Corticosteroids are steroid hormones with potent anti-inflammatory and immunosuppressive properties, widely used across virtually every medical specialty for conditions involving inflammation, allergy, and autoimmunity. They are classified into glucocorticoids and mineralocorticoids based on their predominant receptor activity, though synthetic derivatives display varying degrees of selectivity.
What Are Corticosteroids?
Corticosteroids are produced endogenously in the adrenal cortex and regulate numerous physiological processes including metabolism, immune function, fluid balance, and stress responses. Glucocorticoids such as cortisol modulate carbohydrate metabolism and suppress inflammation, while mineralocorticoids such as aldosterone regulate electrolyte and fluid balance. Synthetic corticosteroids are designed to maximize desired anti-inflammatory effects while minimizing undesirable metabolic and mineralocorticoid effects.
Mechanism of Action
Corticosteroids exert their effects by binding to the cytoplasmic glucocorticoid receptor, which then translocates to the nucleus and regulates gene transcription. Transrepression of pro-inflammatory transcription factors such as nuclear factor kappa B and activator protein 1 reduces the production of cytokines, chemokines, adhesion molecules, and inflammatory enzymes including cyclooxygenase-2 and phospholipase A2. Transactivation increases the synthesis of anti-inflammatory proteins such as lipocortin-1 and I kappa B alpha.
These genomic effects require hours to manifest fully, which explains the delayed onset of therapeutic action. Rapid non-genomic effects mediated by membrane-associated receptors also contribute to immediate vasoconstriction and reduced edema formation. The therapeutic index of corticosteroids is limited by their broad range of genomic effects, which account for both therapeutic and adverse actions.
Therapeutic Uses
Corticosteroids are used for their anti-inflammatory effects in conditions including asthma, chronic obstructive pulmonary disease, inflammatory bowel disease, rheumatoid arthritis, systemic lupus erythematosus, and allergic disorders. They are essential for preventing and treating acute graft rejection in transplantation and managing autoimmune hepatitis, nephrotic syndrome, and inflammatory skin conditions. High-dose corticosteroids are critical in anaphylaxis, severe asthma exacerbations, and cerebral edema.
Prednisone and prednisolone are intermediate-acting glucocorticoids widely used for chronic inflammatory conditions. Dexamethasone is a potent, long-acting glucocorticoid used for cerebral edema, severe inflammation, and COVID-19 management. Hydrocortisone has both glucocorticoid and mineralocorticoid activity and is used as replacement therapy in adrenal insufficiency.
Adverse Effects
Chronic corticosteroid use causes a well-characterized constellation of adverse effects. Metabolic effects include hyperglycemia, diabetes mellitus, weight gain with central obesity, and osteoporosis. Immunosuppression increases infection risk and can reactivate latent infections. Musculoskeletal effects include myopathy and osteonecrosis. Dermatological effects include skin thinning, striae, and impaired wound healing. Psychiatric effects range from mood changes to psychosis. Growth suppression occurs in children. Adrenal suppression with secondary adrenal insufficiency results from chronic suppression of the hypothalamic-pituitary-adrenal axis, necessitating gradual withdrawal.
Contraindications
Systemic corticosteroids should be used with caution in patients with diabetes, hypertension, osteoporosis, glaucoma, and active infections. Live vaccines are contraindicated during high-dose corticosteroid therapy. Relative contraindications include peptic ulcer disease and recent surgery.
Conclusion
Corticosteroids are indispensable therapeutic agents whose potent anti-inflammatory effects are balanced by significant toxicity with long-term use. Strategies to minimize adverse effects include using the lowest effective dose, employing local administration when possible, and implementing preventive measures for osteoporosis and other complications.
