Anti-inflammatory Effects of Corticosteroids

Glucocorticosteroids (‘steroids’) are widely used as anti-inflammatory agents. They produce a vast array of effects, primarily through their ability to bind to cytosol receptors in most (if not all) nucleated cells in the body. Steroids frequently cause the production of new proteins or increase the synthesis of other proteins.

Steroids cause major changes in the traffic patterns of lymphocytes granulocytes and monocyte-macrophages. These result in neutrophilia and lower blood concentrations of lymphocytes, eosinophils, monocytes and basophils. Such traffic changes, as well as changes in function of these cells, all diminish the influx of cells into inflammatory reactions.

Steroids most useful for systemic anti-inflammatory treatment are short-acting oral preparations such as prednisone. Given in one daily dose, these are inexpensive and effective. Various types of steroid regimens are used for different situations. Adrenal replacement therapy is not useful for inflammatory conditions. Induction of anti-inflammatory conditions usually involves moderately high doses of oral steroids for one to two weeks before tapering. Maintenance of anti-inflammatory control on a long-term basis is often not needed. If it is required, alternate-morning therapy is preferred, although some patients on low-dose daily steroids do not show much inhibition of the hypothalamic-pituitary-adrenal (HPA) axis. Large doses of intravenous corticosteroids (‘pulse therapy’) is useful in a few special situations.

Corticosteroids work in various ways in different conditions. In asthma, they do not impair IgE mechanisms, but exert anti-inflammatory actions and potentiate the effects of β-adrenergic bronchodilators. In immune complex disease, they are antipyretic, vasoconstrictive, impair the release of injurious enzymes from inflammatory cells, are antichemotactic and may interfere with prostaglandin synthesis.

Side-effects of corticosteroids are numerous but many can be avoided by the use of judicious dosing regimens. The controversy over the role of steroids in infections is reviewed.