A multicenter double-blind study of the efficacy and safety of once and twice daily dilevalol compared to propranolol.

Dilevalol, the R,R isomer of labetalol, is a non-selective beta-adrenergic blocking drug with vasodilator properties which differ from those of labetalol in that they are attributable to beta-2 agonism rather than alpha-1 blockade. This multicenter, double-blind, randomized study compares the antihypertensive efficacy and safety of dilevalol with propranolol and, in addition, compares the efficacy of dilevalol when given once daily with twice daily. Caucasian patients with mild and moderate essential uncomplicated hypertension were divided into three treatment groups and received either propranolol twice daily (N = 59), dilevalol twice daily (N = 60), or dilevalol once daily (N = 53). Patients were given increasing doses of these medications over a 2 to 10 week period to achieve a supine diastolic blood pressure (SuDBP) of less than 90 mm Hg. The three regimens were equally effective in lowering supine blood pressure (dilevalol daily and twice daily reduced SuDBP by 14 Hg and propranolol by 13 mm Hg). Patients with at least a 5 mm Hg reduction in SuDBP then entered a two month maintenance phase. Dilevalol, whether given once (N = 40) or twice daily (N = 55) maintained the supine systolic blood pressure more effectively (dilevalol daily--15 mm Hg, twice daily--13 mm Hg, P less than .05) than propranolol (N = 53, 11 mm Hg) and dilevalol given once daily maintained diastolic blood pressure more effectively than propranolol (17 mm Hg v 14 mm Hg, P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Multicenter comparison of dilevalol to placebo in patients with mild hypertension.

The antihypertensive effects of oral dilevalol, a beta-blocking agent with vasodialating properties were compared with placebo in 128 mildly hypertensive patients (supine diastolic blood pressure 95 to 105 mm Hg) in a multicenter, double-blind, parallel group study. Following a 4-week placebo phase, 63 patients were randomly assigned to receive dilevalol and 65 to receive placebo. A titration phase followed during which the dose of dilevalol was increased every other week from 100 mg to 800 mg to achieve a supine diastolic blood pressure (SDBP) less than 90 mm Hg and decreased by 10 mm Hg or more from baseline. A matching number of placebo capsules for each dose level of dilevalol was dispensed for blinding purposes. Patients who had at least a 5 mm Hg reduction in SDBP entered a 1-month maintenance phase. Blood pressure and heart rate were measured weekly 20 to 24 hours after a dose. This study demonstrated that the minimally effective dose of dilevalol was 100 mg, which was shown to result in a significantly (P less than or equal to 0.05) greater reduction in systolic BP. A once-daily dose of 200 mg was superior to placebo in both systolic and diastolic BP effects (P less than 0.001 and less than 0.001, respectively), and this superiority was seen again at both the end of titration and the end of the study. The BP reduction was accompanied by a small (5 bpm) decrease in heart rate. The side effect profile of dilevalol was not different from placebo. Dilevalol appears to have no adverse effect on plasma lipids.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of labetalol and prazosin in hypertensive patients using automated ambulatory monitoring.

The differential effects of prazosin and labetalol on blood pressure and heart rate in the clinic and during daily activity were measured in a double-blind study utilizing automatic ambulatory monitors. One hundred five patients with essential hypertension (sitting diastolic blood pressure equal to 101 mm Hg) were randomly assigned to receive prazosin (n = 52) or labetalol (n = 53). Sixty-eight percent of labetalol-treated patients and 50 percent of prazosin-treated patients achieved blood pressure control during clinic visits (sitting diastolic blood pressure less than 90 mm Hg) and were subsequently monitored for 12 hours of normal daily activities. Ambulatory monitoring revealed labetalol-treated patients to have significantly greater decreases in systolic and diastolic blood pressures during daily activity than prazosin-treated patients. Heart rate and rate-pressure product were significantly reduced in the labetalol group but not in the prazosin group. It is concluded that the potential benefits of dual adrenergic blockade, not readily apparent in the non-stressful clinic environment, become more evident during the course of daily activities.