Over-reliance on β ₂-agonists may worsen the clinical course Bronchodilators in asthma: How effective and safe?

β ₂-Agonists, ipratropium, and theophylline relieve asthma symptoms by relaxing bronchial smooth muscle; none have clinically relevant anti-inflammatory properties. Bronchodilators may be used alone for mild, intermittent asthma. However, if symptoms occur more than three times weekly or more than twice monthly at night, use an inhaled anti-inflammatory drug as primary therapy and a shorter-acting inhaled β ₂-agonist as a "rescue" medication for breakthrough symptoms. If needed, a long-acting bronchodilator may be added to control nighttime symptoms. Long-term use of bronchodilators as the only therapy for moderate to severe asthma may increase airway responsiveness, cause tolerance, delay recognition of worsening asthma, and prevent timely initiation of anti-inflammatory therapy.