Dexamethasone Administration for Croup
Give a single dose of dexamethasone 0.6 mg/kg (maximum 16 mg) orally, intramuscularly, or intravenously—oral route is preferred when the child can tolerate it. 1
Dosing Recommendations
Standard dose is 0.6 mg/kg with a maximum cap of 16 mg, regardless of the child's weight (e.g., a 38 kg child would calculate to 22.8 mg but receives only the 16 mg maximum). 1
Lower doses (0.15 mg/kg) may be equally effective based on research evidence, though the guideline-recommended dose remains 0.6 mg/kg. 2, 3, 4 The 0.15 mg/kg dose showed equivalent outcomes in hospitalization duration, croup score reduction, and need for additional treatments in multiple trials. 2, 3
Route of Administration
Oral administration is the preferred route due to ease of use, availability, low cost, and avoidance of injection pain—it has equivalent bioavailability to IV administration (1:1 conversion). 5, 1
All three routes (oral, IM, IV) are equally effective for treating croup. 1
When using IV administration, infuse slowly over several minutes to prevent perineal burning; if burning occurs, slow or pause the infusion temporarily. 5
Onset and Duration of Action
Symptom improvement begins as early as 30 minutes after administration, with statistically significant benefit evident by 30 minutes in mild-to-moderate croup. 1, 6
Clinical duration of action is approximately 24-72 hours, providing sustained relief from a single dose. 1
No tapering is required for the single-dose regimen used in croup, and it does not cause significant adrenal suppression. 1
Adjunctive Therapy for Moderate-to-Severe Croup
For significant respiratory distress (prominent stridor, significant retractions, agitation), add nebulized epinephrine at 0.5 mL/kg of 1:1000 solution (maximum 5 mL) while waiting for dexamethasone to take effect. 5, 1
Epinephrine provides immediate but short-term symptom improvement, while dexamethasone provides longer-lasting relief. 1
Repeat Dosing Considerations
For severe croup with prominent stridor, significant retractions, and agitation, administer a repeat dexamethasone dose plus nebulized epinephrine, regardless of timing of the initial dose. 1
Children requiring two epinephrine treatments should be hospitalized. 7
Important Clinical Pitfalls
Do not use nebulized corticosteroids from hand-held inhalers with spacers—they are ineffective for croup. 1
Nebulized budesonide (500 µg) is an alternative that may reduce symptoms in the first 2 hours, but is less commonly used than oral dexamethasone due to convenience and cost factors. 5
For intubated patients, administer dexamethasone at least 6 hours before anticipated extubation to prevent upper airway obstruction. 1