Which property explains why Salmeterol is preferred over Isoproterenol for long-term asthma control?

• A. is more selective for β2 adrenergic receptors
• B. has more β-agonist activity
• C. has a more rapid onset of action
• D. acts against cardiogenic shock

Answer: (A)

The key idea is that targeting the right receptor with a long-acting effect is essential for safe, ongoing asthma control. Salmeterol works by preferentially stimulating β2 receptors in airway smooth muscle, producing prolonged bronchodilation with minimal stimulation of heart β1 receptors. This selectivity means you get steady relief over a long period without marked cardiovascular side effects, which is ideal for daily maintenance. Isoproterenol, on the other hand, activates both β1 and β2 receptors (nonselective), leading to bronchodilation but also unwanted cardiac stimulation and related risks, making it unsuitable for long-term control. So, being more selective for β2 receptors explains why Salmeterol is preferred for long-term management.