Double-blind comparison of urapidil and prazosin in the treatment of patients with essential hypertension.

A multicentre double-blind comparative study of urapidil and prazosin was performed in 412 outpatients with mild to moderate essential hypertension. 222 patients were treated by monotherapy (107 on urapidil and 115 on prazosin), and 190 in combination with thiazide diuretics (99 on urapidil and 91 on prazosin). After a 4-week control period on placebo, the patients were randomised for treatment with twice daily urapidil (total of 30-120 mg/day) or 3 times daily prazosin (total of 1.5 to 6 mg/day) for 12 weeks. The results indicated that: (1) In monotherapy, blood pressure decreased significantly in both treatment groups 2 weeks after the start of treatment, and a further decrease in blood pressure was observed in both groups thereafter. The rates of responders (final mean blood pressure reductions of 13 mm Hg or more) were similar: 64.1% in the urapidil group and 64.0% in the prazosin group. Heart rate did not change in the 2 groups at any stage. Side effects were observed in 15.9% of the patients in the urapidil group and in 11.3% of the prazosin group (NS). When an overall utility rate was determined on the basis of antihypertensive effect, side effects and laboratory findings, the treatment was judged 'useful or better' in 58.9% of the patients in the urapidil group and 60.2% of the prazosin group. The difference was again not significant. (2) In combination therapy, a significant decrease in blood pressure was also observed 2 weeks after the start of treatment. The responder rates were 66.7% in the urapidil group and 65.0% in the prazosin group (NS).(ABSTRACT TRUNCATED AT 250 WORDS)