Inhaled corticosteroids and the hypothalamic-pituitary-adrenal axis

Introduction: Inhaled corticosteroids (ICS) have a very favourable ratio of topical versus systemic activity. To assess the systemic availability and/or potency of different types of ICS, measurements are used that reflect the function of the hypothalamic-pituitary-adrenal (HPA) axis. It has been shown that ICS may, in a dose-dependent manner, reduce cortisol secretion into serum (reflected in a reduced area under the concentration-time curve [AUC] and overnight or 24-hour urinary free cortisol [UFC] excretion) and total cortisol metabolite output. As a consequence, one would expect that the greater the pulmonar…