Systemic effects of intranasal steroids: An endocrinologist's perspective

Intranasal steroids (INSs) are established its first-line treatment for all ergic rhinitis, Extensive use of INSs with few reported adverse events supp orts the safety of these medications. Nevertheless, the prescription of mor e potent LNSs for consistent and more prolonged use to younger and older pa tients, often in combination with inhaled corticosteroids, justifies the ca reful examination of their potential adverse systemic effects. Systemic bio availability of INSs, by way of nasal and intestinal absorption, can be sub stantial; but current INSs vary significantly in their degree of first-pass hepatic inactivation and clearance from the body of the swallowed drug. Fo r safety studies of INSs, distinguishing detectable physiologic perturbatio ns from important adverse events is aided by an understanding of normal end ocrine physiology and the methods used to test these systems. A review of a vailable information indicates that (1) sensitive tests can measure the eff ects of INSs on biologic feedback systems, but they do not accurately predi ct clinically relevant adverse effects; (2) the primary factors that influe nce the relationship between therapeutic and adverse systemic effects of IN Ss are dosing frequency and efficiency of hepatic inactivation of swallowed drug; (3) INS treatment in recommended doses does not cause clinically sig nificant hypothalamic-pituitary-adrenal axis suppression; (4) growth suppre ssion can occur with twice-daily administration of certain INSs but does no t appear to occur with once-daily dosing or with agents with more complete first-pass hepatic inactivation; (5) harmful effects of INSs on bone metabo lism have not yet been adequately studied but would not be expected with th e use of an INS dose and dosing frequency that do not suppress basal hypoth alamic-pituitary-adrenal axis function or growth; and (6) these conclusions apply to INS treatment alone and in recommended doses-the risk of adverse effects in individual patients who are treated with LNSs is increased by ex cessive dosing or concomitant inhaled cortico-steroid or other topical cort icosteroid therapy.