Bronchodilators are medications that relax the bronchial muscles of the bronchial tubes (the airways of the lungs). Relaxing these muscles makes the airways larger, allowing air to pass through the lungs more easily. They are mainly used for lung diseases, in particular asthma. Bronchodilator medication is produced in inhaled, tablet, liquid, and injectable forms, but the most widely used method of taking them is by inhalation.

There are many types of bronchodilators, and while they all dilate the bronchi, they all work in different ways to do so. Bronchodilator medication can therefore be combined to achieve the optimum results. Bronchodilators are classified into two types: Short acting and long acting. Short acting bronchodilators are also known as ‘relief’ or ‘rescue’ bronchodilators, used to provide quick relief from sudden flares of asthma symptoms. They can take effect in 20 minutes or less, and their effects are temporary, lasting for 2 to 4 hours.

Long acting bronchodilators are long-term medications taken regularly (usually twice a day) to control and prevent bronchoconstriction, or constriction of the airways. They are used for long term treatment of asthma. They take much longer to take effect, but last for up to 12 hours.