Medications Used for Long Term Control
• Beta-adrenergic agonists: They provide bronchodilation for up to 12 hours after a single dose. Salmeterol and formoterol are the two long- acting beta-2-agonists available for asthma in the United States. They are indicated for long-term prevention of asthma symptoms, nocturnal symptoms, and for prevention of exercise-induced bronchospasm.
• Anticholinergics: The long-acting anticholinergic tiotropium has been studied as add-on therapy.
• Phosphodiesterase inhibitors: Theophylline provides mild bronchodilation in asthmatic patients. Theophylline also has anti-inflammatory and immunomodulatory properties, enhances mucociliary clearance, and strengthens diaphragmatic contractility. Sustained-release theophylline preparations are effective in controlling nocturnal symptoms and as added therapy in patients with moderate or severe persistent asthma whose symptoms are inadequately controlled by inhaled corticosteroids.
• Leukotriene modifiers: Leukotrienes are potent biochemical mediators that contribute to airway obstruction and asthma symptoms by contracting airway smooth muscle, increasing vascular permeability and mucus secretion, and attracting and activating airway inflammatory cells. Zileuton, zafirlukast and montelukast are examples.
• Mediator inhibitors: Cromolyn sodium and nedocromil are long-term control medications that prevent asthma symptoms and improve airway function in patients with mild persistent or exercise-induced asthma. These agents modulate mast cell mediator release and eosinophil recruitment and inhibit asthmatic responses to allergen challenge and exercise-induced bronchospasm. They can be effective when taken before an exposure or exercise but do not relieve asthmatic symptoms once present.