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Sunday, July 27, 2025

Dexamethasone tablets and liquid


Dexamethasone is a synthetic long-acting glucocorticoid (corticosteroid) with potent anti-inflammatory and immunosuppressive properties. It is available in various formulations, including oral tablets and liquid (elixir/syrup), and is used across a wide range of medical conditions including severe allergic reactions, inflammation, cerebral edema, autoimmune diseases, cancers, and specific endocrine disorders. Oral dexamethasone is frequently used when systemic corticosteroid therapy is required.

Pharmacological Classification

  • Therapeutic class: Systemic corticosteroid

  • Pharmacological class: Glucocorticoid

  • ATC code: H02AB02

  • Controlled status: Prescription-only medicine (Rx)

Mechanism of Action

Dexamethasone binds to cytoplasmic glucocorticoid receptors, translocates to the nucleus, and modulates gene transcription, resulting in:

  • Suppression of pro-inflammatory cytokines (e.g., IL-1, IL-6, TNF-α)

  • Inhibition of leukocyte infiltration and function

  • Reduction in capillary permeability

  • Inhibition of phospholipase A2, reducing prostaglandins and leukotrienes

  • Decreased immune response, particularly T-cell mediated

It has minimal mineralocorticoid activity, unlike hydrocortisone or prednisolone, making it more suitable in conditions where fluid retention is undesirable.

Formulations

Oral Forms

  • Tablets: 0.5 mg, 2 mg, 4 mg, 6 mg (most commonly used)

  • Oral liquid: 0.5 mg/5 mL or 1 mg/mL (varies by country and manufacturer)

    • Available as syrup or elixir for pediatric and geriatric use

Pharmacokinetics

  • Bioavailability: ~80–90% (oral)

  • Onset of action: ~1 hour (oral)

  • Half-life: 36–54 hours (biological effect), 4–5 hours (plasma)

  • Metabolism: Hepatic (CYP3A4)

  • Excretion: Renal

Indications

Immunologic and Inflammatory

  • Severe allergic reactions (e.g., angioedema, anaphylaxis adjunct)

  • Asthma exacerbations

  • Chronic obstructive pulmonary disease (COPD) exacerbations

  • Autoimmune diseases (e.g., systemic lupus erythematosus, vasculitis)

Oncology

  • Cerebral edema due to brain tumors

  • Part of chemotherapy regimens (e.g., for leukemia, lymphoma, multiple myeloma)

  • Anti-emetic adjunct in chemotherapy

Endocrine Disorders

  • Adrenal insufficiency (e.g., Addison's disease, secondary adrenal suppression)

  • Congenital adrenal hyperplasia

  • Dexamethasone suppression test (for diagnosing Cushing’s syndrome)

Infectious and Inflammatory Neurology

  • Bacterial meningitis (as adjunctive therapy)

  • Cerebral tuberculosis (with antitubercular therapy)

  • COVID-19 pneumonia (severe) – oral dexamethasone has been widely used as per RECOVERY trial

Other Uses

  • Rheumatologic diseases (e.g., polymyalgia rheumatica, rheumatoid arthritis)

  • Organ transplantation (as part of immunosuppressive regimens)

  • Dermatologic conditions (severe eczema, pemphigus)

  • Palliative care for anorexia, nausea, dyspnea

Dosing Guidelines

Doses vary widely depending on the condition, severity, patient age, and duration of therapy. Dexamethasone is typically more potent than other corticosteroids:

  • 0.75 mg dexamethasone ≈ 5 mg prednisolone ≈ 20 mg hydrocortisone

General Adult Oral Doses

  • Anti-inflammatory/Immunosuppressive: 0.5–10 mg/day, in single or divided doses

  • Cerebral edema: 10–16 mg/day in divided doses; taper as needed

  • COVID-19 (hospitalized patients needing oxygen): 6 mg once daily for up to 10 days

  • Chemotherapy-induced nausea: 8–20 mg prior to chemo, followed by taper over days

Pediatric Doses

  • Generally based on weight or body surface area

  • Typical dose: 0.02–0.3 mg/kg/day

  • Requires specialist guidance and frequent monitoring

Contraindications

  • Systemic fungal infections

  • Hypersensitivity to dexamethasone or other corticosteroids

  • Concurrent live or live-attenuated vaccines in immunosuppressed individuals

  • Untreated active tuberculosis or ocular herpes simplex (use only with anti-TB therapy)

