Effects of long-term inhaled corticosteroids on adrenal function in patients with asthma

Inhaled corticosteroids (ICSs) are effective asthma controllers, but long-term use could lead to adverse effects.

To examine adrenal responsiveness of patients with persistent asthma treated with long-term ICSs.

Morning plasma cortisol levels before and 30 minutes after adrenocorticotropic hormone (ACTH) (1 microg intravenously) stimulation were compared. Primary end points included mean prestimulation and poststimulation cortisol levels; secondary end points included morning cortisol level of 5 microg/dL or less, post-ACTH stimulation cortisol level of 18 microg/dL or less, and/or a net change of 7 microg/dL or less from baseline.

A total of 103 asthmatic patients (29 in the triamcinolone acetonide group, 18 in the flunisolide group, 45 in the fluticasone propionate group, and 11 in the oral corticosteroids group [positive controls]) completed the study. Mean daily ICS doses and durations were as follows: triamcinolone acetonide: 448 microg for 36 months; flunisolide: 1,181 microg for 41 months; and fluticasone propionate: 745 microg for 19 months. Eleven of 30 patients taking high-dose ICSs (10 of 28 taking fluticasone propionate and 1 of 2 taking flunisolide) had both low morning cortisol levels and abnormal post-ACTH stimulation cortisol levels. Few patients taking lower doses of any ICS had abnormal results.

Patients who require long-term treatment with high-dose ICSs may have abnormal morning plasma cortisol levels and reduced responsiveness to ACTH stimulation. Careful monitoring of adrenal function should be considered in such patients.