, and prazosin was respectively increased to 4, 10 and 20 mg. The only statistically significant difference between baseline and post-treatment values (week 10) was a reduction in heart rate in the prazosin group, but no differences in either systolic or diastolic pressure could be detected in this group or between any of the three measurements in the other two groups. When the mean values of 3 groups were compared on a weekly basis it transpired that there were no statistically significant differences between any of the baseline values but that the mean heart rate at week 2 and the mean diastolic pressure at week 9 in the prazosin group and the mean systolic pressures in the enalapril group at weeks 6, 8 and 10 were significantly lower than the corresponding placebo values. Cumulative sum techniques were used to measure the course of the effects of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)