Precautions and Monitoring

Short-Term Use

  • Can lead to hyperglycemia, mood changes, and fluid retention

  • Use with caution in hypertensive or diabetic patients

  • Monitor for signs of superinfection or masked infections

Long-Term Use

  • HPA axis suppression

  • Osteoporosis (consider calcium and vitamin D supplementation)

  • Adrenal insufficiency on withdrawal – requires gradual tapering

  • Cushingoid features: moon face, weight gain, truncal obesity

  • Cataracts and glaucoma with long-term use

Special Caution In

  • Children (growth suppression)

  • Elderly (osteoporosis risk, psychosis)

  • Psychiatric illness (mania, psychosis)

  • Peptic ulcer disease

  • Uncontrolled diabetes mellitus

  • Liver cirrhosis

Adverse Effects

Common (1–10%)

  • Insomnia

  • Increased appetite and weight gain

  • Mood swings

  • Indigestion

  • Hyperglycemia

  • Headache

Serious or Long-Term

  • Hypertension

  • Osteoporosis and fractures

  • Adrenal suppression

  • Peptic ulcer or GI bleeding

  • Psychiatric effects (mania, depression, psychosis)

  • Cataracts and glaucoma

  • Myopathy

  • Opportunistic infections

Drug Interactions

Increased Risk of Hypokalemia

  • Diuretics (e.g., furosemide, thiazides)

  • Amphotericin B

  • Beta-2 agonists (e.g., salbutamol)

Reduced Efficacy of Dexamethasone

  • CYP3A4 inducers (e.g., rifampin, phenytoin, carbamazepine)

  • Barbiturates

Increased Dexamethasone Toxicity

  • CYP3A4 inhibitors (e.g., ketoconazole, erythromycin, diltiazem)

Vaccines

  • May reduce response to live and inactivated vaccines

  • Avoid live vaccines in immunosuppressed patients

Antidiabetic agents

  • Dexamethasone may antagonize effects of insulin or oral hypoglycemics

Comparison with Other Corticosteroids (No Tables)

Dexamethasone vs. Prednisolone

  • Dexamethasone is 25x more potent and longer-acting

  • Prednisolone has more mineralocorticoid activity

  • Dexamethasone used when fluid retention is to be avoided

  • Prednisolone is preferred for replacement therapy in adrenal insufficiency

Dexamethasone vs. Hydrocortisone

  • Hydrocortisone is short-acting, used for acute adrenal crisis

  • Dexamethasone is more appropriate for chronic inflammatory control

Dexamethasone vs. Methylprednisolone

  • Both are potent; methylprednisolone preferred in pulse therapy (e.g., multiple sclerosis flares)

  • Dexamethasone used more in oncology, neurology, and COVID-19

Use in Special Populations

Pregnancy

  • Crosses placenta; may affect fetal development (especially in early pregnancy)

  • Short courses may be used under medical supervision

  • Often used antenatally to accelerate fetal lung maturity in preterm labor

Lactation

  • Excreted in breast milk in small amounts

  • Short-term use generally considered compatible with breastfeeding

Pediatrics

  • Risk of growth suppression

  • Use lowest effective dose and monitor growth and development closely

Elderly

  • Increased risk of osteoporosis, glucose intolerance, neuropsychiatric effects

  • Use with caution and regular monitoring

Withdrawal and Tapering

Abrupt cessation after prolonged use can cause acute adrenal insufficiency, which is potentially life-threatening.

Symptoms of Withdrawal

  • Fatigue

  • Weakness

  • Nausea

  • Hypotension

  • Joint pain

  • Fever

Tapering schedule should be individualized and may span weeks to months, depending on duration and dose of prior therapy.

Patient Counseling Points

  • Take with food to reduce stomach irritation

  • Do not stop suddenly if taken for more than a few days—follow doctor's tapering plan

  • Report signs of infection, mood changes, vision changes, or unusual weight gain

  • Monitor blood sugar, especially if diabetic

  • Use calcium and vitamin D supplements if prescribed for long-term therapy

  • Keep all follow-up appointments for blood pressure, bone health, and lab tests

  • Store at room temperature, away from light and moisture

  • Keep out of reach of children




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