Bronchodilators

• Inhaled bronchodilators are the mainstay of COPD management and include β₂-agonists and anticholinergics (antimuscarinics), which are equally effective.

Examples of bronchodilators

• β₂-agonists relax bronchial smooth muscle (salbutamol)¹

• Long-acting β₂-agonists (LABAs) (such as salmeterol, formoterol) are preferable for patients with more significant symptoms in Groups B to D (see Spirometric Assessment for details). Recently, 'ultra-long' acting LABAs have been developed that require once-daily dosing (indacaterol)¹

• Anticholinergics relax bronchial smooth muscle through competitive inhibition of muscarinic receptors (M₁, M₂, and M₃) (such as ipratropium)¹

• A long-acting quaternary anticholinergic which is M₁ and M₃ selective (tiotropium) may have an advantage over ipratropium as M₂ receptor blockade may limit bronchodilation

It is not clear whether pharmacologic treatment for patients with an FEV₁ > 80% is effective. However, GOLD recommends a short-acting bronchodilator as first choice for all Group A patients.¹

The frequency of exacerbations can be reduced with the use of anticholinergics, inhaled corticosteroids, or LABAs. The initial choice among short-acting β₂-agonists, LABAs, anticholinergics (which have a greater bronchodilating effect), and combination β₂-agonist and anticholinergic therapy, is often a matter of physician and patient choice.

Reference

1. Global Initiative for chronic obstructive lung disease: Global strategy for the diagnosis, management, and prevention of COPD. 2011. www.goldcopd.org