Overview
Dexamethasone is a potent synthetic glucocorticoid with anti-inflammatory and immunosuppressive properties. It is used to treat a wide range of conditions including inflammatory disorders, allergic reactions, autoimmune diseases, and cerebral edema. The drug is available in various formulations including injectable solutions for parenteral administration when oral therapy is not feasible.
Mechanism of Action
Dexamethasone binds to glucocorticoid receptors, modulating gene expression to inhibit inflammatory mediators (cytokines, chemokines, adhesion molecules), suppress immune cell function, and stabilize cell membranes. It has minimal mineralocorticoid activity compared to other corticosteroids.
Indications
- Adrenocortical insufficiency (as adjunct to mineralocorticoids)
- Rheumatic disorders (rheumatoid arthritis, osteoarthritis, bursitis, gout)
- Collagen diseases (systemic lupus erythematosus, rheumatic carditis)
- Dermatologic conditions (pemphigus, severe psoriasis, exfoliative dermatitis)
- Allergic states (asthma, allergic rhinitis, drug hypersensitivity)
- Ophthalmic inflammatory diseases (uveitis, optic neuritis, keratitis)
- Gastrointestinal diseases (ulcerative colitis, Crohn's disease)
- Respiratory conditions (sarcoidosis, aspiration pneumonitis)
- Hematologic disorders (autoimmune hemolytic anemia, ITP)
- Cerebral edema
- Multiple sclerosis exacerbations
- Nephrotic syndrome
- Palliative management of leukemias and lymphomas
Common Doses
- 4 mg/mL injection
- 10 mg/mL injection
- Typical doses: 0.5-9 mg daily depending on indication
Dosage
Initial dosage varies from 0.5-9 mg/day depending on condition, typically one-third to one-half oral dose given every 12 hours. For cerebral edema: 10 mg IV initially, then 4 mg IM every 6 hours. For shock: 1-6 mg/kg IV as single dose or 40 mg initially with repeat doses. Intra-articular doses: 2-4 mg for large joints, 0.8-1 mg for small joints. Dosage must be individualized and tapered gradually when discontinuing long-term therapy.
Contraindications
- Systemic fungal infections
- Known hypersensitivity to dexamethasone or components
- Live virus vaccinations in immunocompromised patients
- Intrathecal administration
Side Effects
- Fluid/electrolyte disturbances: sodium retention, hypokalemia, hypertension
- Musculoskeletal: osteoporosis, fractures, avascular necrosis, myopathy
- Gastrointestinal: peptic ulcer, pancreatitis, abdominal distention
- Dermatological: impaired wound healing, thin skin, bruising
- Neurological: increased intracranial pressure, headache, vertigo
- Ophthalmic: cataracts, glaucoma
- Endocrine: Cushing's syndrome, growth suppression, diabetes
- Metabolic: negative nitrogen balance, hyperglycemia
- Immunological: increased infection susceptibility
- Injection site reactions: flare, atrophy, sterile abscess
Interactions
- Anticoagulants: altered response
- Antidiabetic agents: increased insulin requirements
- Enzyme inducers (phenytoin, rifampin): reduced corticosteroid effect
- Enzyme inhibitors (ketoconazole): increased corticosteroid effect
- NSAIDs: increased GI ulcer risk
- Diuretics: enhanced potassium loss
- Live vaccines: reduced efficacy, potential infection
Counseling Points
- Do not stop medication abruptly - requires gradual tapering
- Report signs of infection (fever, sore throat)
- Monitor for weight gain, swelling, mood changes
- Avoid exposure to infections, especially chickenpox/measles
- Inform all healthcare providers of corticosteroid use
- Carry medical identification indicating steroid use
- Regular eye exams recommended with prolonged use
- Report severe abdominal pain or black stools
- Caution with alcohol and NSAIDs due to GI risk
- Follow-up for bone density monitoring with long-term use