Medical treatment of myocardial ischemia in coronary artery disease: effect of drug regime and irregular dosing in the CAPE II trial.

OBJECTIVES: The Circadian Anti-ischemia Program in Europe (CAPE II) compared the efficacy of amlodipine and diltiazem (Adizem XL) and the combination of amlodipine/atenolol and diltiazem (Adizem XL)/isosorbide 5-mononitrate on exercise and ambulatory myocardial ischemia during regular therapy and after omission of medication. BACKGROUND: The optimal medical therapy for ischemia suppression and the impact of irregular dosing using agents with different pharmacologic properties has not been established in patients with coronary disease. METHODS: Patients with > or = 4 ischemic episodes or > or = 20 min of ST segment depression on 72-h electrocardiogram were randomized to amlodipine 10 mg once daily or diltiazem (Adizem XL) 300 mg once daily in a 14-week double-blind randomized multicountry study. In the second phase, atenolol 100 mg was added to amlodipine and isosorbide 5-mononitrate 100 mg to diltiazem (Adizem XL). Ambulatory monitoring (72 h) and exercise testing were repeated after both phases, on treatment and after a 24-h drug-free interval. RESULTS: Both monotherapy with amlodipine and diltiazem (Adizem XL) were effective on symptoms and ambulatory and exercise ischemia. Combination therapy reduced ischemia further, with amlodipine/atenolol superior to diltiazem (Adizem XL)/isosorbide 5-mononitrate. Amlodipine/atenolol was significantly superior during the drug-free interval with maintenance of ischemia reduction. CONCLUSIONS: Amlodipine, with its intrinsically long half-life alone or together with beta-blocker, is likely to produce superior ischemia reduction in clinical practice when patients frequently forget to take medication or dose irregularly.