AndrewMany thanks for that, Julia.
I looked around the Medline site and found that of these steroids for CAH, dexamethasone is the one that causes the greatest reduction in nocturnal Growth Hormone secretion. (Enter 8197019 and click on GO)
This explains the reluctance to just use dex as a matter of course. I too would be nervous of changing over, unless compliance becomes a big issue.
Andrew