Assessment of Metoprolol, a Cardioselectíve Beta-Blocking Agent, during Chronic Therapy in Patients with Angina Pectoris

Ten patients wit ft typical angina pectoris and without hypertension, congestive heart failure or other disease were treated with alternating four-week courses of metoprolol (a ßi cardioselectíve beta-blocking agent), propranolol and placebo. Midway through each four-week period, drug dosage was doubled: thus, regimes were metoprolol, 150 and 300 mg/day, propranolol, 120 and 240 mg per day and placebo, 3 and 6 tablets per day. Serum concentrations of metoprolol Increased with increasing dosage in a proportion very similar to that seen with propranolol. Statistically significant reductions in angina frequencyjnitroglycerin consumption, and statistically significant increa.ses in total work performed on a bicycle ergometer, were found with both active compounds when compared with placebo. No significant dififerences were noted between the two active compounds. Though most patients showed greatest improvement on the higher of the two drug dosages, three patients with metoprolol and two with propranolo