The natural history of chronic obstructive pulmonary disease (COPD) is characterised by an accelerated annual decline in forced expiratory volume in one second (FEV₁). One of the most crucial factors in COPD is therefore the means by which this annual decline can be delayed. Bronchodilator therapy is usually prescribed to relieve the symptoms, reverse airway obstruction and, hopefully, to slow the rate of disease progression and decelerate the decline in pulmonary function. However, the Lung Health Study, in its five year observation of almost 6000 patients at risk of developing COPD,1 reported that the rate of decline of lung function in smokers with mild to moderate COPD could be significantly slowed by smoking cessation but not by bronchodilator therapy.

Nonetheless, bronchodilators are an important form of treatment to reduce symptoms in COPD. As any improvement in airflow might be extremely important in these patients, the recent BTS guidelines for the management of COPD2 state that bronchodilators are the cornerstone of symptomatic treatment for the reversible component of airway obstruction. Short acting β₂ agonists used as required are recommended to be tried first in view of their more rapid relief of symptoms. If β agonists do not control symptoms adequately or if regular maintenance therapy is desired, an anticholinergic agent can be added or substituted. The addition of oral theophylline should only be considered if inhaled treatments have failed to provide enough benefit.