Comparison of a fixed combination of nifedipine slow release and atenolol (Bay-R-1999) and nifedipine slow release alone in patients with stable angina pectoris: A multicenter, randomized, double-blind, parallel-group study

Abstract

This multicenter, randomized double-blind, parallel-group study was designed to compare the therapeutic effects of a fixed combination of atenolol 50 mg plus nifedipine slow release (SR) 20 mg twice daily (Bay-r-1999) with the effects of nifedipine SR 20 mg twice daily alone in mild to moderately symptomatic patients with stable angina pectoris. After a 2-week run-in period during which patients underwent two exercise tests and 48-hour ambulatory electrocardiographic monitoring, 72 male patients were randomized to two treatment groups. A total of 66 patients completed the study. After 4 weeks of active treatment, patients underwent a 12-hour postdosing exercise test and 48-hour ambulatory electrocardiographic monitoring. The rank analysis of variance did not show any significant between-group difference in time to 1-mm ST segment depression. ST segment depression ≥1 mm occurred in 20 of 32 patients receiving Bay-r-1999 and in 26 of 34 patients receiving nifedipine SR alone. In these patients, Bay-r-1999 increased the time to 1-mm ST segment depression from a baseline value of 400 ± 105 seconds to 519 ± 110 seconds (+30%; P < 0.0001) and nifedipine SR from 398 ± 108 seconds to 482 ± 130 seconds (+21%; P < 0.0001). The difference between the groups was not statistically significant. Similarly, no statistically significant intergroup differences were observed in relation to the effects of the two treatments on the frequency or duration of ambulatory electrocardiographic monitoring—detected ischemic episodes, the weekly frequency of anginal episodes, or nitroglycerin consumption. Unwanted side effects were reported less frequently in the fixed combination group than in the nifedipine grou (3% vs 19%, respectively), but these differences were not statistically significant. In conclusion, this study suggests that combined treatment with atenolol and nifedipine SR does not provide additional antianginal or anti-ischemic effects compared with monotherapy with stable angina pectoris. Adding atenolol to nifedipine SR may, however, results in a reduced frequency of unwanted side effects.