The pharmacological properties of corticosteroids in relation to clinical efficacy.

The pharmacological properties of cortisol (and cortisol-like drugs) are divided into several distinct activities according to the type and cellular site of action of the hormone. To each of these discrete properties is allotted the separate clinical beneficial responses and the adverse effects that probably arise from them. For any one patient only one, or two, of these pharmacological properties are desirable and the remainder are undesirable. Therapy aims to separate the wanted from unwanted effects and this can be attempted in three ways: firstly, by adjustment of dose, frequency and duration of corticosteroid administration; secondly by delivery of the drug directly only to the site of disease--if this is possible; and thirdly, by using analogues which have been synthesized with 'tailor-made' selective actions. Synthetic analogues have not yet offered much selectivity of action of value for systemic use, but for local use (as on the skin and in the respiratory tract) such analogues have provided a considerable therapeutic advance. It is suggested that the several distinctive pharmacological properties of cortisol (as well as the existence of other steroids closely related chemically but with widely different biological activities, such as progestagens and anaesthetics) offer hope for the synthesis of cortisol-like compounds with much greater selectivity in systemic action.