Aimee,

I am not sure if your question was addressed to me, but if so....

If you look on standard drug equivalency tables, prednisone is generally considered to be about 5 times stronger than hydrocortisone.  So, 25 mg of hc would be closer to 5 mg of prednisone, not 7.5 mg.

However, standard drug equivalency tables generally reflect the relative potency of the different glucocorticoids based on their ability to treat inflammation, not their ability to suppress adrenal androgen production, as would be the case with CAH.  Recent studies on CAH patients show that, when used to suppress adrenal androgen production, the relative potency of prednisone relative to hydrocortisone, may be much higher...closer to 10 times stronger.  Therefore, 25 mg of hc may actually only be equivalent to 2.5 mg of prednisone....a far cry from 7.5 mg.  Recent studies on dexamethasone used in CAH patients show much the same thing.