Inhaled β₂-Adrenoceptor Agonists

Although large surveys have documented the favourable safety profile of β₂-adrenoceptor agonists (β₂-agonists) and, above all, that of the long-acting agents, the presence in the literature of reports of adverse cardiovascular events in patients with obstructive airway disease must induce physicians to consider this eventuality. The coexistence of β₁- and β₂-adrenoceptors in the heart clearly indicates that β₂-agonists do have some effect on the heart, even when they are highly selective. It should also be taken into account that the β₂-agonists utilised in clinical practice have differing selectivities and potencies. β₂-agonist use has, in effect, been associated with an increased risk of myocardial infarction, congestive heart failure, cardiac arrest and sudden cardiac death. Moreover, patients who have either asthma or chronic obstructive pulmonary disease may be at increased risk of cardiovascular complications because these diseases amplify the impact of these agents on the heart and, unfortunately, are a confounding factor when the impact of β₂-agonists on the heart is evaluated. Whatever the case may be, this effect is of particular concern for those patients with underlying cardiac conditions. Therefore, β₂-agonists must always be used with caution in patients with cardiopathies because these agents may precipitate the concomitant cardiac disease.