β-blockers are not all the same: pharmacologic similarities and differences, potential combinations and clinical implications

Abstract

β-blockers are a heterogeneous class, with individual agents distinguished by selectivity for β1- vs. β2- and α-adrenoceptors, presence or absence of partial agonist activity at one of more β-receptor subtype, presence or absence of additional vasodilatory properties, and lipophilicity, which determines the ease of entry the drug into the central nervous system. Cardioselectivity (β1-adrenoceptor selectivity) helps to reduce the potential for adverse effects mediated by blockade of β2-adrenoceptors outside the myocardium, such as cold extremities, erectile dysfunction, or exacerbation of asthma or chronic obstructive pulmonary disease. According to recently updated guidelines from the European Society of Hypertension, β-blockers are included within the five major drug classes recommended as the basis of antihypertensive treatment strategies. Adding a β-blocker to another agent with a complementary mechanism may provide a rational antihypertensive combination that minimizes the adverse impact of induced sympathetic overactivity for optimal blood pressure-lowering efficacy and clinical outcomes benefit.