Synthetic glucocorticoids are readily absorbed from any
site of administration and bind with less avidity to
serum proteins than endogenous cortisol, thereby diffusing
more readily into the tissues. The synthetic molecules
have greater affi nity for the cytoplasmic steroid
receptor and are less rapidly degraded, both effects contributing
to a prolonged duration of action. Prednisone
and cortisone require activation in the liver to prednisolone
and cortisol respectively, so the use of these agents
topically or with end-stage liver disease is generally
considered to be contraindicated.