What is the appropriate dexamethasone dose for a 36‑lb (≈16‑kg) child with croup?

Dexamethasone Dosing for Croup in a 36-Pound Child

Give 0.6 mg/kg of dexamethasone (approximately 9.6 mg for this 16-kg child), administered orally if the child can tolerate it, with a maximum dose of 16 mg. 1, 2

Standard Dosing Recommendation

• The American Academy of Pediatrics recommends a single dose of dexamethasone 0.6 mg/kg (maximum 16 mg) for pediatric croup, given orally, intramuscularly, or intravenously. 1, 2
• For a 36-pound (16.3 kg) child, this calculates to approximately 9.8 mg, well below the 16 mg maximum. 1
• Oral administration is strongly preferred when the child can tolerate it, as it is equally effective as intramuscular or intravenous routes and avoids injection pain. 2

Lower-Dose Alternative

• A lower dose of 0.15 mg/kg may achieve comparable clinical improvement (approximately 2.4 mg for this child) and could reduce potential side effects. 2
• Multiple high-quality RCTs demonstrate that 0.15 mg/kg is as effective as 0.6 mg/kg for moderate-to-severe croup, with similar hospitalization duration, croup score reduction, and need for additional treatments. 3, 4, 5
• The benefit of 0.15 mg/kg dexamethasone is observable as early as 30 minutes after administration. 2, 6

Clinical Decision Algorithm

For mild croup (minimal stridor at rest, no retractions):

• Consider 0.15 mg/kg dexamethasone orally to minimize side effects while maintaining efficacy. 2, 4

For moderate-to-severe croup (prominent stridor at rest, retractions, agitation):

• Give 0.6 mg/kg dexamethasone orally (or IM/IV if unable to tolerate oral). 1, 2
• Add nebulized epinephrine 0.5 mL/kg of 1:1000 solution (maximum 5 mL) for significant respiratory distress while waiting for dexamethasone to take effect. 7, 2
• If severe stridor persists despite initial treatment, administer a repeat dexamethasone dose plus nebulized epinephrine. 1, 2

Route Selection

• All three routes (oral, IM, IV) are equally effective for croup treatment. 1
• Use intramuscular dexamethasone only for children who are vomiting or in severe respiratory distress unable to tolerate oral medication. 8
• Intravenous administration is reserved for children requiring IV access for other reasons or those unable to take oral/IM routes. 1

Duration and Repeat Dosing

• The therapeutic effect lasts 24-72 hours from a single dose and does not require tapering; adrenal suppression is minimal. 1, 2
• Onset of action begins as early as 30 minutes, with statistically significant improvement by 30 minutes and progressive benefit through 12 hours. 2, 6
• Most children require only one dose; repeat dosing is indicated only for severe, persistent symptoms. 1, 2

Important Caveats

• Do not use dexamethasone for non-specific cough, chronic cough, or pertussis-associated cough, as it provides no benefit in these conditions. 1, 2
• Prednisolone is less effective than dexamethasone for croup, with 29% re-presentation to medical care compared to 7% with dexamethasone. 1, 2
• Nebulized corticosteroids from hand-held inhalers with spacers are ineffective for croup and should not be used. 1, 2
• Nebulized budesonide is equally effective as oral dexamethasone but is less practical in most settings. 1