ICS & HPA Axis Suppression: How Important is it & How should it be Managed?

Corticosteroids are very important in treating bronchoconstrictive lung disorders. However, inhaled corticosteroid (ICS) preparations play a central role in treating COPD and asthma, limiting the exposure to systemic steroid therapy and its long-term consequences.

More potent ICS therapy has significant absorption across the lungs, leading to hypothalamic-pituitary-adrenal (HPA) axis suppression, iatrogenic Cushing’s syndrome, adrenal insufficiency, very rarely osteoporosis, growth failure in children and development of posterior subcapsular cataract. This is much higher 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, like ritonavir and antidepressant drugs.

There are different ICS available like beclomethasone dipropionate (BDP), budesonide, ciclesonide, fluticasone propionate and mometasone furoate. They all have common mode of action by binding to glucocorticoid receptors. Early detection of adrenal suppression after ICS therapy is required and biochemical testing needs to be done to confirm the diagnosis, and careful patient education about the need for steroid supplementation at times of stress is an important part of management.