A comparison of labetalol and prazosin combined with atenolol in non-responders to atenolol plus hydrochlorothiazide in uncomplicated hypertension.

After screening two local populations in the northern part of The Netherlands for hypertension, patients with a diastolic pressure (DP) between 95 and 120 mmHg were treated daily either with 50 mg hydrochlorothiazide or 100 mg atenolol. Nonresponders were given the combination and if necessary the dose of atenolol was increased to 200 mg. Non-responders to the latter combination were randomized and treated either with 50 mg hydrochlorothiazide and labetalol or with 50 mg hydrochlorothiazide, 200 mg atenolol and prazosin. If after 1 month a DP less than or equal to 90 mmHg had been reached the patient was reassessed after a further 3 months. If a DP greater than 90 mmHg was found the dose of labetalol or prazosin was increased and the patient was re-examined after 1 month. This protocol was followed until the maximum dose was reached or adverse reactions prevented a further increase in dosage. During 6 months of treatment there was a further drop in systolic and diastolic blood pressures under both regimens of, respectively, 8.6 and 2.4 mmHg for labetalol, and 7.7 and 5.0 mmHg for the prazosin group. At the end of the period the average daily doses of labetalol and prazosin were 1256 mg and 4.3 mg, respectively. There was no significant difference in the average number of complaints between the labetalol and the prazosin group.