Hypothalamo-pituitary-adrenal axis function in asthmatics taking low dose inhaled beclomethasone dipropionate

Anti-inflammatory drugs, particularly inhaled corticosteroids remain the mainstay of treatment of bronchial asthma. However, these drugs have potential side effects. This study was undertaken to evaluate the effects of inhaled beclomethasone dipropionate (400 and 800 micrograms) over a period of six months on the hypothalamo-pituitary-adrenal axis (HPA) suppression.

Assessment of the hypothalamo-pituitary-adrenal axis function was carried out by tetracosactrin test at time zero, (before start of treatment), three months, and six months. The baseline values served as the controls for each patient. Serum cortisol was estimated by radioimmuno assay. The response to short tetracosactrin test was classified as normal if serum cortisol levels rose at least 200 nmol/L to a minimum of 500 nmol/L.

There were seven patients who were inhaling beclomethasone dipropionate in a dose of 400 micrograms/day and another seven patients were taking the same drug in a dose of 800 micrograms/day. There was no side effect of the drug in any patient except in one patient who had dysphonia. The mean basal cortisol levels were normal in all the subjects at 0, 3 and 6 months of therapy. Tetracosactrin stimulation test was also normal in all patients at all the times who were receiving the dose of 400 micrograms/day. However, one patient (14%) receiving 800 micrograms/day had HPA axis suppression at six months. Two patients in this group also had low basal cortisol levels. There was no clinical evidence of such suppression/deficiency.

Beclomethasone dipropionate in a dose of 800 micrograms/day may suppress the hypothalamo-pituitary-adrenal axis if used for long periods (six months). However, this may not have any clinical significance.