The recent article by Harrison and colleagues has limitations which were not adequately addressed.1 It was perhaps hardly surprising to find no differences in plasma budesonide concentrations between normal and asthmatic subjects due to the higher levels and a relatively insensitive assay compared with fluticasone.

The respective dry powder inhaler devices for each drug differ markedly in their fine particle dose delivery which will determine peripheral lung deposition and, in turn, systemic absorption. The fine particle dose expressed as a percentage of the nominal dose for fluticasone Accuhaler (Diskus) is 12% compared with 40% for budesonide Turbuhaler.2 Moreover, there is a much higher proportion of coarse particles from the Accuhaler than from the Turbuhaler.3 The study was therefore biased towards showing greater attenuation of peripheral lung absorption with fluticasone Accuhaler in asthmatic subjects.

The authors state that they are unaware of any previous direct comparisons of the effects of fluticasone and budesonide on osteocalcin concentrations. In adult asthmatic subjects steady state dosing for 12 days showed greater percentage suppression with fluticasone than with budesonide of 08.00 hour plasma cortisol levels compared with …