Dexamethasone Dosing for a 20 kg Child
For a 20 kg child, the recommended dose of dexamethasone is 0.15 mg/kg, which equals 3 mg as a single dose.
Dosage Calculation
The appropriate dosing of dexamethasone depends on the clinical indication, but generally follows these principles:
- Standard dose: 0.15 mg/kg × 20 kg = 3 mg
- This dosage is supported by multiple guidelines and clinical studies as being effective while minimizing adverse effects 1
- Maximum recommended single dose for most pediatric indications: 0.6 mg/kg (which would be 12 mg for a 20 kg child, but this higher dose is rarely needed and carries increased risk of side effects)
Indication-Specific Dosing
Acute Conditions
- Croup: 0.15 mg/kg (3 mg) as a single oral or parenteral dose 2, 3
- Research has shown that 0.15 mg/kg is as effective as higher doses (0.3 mg/kg or 0.6 mg/kg) with fewer side effects
- Benefits may be seen as early as 30 minutes after administration 4
Severe Allergic Reactions/Contact Dermatitis
- Severe cases: 0.15 mg/kg (3 mg) as a single dose 1
- Follow-up: Close monitoring within 24-48 hours
Antiemetic Use
- For post-operative nausea/vomiting: 0.15 mg/kg (3 mg) every 12 hours 5
- For chemotherapy-induced nausea: Dosing may need adjustment based on protocol
Administration Routes
- Oral: Preferred when possible
- Intravenous: For urgent situations or when oral route not available
- Intramuscular: Alternative when IV access is unavailable
- Topical: Not relevant for systemic effects (used only for local inflammation)
Safety Considerations
Potential Adverse Effects
- Short-term: Hyperglycemia, hypertension, mood changes, increased appetite
- Long-term: Growth suppression, adrenal suppression, increased infection risk
Important Precautions
- Avoid prolonged use in pediatric patients due to potential neurodevelopmental effects 5, 6
- Monitor blood pressure, blood glucose, and growth parameters during treatment
- Contraindicated in systemic fungal infections or known hypersensitivity 1
- Use with caution in patients with diabetes as it may affect glucose control
Alternative Considerations
For certain conditions, especially in neonates or prolonged therapy, hydrocortisone may be preferred over dexamethasone due to:
- Lower risk of neurodevelopmental impairment 5
- Different receptor binding profile (binds to both mineralocorticoid and glucocorticoid receptors) 5
- Shorter half-life allowing more physiologic dosing
Dosing Pitfalls to Avoid
- Overdosing: Using the higher dose (0.6 mg/kg) when the lower dose (0.15 mg/kg) is equally effective
- Prolonged therapy: Continuing dexamethasone longer than necessary increases risk of adverse effects
- Abrupt discontinuation: For courses longer than a few days, consider tapering to avoid adrenal insufficiency
- Failure to adjust for body weight: Always calculate based on current weight, not age or estimated weight
Remember that while 0.15 mg/kg (3 mg for a 20 kg child) is appropriate for most indications, the specific clinical scenario may warrant adjustments to this recommendation.