dexamethasone

Dexamethasone is a synthetic glucocorticoid corticosteroid with potent anti-inflammatory and immunosuppressant effects. It binds to the glucocorticoid receptor, modulating transcription of inflammatory genes and suppressing the production of cytokines, prostaglandins, and other mediators. It also reduces edema and stabilizes lysosomal membranes.

Dexamethasone is used to treat a range of inflammatory and autoimmune conditions, including allergic reactions, asthma, chronic obstructive pulmonary disease exacerbations, rheumatoid arthritis, inflammatory bowel disease, and various dermatologic or ophthalmic inflammatory disorders. It is also employed in oncology as supportive therapy to reduce edema and to help control chemotherapy-induced nausea and vomiting. In severe COVID-19, a daily dexamethasone dose reduced mortality in patients requiring supplemental oxygen or ventilation (as shown in clinical trials).

Dosing forms include oral tablets and injectable solutions for intravenous or intramuscular use, as well as topical, ophthalmic, inhaled, and nasal preparations. Dosing and duration depend on the indication and the patient’s response, and systemic steroids are typically tapered when discontinuing after extended use.

Safety and adverse effects are most prominent with systemic use and may include hyperglycemia, increased risk of infection, hypertension, fluid retention, mood changes, sleep disturbances, osteoporosis, skin thinning, and weight gain. The risk rises with higher doses and longer treatment. Contraindications include systemic fungal infections; caution is advised in diabetes, peptic ulcers, pregnancy, and in children. Monitoring and dose adjustments are recommended to minimize complications.

Pharmacokinetically, dexamethasone is a potent, long-acting glucocorticoid that is well absorbed orally, extensively protein-bound, metabolized in the liver (primarily by CYP3A4), and excreted in the urine.