This double-blind, parallel-group study compared the effects of nebivolol, a novel cardioselective beta-blocker, with those of nifedipine sustained-release on 24-hour ambulatory blood pressure and plasma lipoprotein levels. After a washout period of 8 weeks, 51 patients with mild to moderate essential hypertension were randomized to double-blind treatment with either nebivolol 5 mg once a day (n = 26) or nifedipine sustained-release 20 mg bid (n = 25) over a period of 12 weeks. Both treatments produced similar and significant (P = .0001) reduction in office blood pressure as well as in 24-hour, work, awake, and sleep ambulatory blood pressure. The clinical response (diastolic blood pressure less than 90 mmHg or decreased by greater than or equal to 10 mmHg) rate was 69% for nebivolol and 59% for nifedipine, respectively. Moreover, the nebivolol and nifedipine treatment-induced decreases in mean 24-hour ambulatory blood pressure were similar to the decreases in clinic blood pressure. Furthermore, the percentages of "blood pressure loads" (awake greater than 140/90 mmHg and asleep greater than 120/80 mmHg) were lowered significantly (P = .0001), from 60% to 29% with nebivolol and from 60% to 39% with nifedipine. Mean ambulatory heart rate was reduced (P = .0001) from 79 +/- 7 to 68 +/- 7 beats/minute during nebivolol therapy and from 80 +/- 9 to 79 +/- 7 (not significant) with nifedipine. Total plasma cholesterol and low-density lipoprotein levels decreased significantly (P less than .05) by 5 and 8%, respectively, after nebivolol treatment, and each decreased by 3% after nifedipine treatment.(ABSTRACT TRUNCATED AT 250 WORDS)