Comparison of the efficacy of atenolol and its combination with slow-release nifedipine in chronic stable angina.

There is still uncertainty of whether combined therapy with a beta-blocker and calcium-channel antagonist provides additive or synergistic clinical benefits in most patients with stable angina pectoris. The comparative antianginal effect of atenolol 50 mg and atenolol 50 mg and slow release nifedipine (20 mg) twice a day was assessed in 27 patients with chronic stable angina in a randomized, double-blind, crossover study. After a 4 week run-in period on atenolol, patients were randomly allocated to receive either atenolol alone or its combination with nifedipine and then crossed over to the alternative treatment for a further 4 weeks. Symptom-limited exercise treadmill tests were performed according to the Naughton protocol. The major endpoints in this study were (a) exercise time to pain; (b) exercise time to > or = 1 mm ST depression; (c) total exercise time; (d) maximal ST-segment depression; (e) number of anginal attacks; and (f) nitrate consumption. The preexercise systolic blood pressure was lower on the combination treatment than on atenolol alone, but heart rate was lower on atenolol compared with the combination treatment. There was no difference in the systolic blood pressure at the onset of pain or at 1 mm ST depression, while heart rate was lower on both occasions with atenolol compared to the combination treatment. There was no difference between the two treatments in terms of the rate-pressure product at the onset of pain or at 1 mm ST depression. Twice as many patients experienced pain later with the combination treatment than with atenolol alone.(ABSTRACT TRUNCATED AT 250 WORDS)