Effect of betaxolol on heart rate at rest and during exercise.

Betaxolol, a new beta-receptor blocking drug administered as a single dosage of 40 mg given orally, causes a maximal reduction of heart rate at rest of 30%, during a submaximal exercise of 28% and at rest after exercise of 33%. The reduction in heart rate is still highly significant 48 hours after administration at rest, during exercise as well after administration. A smaller but still significant reduction in heart rate was found after the oral administration of 20 mg of betaxolol. Betaxolol appears to be more effective than a single oral dose of 160 mg of long-acting propranolol. No significant differences were found between 9 submaximal exercise tests performed within a period of 50 hours in normal subjects.