What is the pediatric dose of Decadron (dexamethasone) for a 40 lb child?

Pediatric Dexamethasone Dosing for a 40 lb Child

For a 40 lb (18 kg) child, the appropriate dose of dexamethasone depends entirely on the clinical indication, with doses ranging from 0.15 mg/kg for adrenal insufficiency to 0.6 mg/kg for croup.

Weight Conversion

• 40 lb = 18.2 kg 1

Dosing by Clinical Indication

Croup (Most Common Pediatric Use)

• Dose: 0.6 mg/kg orally = 10.9 mg (approximately 11 mg) as a single dose 2
• This is the most effective route and dose for mild to moderate croup, showing superior outcomes compared to nebulized dexamethasone or placebo 2
• Children receiving oral dexamethasone demonstrate more rapid symptom resolution and are less likely to seek additional medical care 2

Acute Asthma Exacerbation

• Dose: 0.3 mg/kg orally = 5.5 mg (approximately 6 mg) as a single dose 3, 4
• This single dose is noninferior to a 3-day course of prednisolone (1 mg/kg/day) for acute asthma exacerbations 4
• The advantage is improved compliance by eliminating multi-day dosing 3, 4
• Important caveat: Approximately 13% of children may require additional systemic steroids within 14 days, compared to 4% with prednisolone, so close follow-up is essential 4

Adrenal Insufficiency (Emergency Setting)

• Initial dose: 2-3 mg/kg IV/IO = 36-55 mg (maximum 100 mg) over 3-5 minutes 1
• Maintenance: 1-5 mg/kg every 6 hours for infants 1
• Critical point: Do not underdose in suspected adrenal crisis 1
• Strongly consider concomitant fluid bolus of 20 mL/kg of D5NS or D10NS during the first hour 1

Key Clinical Considerations

Route Selection

• Oral route is preferred when the child can tolerate it and the condition allows (croup, asthma) 4, 2
• IV/IO route is mandatory for adrenal insufficiency or when the child cannot take oral medications 1

Common Pitfalls to Avoid

• Do not use high-dose dexamethasone in extremely premature infants (birth weight 501-1000 g), as early administration is associated with gastrointestinal perforation, decreased growth, and no improvement in chronic lung disease outcomes 5
• Do not underdose in adrenal crisis, as this can be life-threatening 1
• Monitor for vomiting with oral administration; dexamethasone has lower vomiting rates than prednisolone 4

Follow-up Requirements

• For asthma exacerbations treated with single-dose dexamethasone, ensure close follow-up within 4-7 days, as some children may require additional steroids 4
• For croup, telephone follow-up on days 1,2,3,4, and 7 helps identify treatment failures early 2