2agonisten

2-agonisten are medicines that selectively activate beta-2 adrenergic receptors in the airway smooth muscle, producing bronchodilation. By stimulating these receptors, they activate the Gs protein–adenylate cyclase–cAMP pathway, leading to relaxation of bronchial smooth muscle and easier breathing. While many preparations are beta-2 selective, high doses can also engage beta-1 receptors, causing cardiovascular effects.

They are usually classified by duration of action. Short-acting beta-2 agonists (SABA), such as salbutamol (albuterol) and terbutaline, provide rapid relief of acute symptoms and are commonly used as rescue inhalers. Long-acting beta-2 agonists (LABA), including salmeterol, formoterol, vilanterol, and indacaterol, have a slower onset but provide prolonged bronchodilation for maintenance therapy. Ultra-long-acting agents with very extended effects also exist in some markets. LABA are generally used in chronic obstructive pulmonary disease (COPD) and, in asthma, must be combined with inhaled corticosteroids due to safety concerns when used alone.

Clinical use focuses on relieving acute bronchospasm (SABA) and providing long-term control in COPD, with asthma management emphasizing simultaneous inhaled corticosteroids for patients receiving LABA therapy. Patients typically inhale these medications, which minimizes systemic exposure; however, systemic side effects such as tachycardia, tremor, anxiety, and, less commonly, hypokalemia can occur, especially with higher doses or systemic absorption.

In summary, 2-agonisten are beta-2 receptor–targeted bronchodilators central to the treatment of bronchial airway diseases, with distinct short- and long-acting profiles guiding their clinical use.