bronchodilator /-dilā″tər/ , a substance, especially a drug, that relaxes contractions of the smooth muscle of the bronchioles to improve ventilation to the lungs. Pharmacological bronchodilators are prescribed to improve aeration in asthma, bronchiectasis, bronchitis, and emphysema. Commonly used bronchodilators include albuterol, terbutaline, and various derivatives and combinations of these drugs. The adverse effects vary, depending on the particular class of the bronchodilating drug. In general, bronchodilators are given with caution to people with impaired cardiac function. Nervousness, irritability, gastritis, or palpitations of the heart may occur.
