Haemodynamic effects of atenolol, pindolol and propranolol during adrenaline infusion in man

In a double blind, cross over study the haemodynamic effects of an i.v. infusion of adrenaline during concomitant administration of atenolol, pindolol, propranolol or placebo were examined in 7 healthy volunteers. During coadministration with placebo, adrenaline caused an increase in systolic blood pressure (SBP) of 26 mm Hg and a decrease in diastolic blood pressure (DBP) of 20 mm Hg. Heart rate (HR) and stroke volume (SV) were increased by about 20-30%. Total peripheral resistance (TPR) fell significantly. When the subjects were pretreated with atenolol, the adrenaline increased SBP by 16 mm Hg, the DBP did not change, HR and SV increased by 19 and 30%, and TPR fell. During concomitant administration of the non-selective betablocker pindolol, which has strong intrinsic sympathomimetic activity (ISA), adrenaline increased SBP by 11 mm Hg and DBP by 17 mm Hg. This pure pressor response led to a significant reduction in HR and SV and an increase in TPR, probably mediated through the baroreceptors. The haemodynamic response to adrenaline during coadministration of propranolol was very similar to that seen after pindolol. It is concluded that a beta1-selective blocker interferes very little with the haemodynamic response to adrenaline, whereas it is changed to a pure pressor response during coadministration of a non-selective betablockers. ISA did not significantly modify the pressor response.