A DOUBLE-BLIND COMPARISON OF ONCE-DAILY METOPROLOL CONTROLLED-RELEASEAND ATENOLOL IN THE TREATMENT OF CHINESE PATIENTS WITH MILD-TO-MODERATE HYPERTENSION

The efficacy and tolerability of controlled-release metoprolol (metopr olol CR/ZOK), 100-200 mg, and atenolol, 50-100 mg, once daily was comp ared in Chinese patients with mild to moderate essential hypertension. The study was of a randomized, double-blind, two-way crossover design . The active treatment periods lasted 4 weeks each and were preceded b y a 4-week placebo run-in period. The two double-blind phases were sep arated by a 2-week washout period on placebo. Blood pressures and hear t rates were measured at rest in each 2-week visit and during exercise at the end of each treatment period. Twenty-four patients (M/F = 14/1 0) were valid for efficacy analysis. Their ages ranged from 39 to 68, with a mean of 53.5 years. The rest supine blood pressure and heart ra te before active treatment was 160 +/- 15/106 +/- 6 mmHg and 75 +/- 14 beats/min (mean +/- SD), respectively. A responder was defined as exh ibiting a supine diastolic blood pressure less than or equal to 90 mmH g or a supine diastolic blood pressure reduction of at least 10% of th e baseline level. Both agents had high response rate: 88% and 92% of a ll patients responded to metoprolol CR/ZOK and atenolol, respectively. Both active treatments considerably reduced resting systolic and dias tolic blood pressures and heart rates as compared with baseline (p < 0 .001), respectively. With controlled-release metoprolol, a more pronou nced beta(1) blockade was obtained than with atenolol, which was expre ssed as a significant reduction in exercise induced heart rate at the highest comparable workload compared with placebo (p < 0.05). These fi ndings are compatible with those reported from western populations.