Necrosis of hips and joints: A serious complication of long-term use of corticosteroids is aseptic necrosis of the hip joints. Aseptic necrosis is a condition in which there is death and degeneration of the hip bone. It is a painful condition that ultimately can lead to the need for surgical replacement of the hip. Aseptic necrosis also has been reported in the knee joints. The estimated incidence of aseptic necrosis among long-term users of corticosteroids is 3%-4%. Patients taking corticosteroids who develop pain in the hips or knees should report the pain to their doctors promptly.
During conventional pharmacologic dose corticosteroid therapy, ACTH production is inhibited with subsequent suppression of cortisol production by the adrenal cortex. Recovery time for normal HPA activity is variable depending upon the dose and duration of treatment. During this time the patient is vulnerable to any stressful situation. Although it has been shown that there is considerably less adrenal suppression following a single morning dose of prednisolone (10 mg) as opposed to a quarter of that dose administered every 6 hours, there is evidence that some suppressive effect on adrenal activity may be carried over into the following day when pharmacologic doses are used. Further, it has been shown that a single dose of certain corticosteroids will produce adrenocortical suppression for two or more days. Other corticoids, including methylprednisolone, hydrocortisone, Prednisone, and prednisolone, are considered to be short acting (producing adrenocortical suppression for 1¼ to 1½ days following a single dose) and thus are recommended for alternate day therapy.
As a glucocorticoid , the lipophilic structure of prednisolone allows for easy passage through the cell membrane where it then binds to its respective glucocorticoid receptor (GCR) located in the cytoplasm. Upon binding, formation of the GC/GCR complex causes dissociation of chaperone proteins from the glucocorticoid receptor enabling the GC/GCR complex to translocate inside the nucleus. This process occurs within 20 minutes of binding. Once inside the nucleus, the homodimer GC/GCR complex binds to specific DNA binding-sites known as glucocorticoid response elements (GREs) resulting in gene expression or inhibition. Complex binding to positive GREs leads to synthesis of anti-inflammatory proteins while binding to negative GREs block the transcription of inflammatory genes.