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 six 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 adrenal cortical suppression for two or more days. Other corticoids, including methylprednisolone, hydrocortisone, prednisone, and prednisolone, are considered to be short acting (producing adrenal cortical suppression for 1¼ to 1½ days following a single dose) and thus are recommended for alternate day therapy.
Main results: All trials were small and no data could be pooled. Carry‐over effects were present in at least one cross‐over trial. Data from six trials produced the same pattern, in which prednisolone ‐12 mg/day appeared to be as effective as inhaled steroid 300‐2000 mcg/day. In two trials, inhaled steroid 300‐400 mcg/day was more effective than prednisolone 5 mg/day. All doses of inhaled steroid appeared to be more effective than alternate day doses of prednisolone up to 60 mg on alternate days. Side‐effect data were reported too variably to permit comparisons. A 30% incidence was reported in one study in patients receiving prednisolone 5 mg/day, none were reported in patients on inhaled steroids.