Long-term benefit of cardioselective beta blockade with once-daily atenolol therapy in angina pectoris.
The long-term efficacy of once-daily atenolol cardioselective beta-blockade therapy for chronic stable angina pectoris was studied in nine coronary disease patients. After a placebo-controlled single-blind dose-ranging trial with 2-week drug periods of 25, 50, 100, and 200 mg, they continued on 100 or 200 mg daily for 1 year. Treadmill exercise test (ET) were performed at times at peak and trough serum atenolol concentrations and 24-hour ECG ambulatory recordings were obtained after placebo, after 2 weeks of 100 and 200 mg atenolol, and after 2 weeks of 100 and 200 mg atenolol, and after 3, 6, 9, and 12 months of 100 or 200 mg atenolol. During early and chronic atenolol therapy, angina frequency and nitroglycerin consumption were decreased (p less than 0.01 to less than 0.001). Twenty-four hour ECG and ET showed sustained heart rate suppression. Exercise duration until angina onset was prolonged during all periods of atenolol administration. Maximal improvement in exercise tolerance and angina relief was not reached until 3 months of atenolol therapy despite stable serum drug concentrations. During the 14 months fatigue occurred in three patients which was dose-limiting in only one. Thus atenolol 100 or 200 mg given once daily, proved well-tolerated and potent anti-ischemic myocardial actions which were effectively maintained during chronic therapy of angina pectoris.