Dexamethasone exerts its effects by binding to intracellular glucocorticoid receptors, which then translocate to the nucleus and modulate gene transcription. This results in:

1. Anti-inflammatory Effects: Dexamethasone inhibits the production of pro-inflammatory cytokines (e.g., IL-1, IL-6, TNF-α) and chemokines, reduces the migration of inflammatory cells to sites of inflammation, and stabilizes lysosomal membranes.
2. Immunosuppressive Effects: It suppresses the activity of T-cells, B-cells, and macrophages, reducing the immune response.
3. Metabolic Effects: Dexamethasone increases gluconeogenesis, reduces glucose uptake by cells, and promotes protein catabolism and lipolysis.
4. Endocrine Effects: It suppresses the hypothalamic-pituitary-adrenal (HPA) axis, reducing the production of endogenous cortisol.

Dexamethasone is used in a wide range of clinical conditions, including:

1. Inflammatory and Autoimmune Disorders:
   • Rheumatoid arthritis
   • Systemic lupus erythematosus
   • Asthma exacerbations
   • Allergic reactions
   • Inflammatory bowel disease (e.g., Crohn's disease, ulcerative colitis)
2. Endocrine Disorders:
   • Adrenal insufficiency (as replacement therapy)
   • Congenital adrenal hyperplasia
3. Oncology:
   • Management of chemotherapy-induced nausea and vomiting
   • Reduction of cerebral edema in brain tumors
   • Palliative treatment in certain cancers (e.g., multiple myeloma, lymphoma)
4. Neurology:
   • Treatment of acute exacerbations of multiple sclerosis
   • Management of cerebral edema
5. Other Uses:
   • Prevention of neonatal respiratory distress syndrome (antenatal use)
   • Treatment of croup in children
   • Management of septic shock (controversial, but sometimes used)

The dosage of dexamethasone varies depending on the condition being treated, the route of administration, and patient-specific factors. Below are general guidelines:

1. Oral/Intravenous/Intramuscular:
   • Adults: 0.5–10 mg daily, depending on the condition. Higher doses may be used in acute conditions (e.g., cerebral edema: 10 mg initially, followed by 4 mg every 6 hours).
   • Children: 0.02–0.3 mg/kg/day in divided doses.
2. Topical/Ophthalmic:
   • Applied as directed, typically 1–2 times daily.
3. Special Populations:
   • Elderly: Lower doses may be required due to increased risk of side effects.

Renal/Hepatic Impairment: Dose adjustment may be necessary

Dexamethasone is generally well-tolerated when used short-term, but prolonged use can lead to significant side effects. These include:

1. Common Side Effects:
   • Increased appetite and weight gain
   • Insomnia
   • Mood changes (e.g., anxiety, depression)
   • Gastrointestinal disturbances (e.g., nausea, peptic ulcers)
2. Serious Side Effects:
   • Endocrine: Adrenal suppression, Cushing's syndrome, hyperglycemia.
   • Cardiovascular: Hypertension, fluid retention.
   • Musculoskeletal: Osteoporosis, muscle weakness.
   • Ophthalmic: Cataracts, glaucoma.
   • Infections: Increased susceptibility to infections due to immunosuppression.

1. Contraindications:
   • Systemic fungal infections
   • Hypersensitivity to dexamethasone or other corticosteroids
2. Warnings:
   • Use with caution in patients with diabetes, hypertension, peptic ulcer disease, osteoporosis, or psychiatric disorders.
   • Avoid abrupt discontinuation after prolonged use to prevent adrenal crisis.
3. Monitoring:
   • Blood glucose levels
   • Blood pressure
   • Bone density (in long-term use)
   • Signs of infection

Dexamethasone interacts with several medications, including:

1. Anticoagulants (e.g., warfarin): Increased risk of bleeding.
2. Antidiabetic Agents: Reduced efficacy due to hyperglycemia.
3. NSAIDs (e.g., ibuprofen): Increased risk of gastrointestinal bleeding.
4. Vaccines: Reduced immune response to live vaccines.
5. Enzyme Inducers (e.g., phenytoin, rifampin): Reduced dexamethasone levels.

Potassium-Depleting Drugs (e.g., diuretics): Increased risk of hypokalemia

Dexamethasone is available under various generic names and brand names worldwide. Some common generic names include:

• Dexamethasone sodium phosphate
• Dexamethasone acetate
• Dexamethasone base

Brand names vary by region and formulation (e.g., Decadron, Dexasone, Hexadrol).