The site www.onhealth.com had some things about Florinef (it was under Fludrocortisone on that site). Some of these things are that "fludrocortisone can cause slow growth in kids/adolescents, can cause headaches, if on any other steriods its' use can cause both medicines to be less effective, can cause weakened bones because it causes more calcium to pass into the urine. Florinef's life is 18-36 hours, but I also read that it's time varies from person to person and that could cause it to not even act for 18 hours - it's purpose is to cause more salt to enter the bloodstream. We have been on .1 mg tablet in the morning only ... but I'm concerned & am thinking to change to 1/2 morning, other 1/2 evening. Hear so often about people's children having dark circles under their eyes, thinking not getting enough salt, but ... it could be that the Florinef isn't working for the whole 24 hours.