Chronic obstructive pulmonary disease is an inflammatory disorder characterized by airflow limitation. Its cardinal symptom is dyspnea, which develops gradually with even low levels of exercise.

Bronchodilators (BDs) are the most effective drugs for relieving dyspnea. Two main types of BD are currently available, β-mimetics and anticholinergics, with different subtypes according to their duration of action. The most useful agents are those administered once daily, also called ‘ultralong-acting’ BDs. As a high proportion of patients remain insufficiently controlled with only one BD, all guidelines currently recommend the combination of two long-acting agents. A number of studies have demonstrated that combination therapy is functionally and, in general, clinically superior to individual drugs.

Although various combinations have been assessed, the current trend is to use ultralong-acting agents due to their more convenient dosing schedule and, probably, their greater efficacy. In the research setting, some of these agents are combined in a single device, an approach that may become the standard treatment for many patients with chronic obstructive pulmonary disease.