The evolution of β2-agonists

Abstractβ-agonists have been widely used in the treatment of asthma for many years. Although concerns have been expressed over their safety, based largely upon epidemics of increased mor tality in asthmatics associated with high doses of isoprenaline in the 1960s and fenoterolin the 1970s and 1980s, the specific β2-agonists are vital drugs in asthma management. The short-acting β2-agonists have an important prophylactic role in the prevention of exercise-induced bronchoconstriction, and are essential in the emergency treatment of severe asthma. However, little if any benefit seems to be derived from regular use of short-acting β2-agonists and regular or frequent use can increase the:severity of the condition. The development of β2-agonists with long-acting properties, such as salmeterol and formoterol, has provided advantages over short-acting β-agonists, such as prolonged bronchodilation, reduced day-and night-time symptoms and improved quality of sleep, and has reduced the requirement for short-acting β2-agonists as relief medication. Both drugs are well tolerated and, when added to inhaled corticosteroids, produce greater improvement in lung function than increased steroid dose alone. Because of its rapid onset of action, formoterol also has the potential to be used for as-needed bronchodilator therapy in asthma