Safety and efficacy of once-daily carvedilol vs twice-daily labetalol in mild to moderate hypertension
A multicenter, randomized, double-blind, parallel-group trial of 8 weeks' duration was designed to compare the efficacy and safety of once-daily carvedilol with that of twice-daily labetalol in patients with essential hypertension. A total of 61 patients (13 women and 48 men) aged 26–64 years (mean ± SEM = 49.6 ± 1.3 years) were enrolled. All patients had mild to moderate hypertension, defined as diastolic blood pressure (DBP) of 95–114 mmHg at the end of a 1- to 2-week single-blind placebo period. In all, 30 patients received carvedilol (25 mg once daily) and 31 received labetalol (200 mg twice daily). The initial dose could be doubled for both treatment groups at day 29 if the DBP was > 90 mm Hg on days 28 and 29. Hemodynamic parameters, including supine and standing DBP, systolic blood pressure (SBP), and heart rate (HR), were measured and safety was evaluated at baseline and at days 14, 28, and 56 at the end of the dosing interval. In all, 3 patients on carvedilol and 4 patients on labetalol required upward dose titration after 1 month. At the end of the trial, 26 of 30 carvedilol-treated patients and 27 of 31 labetalol-treated patiens (87% of each group) had a supine DBP of ⩽ 90 mm Hg. On day 56, mean decreases in supine DBP, SBP, and HR in the carvedilol group were 18.5 and 23.4 mmHg and 11 beats/min, respectively, from baseline values of 101.6 and 163.8 mmHg and 80 beats/min, respectively. Corresponding values for the labetalol group were 17.7 and 25.9 mmHg and 12 beats/min from baseline values of 101.2 and 165.8 mmHg and 79 beats/min. Decreases in all hemodynamic parameters were also measured after days 14 and 29 in both treatment groups. There were no significant differences between treatment groups at any time point. The safety profiles of both drugs were good. No severe adverse events were reported and no patient withdrew due to adverse events. In conclusion, the safety and efficacy of once-daily carvedilol (25 or 50 mg) were comparable with those of twice-daily labetalol (200 or 400 mg) in patients with mild to moderate essential hypertension.