Kidsolone Mechanism of Action

Pharmacology: Pharmacokinetics: Prednisolone and Prednisone are both readily absorbed from the gastro-intestinal tract, but whereas prednisolone already exist in metabolically active form, prednisone must be converted in the liver to its active metabolite, prednisolone. In general, this conversion is rapid so that prednisone has a preconversion biological half-life of only about 60 minutes. Hence, although prednisone has been estimated to have only about 80% the bioavailability. This difference is of little consequence when seen in the light of intersubject variation in the pharmacokinetics of prednisolone itself; bioavailability also depends on the dissolution rates of the tablet formulations. Nevertheless, prednisolone is the more reliably absorbed of the two corticosteroids, particularly some liver diseases where the conversion of prednisone may be diminished.
Peak plasma concentrations of prednisolone are obtained 1 or 2 hours after administration by mouth, and it has usual plasma half-life of 2 to 4 hours. Its initial absorption, but not its overall bioavailability, is affected by food.
Prednisolone is excreted in the urine as free and conjugated metabolites, together with an appreciable proportion of unchanged prednisolone. Prednisolone crosses the placenta and small amounts are excreted in breast milk.
Prednisolone has a biological half-life lasting several hours, intermediate between those of hydrocortisone and the longer acting glucocorticoids, such as dexamethasone. It is this intermediate duration of action in which makes it suitable for the alternate-day administration regimens which has been found to reduce the risk of adrenocortical insufficiency, yet provide adequate corticosteroid coverage in some disorders.