Bisoprolol versus hydrochlorothiazide plus amiloride in essential hypertension, a randomized double-blind study.

Beta blocker monotherapy is often considered to be inadequate in essential hypertension. It was the aim of this study to compare the antihypertensive activity of the new betablocker bisoprolol with the diuretic combination: hydrochlorothiazide plus amiloride. Forty hypertensive patients (DBP 95-120 mmHg) were enrolled in the study, of which 34 were evaluable for efficacy. The patients were, under double-blind conditions, randomly allocated to receive 10 mg bisoprolol (B) or 50 mg hydrochlorothiazide plus 5 mg amiloride (HA) as single daily doses for 30 days. Patients whose DBP had been normalized (less than or equal to 90 mmHg) after 30 days (D 30) continued the monotherapy for another 30 days. Patients whose DBP remained over 90 mmHg were, under single-blind conditions, kept on their initial treatment but received in addition the alternative drug for another 30 days (D 60). Blood pressure measurements were performed 24 hours after drug intake. The two groups comprising 17 patients each were comparable with regard to the patients' characteristics and baseline blood pressure values. After 30 days of treatment supine SBP, DBP and HR were significantly more reduced with B than with HA. The mean reduction of DBP was 16.8 +/- 8.0 mmHg with B and 8.4 +/- 6.4 mmHg with HA (P less than 0.002). After 30 days of monotherapy, blood pressure was within the normal range in 15/17 (88.2%) patients treated with B but in only 4/17 (23.5%) patients treated with HA (B vs HA: P less than 0.001). In the B group, there was a further slight decrease in SBP, DBP and HR during the second 30 day period.(ABSTRACT TRUNCATED AT 250 WORDS)