The complementary role of glucocorticosteroids and long-acting β-adrenergic agonists

P,-adrenergic agonists and corticosteroids can interact to produce beneficial effects on airway function. The regular use of short-acting, B 2,- adrenergic agonists as relief therapy is safe and effective; however, some degree of caution may be required with the use of very high doses. Longacting fi,-adrenergic agonists provide further benefits in terms of asthma control in patients already established on inhaled corticosteroid therapy. The mechanism by which this interaction occurs remains to be elucidated, but may involve a protective effect of corticosteroids on dysfunctional P-adrenergic receptor expression and function. In asthma, there may be a degree of uncoupling of the airway receptors, probably caused by cytokines such as IL-lP. However, this has not been established yet. Furthermore, P-adrenergic receptormediated effects may be more quickly downregulated with &receptor stimulation, leading to a reduction in anti-inflammatory effects. The regular use of corticosteroids leads to an inhibition of cytokine production and prevents P-adrenergic receptor downregulation, allowing P,-adrenergic agonists to be more effective. Further research, which may lead to a greater understanding of these mechanisms, may also lead to the development of more effective treatment regimens. © 1998. Munksgaard.