What single oral dose of prednisolone should be given to a 21‑lb (≈9.5‑kg) child with croup?

Prednisolone Dosing for Croup in a 21-lb Child

Give prednisolone 1 mg/kg orally as a single dose, which equals approximately 9.5 mg (or 10 mg rounded) for this 21-lb (9.5-kg) child.

Dosing Rationale

The FDA-approved dosing for prednisolone in pediatric patients ranges from 0.14 to 2 mg/kg/day depending on the condition 1. For croup specifically, the standard dose used in clinical trials and practice is 1 mg/kg as a single oral dose 2, 3, 4.

For your 21-lb patient:

• Weight = 21 lbs ÷ 2.2 = 9.5 kg
• Dose = 1 mg/kg × 9.5 kg = 9.5 mg prednisolone
• Practical dose = 10 mg (rounded for ease of administration)

Evidence Supporting This Recommendation

Prednisolone vs. Dexamethasone Considerations:

While both corticosteroids are effective for croup, the evidence shows important differences:

• Acute symptom control: Prednisolone 1 mg/kg is non-inferior to dexamethasone for reducing croup scores at 1-6 hours post-treatment 2, 3. The 2019 PREDICT trial with 1,252 children demonstrated no clinically significant difference in Westley Croup Scores between prednisolone and dexamethasone 2.

• Re-presentation rates: Some studies suggest prednisolone may have higher re-attendance rates (29% vs 7% in one trial) 5, though the larger 2019 study found no significant difference (21.7% vs 17.8%, p=0.19) 2. The Cochrane review indicates dexamethasone probably reduces return visits by almost half compared to prednisolone 6.

Key Clinical Caveat: If you have concerns about compliance or re-presentation risk, dexamethasone 0.15-0.6 mg/kg may be preferable as it has a longer half-life and more consistent evidence for preventing return visits 6. However, prednisolone's advantage is its widespread availability in liquid formulation, making it practical for pediatric use 5.

Practical Administration Points

• Formulation: Prednisolone comes as oral solution (15 mg/5 mL is common) 1
• Timing: Single dose, no tapering needed for acute croup 1
• Follow-up: Consider advising a second dose the following day if symptoms persist, as some evidence suggests this may reduce re-presentation 7
• Alternative if unavailable: Dexamethasone 0.15 mg/kg (1.4 mg for this child) is equally effective and may have lower re-presentation rates 2, 6

When to Consider Higher Doses or Alternative Agents

The 1 mg/kg prednisolone dose is appropriate for mild to moderate croup. For severe croup with significant respiratory distress:

• Add nebulized epinephrine (0.5 mL/kg of 1:1000 solution, max 5 mL) 8
• Consider parenteral dexamethasone if unable to tolerate oral medication 9
• The standard prednisolone dose remains 1 mg/kg even in severe cases; higher doses are not indicated 1, 4