Objective: To appraise the data on systemic adverse effects of inhaled corticosteroids.
Methods: A computerized database search from January 1, 1966, through July 31, 1998, using MEDLINE, EMBASE, and BIDS and using appropriate indexed terms. Reports dealing with the systemic effects of inhaled corticosteroids on adrenal gland, growth, bone, skin, and eye, and reports on pharmacology and pharmacokinetics were reviewed where appropriate. Studies were included that contained evaluable data on systemic effects in healthy volunteers as well as in asthmatic children and adults. A statistical meta-analysis using regression was performed for parameters of adrenal suppression in 27 studies.
Results: Marked adrenal suppression occurs with high doses of inhaled corticosteroid above 1.5 mg/d (0.75 mg/d for fluticasone propionate), although there is a considerable degree of interindividual susceptibility. Meta-analysis showed significantly greater potency for dose-related adrenal suppression with fluticasone compared with beclomethasone dipropionate, budesonide, or triamcinolone acetonide, whereas prednisolone and fluticasone propionate were approximately equivalent on a 10:1-mg basis. Inhaled corticosteroids in doses above 1.5 mg/d (0.75 mg/d for fluticasone propionate) may be associated with a significant reduction in bone density, although the risk for osteoporosis may be obviated by post-menopausal estrogen replacement therapy. Although medium-term growth studies showed suppressive effects with 400-microg/d beclomethasone dipropionate, there was no evidence to support any significant effects on final adult height. Long-term, high-dose inhaled corticosteroid exposure increases the risk for posterior subcapsular cataracts, and, to a much lesser degree, the risk for ocular hypertension and glaucoma. Skin bruising is most likely to occur with high-dose exposure, which correlates with the degree of adrenal suppression.
Conclusions: All inhaled corticosteroids exhibit dose-related systemic adverse effects, although these are less than with a comparable dose of oral corticosteroids. Metaanalysis shows that fluticasone propionate exhibits greater dose-related systemic bioactivity compared with other available inhaled corticosteroids, particularly at doses above 0.8 mg/d. The long-term systemic burden will be minimized by always trying to achieve the lowest possible maintenance dose that is associated with optimal asthmatic control and quality of life.