Dexamethasone Dosing for a 3-Year-Old Weighing 34 Pounds
For a 3-year-old weighing 34 pounds (15.4 kg), administer dexamethasone 0.6 mg/kg (9.2 mg) as a single oral dose for croup or asthma exacerbation, which are the most common indications requiring dexamethasone in this age group. 1
Indication-Specific Dosing
The appropriate dexamethasone dose depends entirely on the clinical indication:
Croup (Most Common Indication)
- Administer 0.6 mg/kg (9.2 mg for this patient) as a single dose 1
- Maximum dose is 16 mg 1
- Oral administration is preferred when the child can tolerate it, as it is equally effective as intramuscular or intravenous routes and avoids injection pain 1
- Clinical benefit begins as early as 30 minutes after administration, with duration of action lasting 24-72 hours 1, 2
- For severe respiratory distress, add nebulized epinephrine (0.5 mL/kg of 1:1000 solution, maximum 5 mL) while waiting for dexamethasone to take effect 1
Asthma Exacerbation
- Use the same dose: 0.6 mg/kg (9.2 mg) as a single dose 1
- This single dose is equally effective as a 3-5 day course of prednisolone or prednisone 1
- Maximum dose is 16 mg 1
Bacterial Meningitis
- Administer 0.15 mg/kg (2.3 mg for this patient) every 6 hours for 2-4 days 1
- Must be initiated 10-20 minutes prior to, or at least concomitant with, the first antimicrobial dose 1
- Do not give if antimicrobial therapy has already been started 1
Critical Dosing Considerations
Weight-based dosing is appropriate for this patient. The child weighs 15.4 kg, which falls within the normal range for a 3-year-old, so standard weight-based calculations apply without adjustment 3, 4.
Common Pitfalls to Avoid
- Do not use high-dose dexamethasone (0.5 mg/kg/day) for any indication in this age group unless treating acute lymphoblastic leukemia under oncology supervision, as high doses are linked to adverse neurodevelopmental outcomes 5, 1
- Do not prescribe multiple doses for croup or asthma - a single dose is sufficient and equally effective 1, 6
- Do not delay administration - clinical benefit begins within 30 minutes for croup 1, 2
Route of Administration
- Oral and IV dexamethasone are bioequivalent with 1:1 conversion 7, 8
- Choose oral route when possible to avoid injection pain and achieve equivalent efficacy 1
- If giving IV, administer by slow infusion over several minutes to avoid perineal burning 8
Age-Specific Considerations
For this 3-year-old patient, standard weight-based dosing (0.6 mg/kg for croup/asthma) is appropriate without age-related dose adjustments 1. Age-related dose reductions are only necessary for infants under 3 months or children over 6 years when targeting specific exposure levels 4.