In the asthma regimen Seretide (fluticasone and salmeterol) 250 mcg, one puff twice daily, which component provides long-acting bronchodilation?

• A. Fluticasone
• B. Montelukast
• C. Salmeterol
• D. Theophylline

Answer: (C)

Long-acting bronchodilation in this inhaler comes from the long-acting beta-2 agonist component. Salmeterol binds to beta-2 receptors in airway smooth muscle, increasing cAMP and causing muscle relaxation, which leads to bronchodilation that lasts about 12 hours. That’s why it provides the sustained airway widening needed for daily maintenance.

Fluticasone is an inhaled corticosteroid that reduces airway inflammation and hyperresponsiveness over time, but it does not act as a bronchodilator. Montelukast is a leukotriene receptor antagonist that helps with inflammation and some triggers but is not a bronchodilator. Theophylline is an older bronchodilator with a narrow safety window and isn’t part of this regimen.