Immediate haemodynamic effects of atenolol, bopindolol and placebo

We gave eight young, healthy subjects cumulative intravenous doses of bopindolol (0.25–2 mg), atenolol (2.5–20 mg) and placebo in random order on three different days. The changes in heart rate, cardiac output (impedance technique) and blood pressure were determined during supine rest after atenolol, bopindolol or placebo given in four doses at 1-h intervals. Atenolol reduced the heart rate and cardiac output by a maximum of 16 and 22%, respectively. Mean blood pressure was unchanged and total peripheral resistance increased by 28%. Bopindolol had a somewhat lesser effect; the heart rate was lowered by 14% and cardiac output by 16%. Mean blood pressure was again unchanged and total peripheral resistance increased by 21%. One hour after the last dose, the heart rate and blood pressure were measured during upright cycle exercise. The heart rate was approximately 150 beats/min in the placebo study. Atenolol reduced the heart rate by 19%, and systolic (SBP) and diastolic blood pressure (DBP) by 21/7%, whereas bopindolol reduced the heart rate by 26% and SBP/DBP by 31/-4%. We conclude that bopindolol is an effective β-adrenoceptor blocking drug with a moderate partial agonist activity.