Dexamethasone Dosing for a 20-Month-Old Child
For a 20-month-old child, the appropriate oral dexamethasone dose is 0.6 mg/kg (maximum 16 mg) as a single dose for croup, which is the most common indication in this age group. 1
Indication-Specific Dosing
The correct dexamethasone dose depends entirely on the clinical indication:
Croup (Most Common in This Age Group)
- Single dose of 0.6 mg/kg orally (maximum 16 mg) 1, 2
- Oral administration is preferred when the child can tolerate it, as it is equally effective as intramuscular or intravenous routes while avoiding injection pain 2
- Clinical effect begins as early as 30 minutes after administration, with duration of action lasting 24-72 hours 2, 3
- Research demonstrates that even lower doses (0.15 mg/kg) show benefit by 30 minutes, though the standard recommended dose remains 0.6 mg/kg 3, 4
- For severe respiratory distress, adjunctive nebulized epinephrine (0.5 mL/kg of 1:1000 solution, maximum 5 mL) can be added while waiting for dexamethasone to take effect 1
Bacterial Meningitis
- 0.15 mg/kg orally every 6 hours for 2-4 days 1, 5
- Must be initiated 10-20 minutes prior to, or at least concomitant with, the first antimicrobial dose 1, 5
- Critical caveat: Dexamethasone is ineffective if antimicrobial therapy has already begun 5
Asthma Exacerbations
- Single dose of 0.6 mg/kg orally (maximum 16 mg) 1
- This single dose is equally effective as a 3-5 day course of prednisolone or prednisone 1
Important Safety Considerations
Avoid High-Dose Regimens in Young Children
- High-dose dexamethasone (≥0.5 mg/kg/day) should be avoided in neonates and preterm infants due to risk of gastrointestinal perforation, hypertension, hyperglycemia, impaired growth, and neurodevelopmental impairment 5, 6
- The American Academy of Pediatrics specifically warns against high daily doses (approximately 0.5 mg/kg per day) due to associations with neurodevelopmental impairment 7
Single-Dose Safety Profile
- A single short course does not cause clinically significant adrenal suppression and does not require tapering 2, 5
- Common side effects include gastric irritation, behavioral changes, weight gain, and increased appetite 1
Clinical Pitfalls to Avoid
- Do not use dexamethasone for streptococcal pharyngitis - acetaminophen or NSAIDs should be used instead 5
- Do not delay treatment in croup - benefit begins within 30 minutes, much earlier than previously thought 3
- Do not use nebulized corticosteroids from hand-held inhalers with spacers - they are ineffective for croup 2
- Do not give dexamethasone for bacterial meningitis after antibiotics have started - it becomes ineffective 5