Background: Inhaled corticosteroids have become a first-line treatment for chronic asthma. It has been shown that inhaled corticosteroids can have a measurable effect on the hypothalamic-pituitary-adrenal axis in asthmatic children.
Objective: To investigate the prevalence of adrenal suppression among asthmatic children receiving chronic therapy with low to moderate doses (up to 1000 micrograms) of inhaled beclomethasone dipropionate via a metered dose inhaler (MDI) and via MDI attached to a spacer device (MDI-spacer).
Methods: The study included 39 asthmatic children currently undergoing therapy; 24 received beclomethasone dipropionate by MDI attached to a spacer, and 15 directly by MDI. All the patients had been treated for at least 4 months. Another 21 children were normal controls. The 24-hour urinary free cortisol excretion was measured to evaluate hypothalamic-pituitary-adrenal axis function.
Results: Seven of 15 (47%) patients from the MDI group had reduced 24 hour-urinary free cortisol excretion and 2 of 24 (8%) in the MDI-spacer group (P = .006). The mean 24-hour urinary free cortisol excretion of the MDI group was 0.0185 +/- 0.0089 microgram/gram creatinine, and the MDI-spacer and the control groups were, 0.0290 +/- 0.0138 microgram/gram creatinine and 0.0270 +/- 0.0118 microgram/gram creatinine, respectively, (P = 0.37, f = 3.51 ANOVA).
Conclusion: Chronic inhalation of low to moderate doses of corticosteroids is associated with adrenal suppression in some asthmatic children. This side effect is more common among patients inhaling directly from the MDI and is less frequent when a large volume spacer is attached to the MDI.