Suppression of Plasma Hydrocortisone Levels

Abstract

The relative degree of absorption of methylprednisolone acetate when administered by the rectal and oral routes was studied in 12 normal male subjects. The plasma samples were assayed for methylprednisolone and endogenous hydrocortisone concentrations. After the administration of equal doses of methylprednisolone acetate by the rectal and oral routes, the plasma hydrocortisone levels were not significantly different from each other; but the plasma concentrations of methylprednisolone were significantly lower after rectal administration than after oral administration. We conclude that the practice of utilizing the degree of suppression of endogenous hydrocortisone levels as an indicator of the extent of absorption of rectally administered glucocorticoids is inappropriate.