A Beta-adrenergic agonist medication is a bronchodilator medicine that opens the airways by relaxing the muscles around the airways that may tighten during an asthma attack or in COPD (chronic obstructive pulmonary disease).
Opening (dilating) airways helps to relieve shortness of breath. Beta-agonists can be administered by inhalers or orally. Albuterol is an example of a beta-agonist.