bronchodilators

Bronchodilators are medicines that relieve bronchial smooth muscle constriction in obstructive airway diseases by widening the airways and improving airflow. They are a cornerstone of treatment for conditions such as asthma and chronic obstructive pulmonary disease (COPD), and may be used for relief of acute symptoms or for long-term disease control.

Major drug classes include short-acting beta-2 agonists (SABAs) such as albuterol and terbutaline, providing rapid relief of bronchospasm. Long-acting beta-2 agonists (LABAs) such as salmeterol and formoterol offer prolonged effect for maintenance, typically with inhaled corticosteroids in asthma and in COPD regimens. Anticholinergic agents, including ipratropium and tiotropium, reduce bronchoconstriction by blocking muscarinic receptors and are important in COPD; ipratropium may be used as rescue therapy. Methylxanthines such as theophylline are older, with modest bronchodilation but a narrow therapeutic window and drug interactions. PDE-4 inhibitors like roflumilast reduce COPD inflammation and help decrease exacerbations rather than provide rapid bronchodilation.

Most bronchodilators are delivered by inhalation (metered-dose inhalers, dry powder inhalers, or nebulizers), which concentrates the drug in the lungs and minimizes systemic exposure. Oral or intravenous forms may be used in certain circumstances, but carry higher systemic effects.

Common adverse effects include tachycardia, tremor, and nervousness with beta-2 agonists; dry mouth and throat irritation with anticholinergics; nausea, vomiting, or arrhythmias with theophylline. Dose adjustments and monitoring are important, especially with theophylline and in patients with cardiovascular disease, the elderly, or those taking interacting medications.

Bronchodilators are used as rescue therapy for acute symptoms (particularly SABAs) and as maintenance therapy (LABAs and anticholinergics, alone or with corticosteroids) to reduce symptoms and exacerbations. They are chosen based on disease, severity, and comorbidities, with attention to safety and guidelines.