Cortone is a brand name for cortisone acetate and Cortef is a brand name for hydocortisone. Both are used as a cortisol replacement our CAH kids. The difference is in the basic chemical structure. They also have different absorption rates. The hydrocortisone is released into the bloodstream at a quicker rate.. We found this out the hard way. One time while searching for a smaller (5 mg) cortef tablet, the phamacist filled my daughter's prescription with the Cortone tablets (cortisone acetate). Within a day I knew something was wrong when she became edgy and extremely cranky. I immediately called the pharmacy and we found out the error. The pharmacist switched the prescription and was not aware of the subtle differences. I have heard of other kids successfully using the Cortone but it obviously wasn't for my daughter. She returned to her normal self when she was back on the Cortef (hydrocortisone)tablets.