Corticosteroid

Corticosteroids are a class of steroid hormones produced by the adrenal cortex and synthetic analogues used as medicines. They are broadly divided into glucocorticoids, which regulate metabolism and exert potent anti-inflammatory effects, and mineralocorticoids, which control electrolyte and water balance. The principal endogenous glucocorticoid is cortisol; aldosterone is a key mineralocorticoid.

Mechanism: Corticosteroids act by binding intracellular glucocorticoid receptors and altering gene transcription. This reduces the expression of inflammatory cytokines, chemokines, and enzymes such as COX-2, and represses activity of immune cells. They also influence vascular permeability and may have non-genomic effects at high concentrations.

Uses: They are used to treat a wide range of inflammatory and autoimmune conditions, including asthma and chronic obstructive pulmonary disease, rheumatoid arthritis, inflammatory bowel disease, dermatologic disorders, and allergic reactions. They are also used for organ transplantation to prevent rejection and as replacement therapy in adrenal insufficiency. Common synthetic agents include prednisone, prednisolone, methylprednisolone, dexamethasone, hydrocortisone, budesonide, and fluticasone.

Forms and administration: Corticosteroids can be given systemically (oral or intravenous) or locally (inhaled or intranasal, topical, intra-articular, ocular). Potency and duration vary by compound. In many conditions, the lowest effective dose is used for the shortest possible time, and gradual tapering is recommended after longer courses to minimize adrenal suppression.

Adverse effects and safety: Systemic corticosteroids can cause weight gain, high blood glucose, high blood pressure, osteoporosis, mood changes, cataracts, impaired wound healing, and increased infection risk. They can suppress the hypothalamic-pituitary-adrenal axis. Local forms cause fewer systemic effects but may cause local infections or irritation; inhaled forms may lead to oral thrush or hoarseness if not rinsed after use. Use in pregnancy and children requires careful risk–benefit assessment and monitoring.