Bronchodilators are a group of medications that help breathing by keeping the airways dilated. That being said, they are typically used in obstructive lung diseases, like asthma and chronic obstructive pulmonary disease, or COPD for short, where clients suffer from narrowing and obstruction of the airways.
Asthma is characterized by chronic inflammation in the lungs, as well as asthma exacerbations or attacks, where certain triggers, such as viruses, allergens, stress, aspirin or other NSAIDs and exercise, lead to reversible bronchial smooth muscle spasms and mucus production, both of which make it hard to breathe. As a result, clients experience symptoms like dyspnea, wheezing, chest tightness, and coughing.
On the other hand, in COPD, there’s chronic inflammation and fibrosis in the lungs, most commonly due to smoking. As a result, the airways become irreversibly obstructed and the lungs are not able to empty properly, which leaves air trapped inside the lungs. As a result, clients experience symptoms like dyspnea and a productive cough.
Now, COPD generally refers to a group of progressive lung diseases that includes chronic bronchitis and emphysema. These two differ in that chronic bronchitis is defined by long-term inflammation of the bronchial tubes, whereas emphysema is defined by destruction and enlargement of the alveoli.
Although the airway obstruction in COPD is irreversible, bronchodilators can often help prevent the complete closure of the airway during expiration, which provides mild symptomatic relief.
Now, based on their mechanism of action, bronchodilators can be broadly divided into three main groups; β2-agonists; anticholinergics; and methylxanthines.