oa Safety of Inhaled Corticosteroids. Why the Variation in Systemic Adverse Effects?

Inhaled corticosteroids (ICS) are currently the mainstay of therapy in persistent childhood asthma. However, systemic adverse effects of various available agents - particularly on growth, bone metabolism, and the hypothalamicpituitary- adrenal (HPA) axis - continue to concern the families of asthmatic children, and are debated within the medical community. Although there is short- and medium-term suppressive effect of usual doses of ICS on linear growth, the findings of long term studies are reassuring, suggesting attainment of the full potential of adult height. ICS do not appear to exert significant untoward effects on bone mineral density. Measurable systemic effect of ICS by sensitive measurements of function of the HPA axis does not necessarily translate into clinically significant side effects. However, use of higher than recommended doses of ICS may on occasion lead to symptomatic adrenal insufficiency and should be of concern; there may be important differences among available compounds regarding such potential. Variation in adverse effects of ICS is explained by differences in their pharmacokinetic and pharmacodynamic properties, formulation and delivery devices, and patient factors such as degree of airway obstruction, suppressive effect of airway inflammation per se on the HPA axis, genetic factors, patient training in the use of delivery devices, and compliance.