Bronchodilators and Inhaled Corticosteroids

The central safety error is treating a reliever and a controller as interchangeable. Bronchodilators relax airway smooth muscle or block bronchoconstricting parasympathetic signals. The airway opens, airflow improves, and symptoms can ease within minutes. They treat the obstruction the patient is experiencing now; they do not adequately suppress the airway inflammation that drives asthma instability. Inhaled corticosteroids (ICS) reduce airway inflammation, hyper-responsiveness and the tendency to exacerbate. Their benefit accumulates over days to weeks. An ICS is a controller, not a rescue treatment for sudden bronchospasm. A patient who feels better after salbutamol may still have active airway inflammation. Conversely, a patient whose acute wheeze does not improve after an ICS has not received a drug designed to work immediately. The inhalers have different jobs.