Long-acting beta(2)-agonists: how are they used in an optimal way?

Inhaled long-acting beta(2)-agonists are frequently used for the treatment of asthma. When introduced to the market, the drug was accompanied by a debate among physicians and scientists raising warnings against the use of beta(2)-agonists, leading to a risk of tachyphylaxis and worsening of asthma control. During recent years, much of these warnings have been counter proved and there has been a tendency to institute treatment with long-acting beta(2)-agonists somewhat earlier in the course than before. However, the exact place for long-acting beta(2)-agonists in the asthma treatment plans, still needs to be established. While beta(2)-agonists have been shown to have anti-inflammatory activity in vitro and after single allergen exposure, this effect seems to disappear with regular treatment. The same phenomena have been shown to protect against obstruction caused by metacholine inhalation or exercise. Although the protective effect diminishes or even disappears, no signs of rebound phenomena or increased susceptibility to provocative stimulus has been shown. Thus, in contrast to earlier reports after regular use of short-acting beta(2)-agonists, no signs of tachyphylaxis have been reported after use of long-acting beta(2)-agonists. Moreover, the bronchodilatatory effect seems to be fairly stable after regular treatment, even though some reports claims that this effect diminishes over time. The present article is a review of some data involved in this debate. The authors conclude that long-acting beta(2)-agonists are a valuable contribution to the asthma treatment repertoire. However, the drugs should be regarded as long-acting bronchodilatators, supplementing the use of inhaled corticosteroids. The rapid appearing tolerance towards allergen-induced and provoked bronchial obstruction prevents these drugs from being used as monotherapy; they should be used only in combination with sufficient anti-inflammatory treatment, i.e. inhaled corticosteroids.