Assessing the clinical value of fast onset and sustained duration of action of long-acting bronchodilators for COPD.

The long-acting inhaled bronchodilators available for use in chronic obstructive pulmonary disease (COPD) vary in their pharmacological class (β2-adrenergic agonist or antimuscarinic/anticholinergic, alone or combined), durations of action and speed of onset of bronchodilator effect. In the early stages of development of a maintenance bronchodilator, the goals are to identify a molecule with the theoretically 'ideal' profile of fast onset and prolonged duration of action in comparison with existing agents, while minimizing non-specific activity at organs outside the lungs. The move towards increasing duration of bronchodilator action is generally paralleled by improved effects on clinical outcomes, and the advent of more potent agents seems likely to provide an opportunity to reduce overreliance on the use of inhaled corticosteroids in treating COPD. In terms of onset of action, an immediately perceived benefit in reducing dyspnea, although not definitively demonstrated, might prove useful in increasing adherence, which is very poor among patients with COPD. Once-daily administration may also be helpful in this respect. Shared decision-making between patient and physician in the choice of treatment is important in optimizing adherence and, thus, treatment effectiveness.