Comparison of the duration of action of atenolol and nadolol for treatment of angina pectoris

In a randomized, double-blind, placebo-controlled cross-over study, 16 patients with angina on effort due to proven coronary artery disease were given atenolol 50 or 100 mg and nadolol 40 or 80 mg every morning. Compared with placebo control, both β blockers equally decreased angina frequency, suppressed supine, standing, submaximum and maximum heart rates and double products (all p < 0.0001) and increased exercise tolerance (p < 0.01) when the exercise stress test was done 3 to 4 hours after the daily dose. When the exercise stress test was done 24 hours after the daily dose, the suppression of resting and maximum exercise heart rates and maximum double product was more pronounced by nadolol than atenolol (p < 0.05). Ambulatory electrocardiography heart rates were also equally suppressed by both β blockers in the afternoon, evening and nighttime hours. However, in the hours just before and just after the ingestion of the daily dose the effect of nadolol (elimination half-life 1,436 ± 420 minutes) was more pronounced (p < 0.05) than that of atenolol (half-life 537 ± 62 minutes). Negative correlations (p < 0.03) between β-blocker blood levels and submaximal exercise heart rates and double products were observed.