Kay My 14 year old daughter has CAH (non-salt wasting). Last year, the endo switched her from hydrocortisone to the prednisone. She began taking 1 5mg tablet prednisone in the morning and 1 - 5 mg tablet before bed. We had some concerns that the dose was slightly too high. I also had concerns when she became very involved with several sports teams and would noticeably appear to need water more frequently than the others. The endo then lowered the prednisone and also added the fludrocortisone. She now takes 1/2 tablet of fludrocortisone plus a 1/2 tablet prednisone in the morning and 1 tablet of prednisone at bedtime. Her recent blood tests indicate her levels are in the normal range. My daughter also says she feels much better. The way the endo described it to us is that the fludrocortisone acts upon the prednisone (or cortisone) to make it more efficiently absorbed in the body and therefore could lower the dose. Also, the fludrocortisone is part of the "cortisone" family and lessening the prednisone just by a small amount was logical. Hope this helps. Peg