Oral Prednisone Dose for Croup When Dexamethasone Is Unavailable
Give oral prednisone 1 mg/kg as a single dose (maximum 60 mg) to children aged 6 months to 5 years with croup when dexamethasone is unavailable, but be aware that this is less effective than dexamethasone and carries a significantly higher risk of unscheduled return to medical care. 1
Why Dexamethasone Is Preferred Over Prednisone
The evidence strongly favors dexamethasone as the corticosteroid of choice for croup. A head-to-head randomized controlled trial demonstrated that children treated with prednisolone 1 mg/kg had a 29% re-presentation rate compared to only 7% with dexamethasone 0.15 mg/kg—a clinically significant 22% absolute difference. 1 This means nearly 1 in 3 children given prednisolone will require additional medical care, compared to fewer than 1 in 14 given dexamethasone. 1
A more recent community-based trial using prednisolone 2 mg/kg/day for 3 days (versus single-dose dexamethasone 0.6 mg/kg) found no significant differences in outcomes, but this study used a multi-day prednisolone regimen rather than the single-dose approach. 2 The single-dose prednisolone regimen remains inferior based on the strongest available evidence. 1
Specific Dosing When Prednisone Must Be Used
- Dose: 1 mg/kg as a single oral dose 3, 1, 4
- Maximum dose: 60 mg regardless of weight 5, 6
- Timing: Give as soon as possible after diagnosis 3
- Formulation: Use liquid prednisolone if available, as it is more readily absorbed than tablets—particularly important in children who may vomit or have difficulty swallowing 3
- No taper needed: Single-dose or courses under 7 days require no tapering 3, 5
Practical Example
For a 14 kg child with croup: give prednisolone 14 mg as a single oral dose. 3
Alternative Dosing Considerations From Older Literature
Older evidence suggests that prednisolone 1 mg/kg every 12 hours may be effective for severe croup requiring intubation, where it decreases duration of intubation and need for reintubation. 4 However, this applies to intubated patients in intensive care settings, not the typical outpatient or emergency department presentation. 4
Critical Clinical Pitfalls
- Higher failure rate: Counsel families that return visits are more likely with prednisone than dexamethasone, and provide clear return precautions for worsening stridor, retractions, or respiratory distress 1
- Not equivalent despite similar pharmacokinetics: Although prednisolone and dexamethasone have similar anti-inflammatory properties, the clinical outcomes differ substantially in croup 1
- Liquid formulation matters: Tablets may not be adequately absorbed in a child with croup who is drooling or has difficulty swallowing 3
- Single-dose compliance advantage lost: One benefit of dexamethasone is eliminating multi-day compliance issues; using prednisone negates this advantage while still delivering inferior outcomes 3, 1
When to Use Nebulized Epinephrine
For severe croup with significant respiratory distress (marked stridor at rest, retractions, agitation), nebulized epinephrine remains first-line therapy alongside corticosteroids: give 0.5 mL/kg of 1:1000 solution (maximum 5 mL) by nebulizer. 3 Corticosteroids are adjunctive in severe cases but primary therapy in mild-to-moderate croup. 3, 4
Safety Profile
Single-dose corticosteroids for croup carry minimal risk. 4 The only potentially significant adverse effect is increased risk of severe varicella infection in exposed children, though this is rare. 4 Single-dose dexamethasone does not cause clinically significant adrenal suppression or hypothalamic-pituitary-adrenal axis suppression in children with croup. 7