The effect of topical nasal betamethasone drops for nasal polyposis on adrenal function

Abstract

Aims: Excessive use of exogenous corticosteroids may produce suppression of endogenous cortisol production. The aim of this study was to assess the effect of a standard 6-week regime of betamethasone topical nasal drops upon endogenous cortisol production using 9 AM cortisol and a physiological dose (1 μg) intravenous ACTH test. Methods: The study was approved by the Nottingham University Hospital Ethics Committee. Nine patients with nasal polyps who had not previously received exogenous corti costeroids in any form were recruited. All gave informed consent to participate and had normal standard biochemistry and thyroid function tests. Subjects underwent measurement of 9 AM cortisol and 1 μg ACTH stimulation test with a further five cortisol sampling points over 35 min. Subjects were then provided with betamethasone nasal drops, an explanation of the correct administration technique together with an explanatory leaflet. Subjects returned 6 weeks later for an identical testing and were reviewed in the Otorhino laryngology clinic. Results: Mean 9 AM cortisol fell from 402 nmol l−1 (range 250–630) before treatment to 153 nmol l−1 (<30–480). The mean maximal rise in cortisol fell from 302 nmol l−1 (110–580) to 210 nmol l−1 (10–360). At all sampling points cortisol concentration was lower after betamethasone treatment (P < 0.0001-ANOVA for repeated measures). Conclusions: Six weeks’ treatment with betamethasone significantly suppresses endogenous cortisol production in patients with nasal polyposis. The use of betamethasone drops in these patients should be regarded as systemic adminis tration of corticosteroids and the short and long term sequelae of such treatment should be borne in mind.