Safety of high-dose inhaled corticosteroids.

Inhaled corticosteroids are being given to more patients, at increasing doses and for longer periods of time. This has led to renewed concern about side-effects, particularly when higher doses (> 1 mg day-1) are used. The side-effects of particular concern are adrenocortical suppression, bone resorption, decreased growth in children, skin thinning and cataract formation. Changes in adrenocortical function are seen in a small proportion of patients given doses of 1-2 mg day-1. Long-term studies of the effect of inhaled corticosteroids on bone density are not available. Cross-sectional studies of bone density have been performed, but confounding variables, such as previous courses of oral corticosteroids and poor matching of control groups, make the studies difficult to interpret. Short-term effects on markers of bone turnover have been demonstrated, but their relevance to the long-term risk of osteoporosis is unclear. Studies reporting an increased incidence of skin changes and cataract formation are difficult to interpret because of confounding variables and inadequate control groups. Further studies of the long-term side-effects of inhaled corticosteroids are now required to enable prescribers to judge better the relative benefits and risks of this important asthma therapy.