Abstract

Eleven β-adrenoceptor blocking drugs are now available in Britain. All share the same basic structure and act by competition at the β-adrenoceptor. We have previously discussed propranolol, oxprenolol, practolol and pindolol,^{1 2} as well as labetalol which also blocks α-receptors³ and is not dealt with in this article. The others are acebutolol, atenolol, metoprolol, nadolol, sotalol and timolol. Pharmacologically they differ in three ways - their relative capacity to block effects on β₁ - (cardiac) and β₂ - (lung, blood vessel) adrenoceptors, their local anaesthetic (membrane-stabilising) action, and their partial-agonist (intrinsic sympathomimetic) activity. They also differ in pharmacokinetic properties, convenience and cost. These differences determine the choice.