The rationale for pharmacologic therapy in stable chronic obstructive pulmonary disease.

The structural changes in airways and alveoli that characterize chronic obstructive pulmonary disease (COPD) result from an abnormal and persistent inflammatory reaction to inhaled noxious particles or gases, notably tobacco smoke. This remodeling of the lung leads to irreversible airflow obstruction. However, COPD should be viewed by clinicians as a treatable condition, since most patients with COPD have an additional reversible component related to increased bronchomotor tone. The use of bronchodilators, especially anticholinergics and beta2-agonists, results in a reduction in airway smooth muscle tone and airflow resistance; this translates into marked improvement in significant clinical outcomes such as dyspnea, quality of life, and exercise capacity. An increasing amount of evidence supports the idea that long-acting agents have more significant impact in these parameters than the short-acting preparations.