Prazosin versus propranolol plus prazosin: a comparison in diuretic-treated hypertensive patients

The antihypertensive efficacy of prazosin was compared with that of a combination of prazosin and propranolol in 14 patients with essential hypertension. All patients had sitting diastolic blood pressures greater than or equal to 95 mm Hg despite daily therapy with 50 mg of hydrochlorothiazide and 240 mg of propranolol. After a 4-week monitoring period, patients were divided randomly into 2 groups in whom either (1) propranolol was reduced to 120 mg/day (to avoid potential hypotension) and prazosin was added, starting with an initial dose of 1 mg twice daily, or (2) propranolol was tapered and discontinued as prazosin was added. The average doses of prazosin were 7.4 and 7.6 mg/day, respectively. After 12 weeks of therapy, blood pressure was reduced in both groups, and there was no significant difference in the reduction of blood pressure or dose of prazosin in the 2 groups. Mean heart rate increased significantly in both groups (p less than 0.01), but more so in the group of patients who discontinued propranolol therapy. Thus, when a combination of 50 mg/day of hydrochlorothiazide and 240 mg/day of propranolol is insufficient to control hypertension, the addition of prazosin is shown to decrease blood pressure whether or not propranolol is continued.