Salmeterol xinafoate is a long-acting, selective β2-adrenergic agonist with bronchodilator actions (EC50 = 0.25 μM) that has been used clinically to treat asthma and COPD. It demonstrates 2,818-fold selectivity for β2-adrenergic receptors over β1-adrenergic receptors. Salmeterol binds to an exosite domain of β2-adrenergic receptors, producing a slow onset of action and prolonged activation.
