Inhaled corticosteroids and HPA axis suppression: how important is it and how should it be managed?

Inhaled corticosteroids (ICS) are established as a cornerstone of management for patients with bronchoconstrictive lung disease. However, systemic absorption may lead to suppression of the hypothalamic-pituitary-adrenal (HPA) axis in a significant minority of patients. This is more likely in 'higher risk' patients exposed to high cumulative ICS doses, and in those treated with frequent oral corticosteroids or drugs which inhibit cytochrome p450 3A4. Hypothalamic-pituitary-adrenal axis suppression is frequently unrecognized, such that some patients, notably children, only come to light when an adrenal crisis is precipitated by physical stress. To minimize this risk, 'higher risk' patients and those with previously identified suppressed cortisol responses to Synacthen testing should undergo an education programme to inform them about sick day rules. A review of ICS therapy should also be undertaken to ensure that the dose administered is the minimum required to control symptoms.