What is the recommended dose of dexamethasone (corticosteroid) in milligrams per kilogram (mg/kg) for a patient?

Dexamethasone mg/kg Dosing

The recommended dose of dexamethasone varies significantly by indication, ranging from 0.15 mg/kg every 6 hours for bacterial meningitis to 1 mg/kg/day for severe head injury, with most common indications using 0.3-0.6 mg/kg as a single or divided dose. 1, 2, 3

Indication-Specific Dosing Algorithms

Bacterial Meningitis (Pediatric and Adult)

• Pediatric patients: 0.15 mg/kg every 6 hours for 2-4 days 1, 2
• Adult patients: 0.15 mg/kg every 6 hours for 2-4 days (equivalent to 10 mg every 6 hours for a 67 kg adult) 1
• Critical timing requirement: Must administer the first dose 10-20 minutes before or at least concomitant with the first antimicrobial dose 1, 2
• Important caveat: Dexamethasone is completely ineffective if given after antimicrobial therapy has already begun 2

Acute Asthma Exacerbations (Pediatric)

• Single-dose regimen: 0.3 mg/kg orally as a single dose 4, 5, 6
• Alternative range: 0.3-0.6 mg/kg daily for 1-5 days 6
• Evidence strength: A randomized controlled trial demonstrated that single-dose dexamethasone 0.3 mg/kg is non-inferior to 3 days of prednisolone for acute asthma exacerbations 5
• Practical advantage: Zero vomiting episodes with dexamethasone versus 14 patients vomiting prednisolone in the trial 5

Severe Head Injury (Pediatric)

• High-dose regimen: 1 mg/kg/day for the first 3 days 7
• Major safety concern: This dose suppresses endogenous cortisol production for up to 6 days and increases risk of bacterial pneumonia (7/13 vs 2/12 patients) without improving outcomes 7
• Clinical recommendation: High-dose dexamethasone is not recommended for severe head injury based on this evidence 7

Acute Respiratory Distress Syndrome (ARDS)

• Fixed dosing (not weight-based): 20 mg IV once daily for days 1-5, then 10 mg IV once daily for days 6-10 8
• Evidence: Reduced ventilator-free days by 4.8 days and decreased 60-day mortality from 36% to 21% in moderate-to-severe ARDS 8
• Note: This is one of the few indications where fixed dosing rather than mg/kg dosing is used 8

Immune Effector Cell-Associated Neurotoxicity Syndrome (ICANS)

• Grade 2+ ICANS: 10 mg IV every 6-12 hours (not weight-based for adults) 1
• Grade 3-4 ICANS: Escalate to methylprednisolone 1,000 mg IV once or twice daily 1
• Pediatric consideration: For children, use 0.15 mg/kg dosing framework from meningitis guidelines 2

Glucocorticoid-Induced Hyperglycemia Management

• Context-specific: When dexamethasone is used for other indications (e.g., chemotherapy), insulin requirements are approximately 0.3 units/kg per day of isophane insulin, with 2/3 given in the morning and 1/3 in early evening 1

Route Equivalence: IV to Oral Conversion

Dexamethasone has 1:1 bioequivalence between IV and oral routes—no dose adjustment is needed when converting. 9

• 8 mg IV = 8 mg oral 9
• 12 mg IV = 12 mg oral 9
• 40 mg IV = 40 mg oral 9, 10
• This equivalence is consistently supported by ASCO and NCCN guidelines across multiple indications 9

Critical Safety Considerations

Neonatal and Preterm Infant Restrictions

• Avoid high-dose dexamethasone (≥0.5 mg/kg/day) in neonates due to risks of: 2
  • Gastrointestinal perforation
  • Hypertension and hyperglycemia
  • Impaired growth
  • Neurodevelopmental impairment

Administration Technique for IV Route

• Administer by slow IV infusion over several minutes 10
• If perineal burning occurs during IV push, slow or temporarily pause the infusion 10

Tapering Requirements

• Short courses (3-4 days): No taper typically needed for antiemetic or meningitis regimens 9
• Doses ≥8 mg/day for >5 days: 9
  • Reduce by 50% every 3-4 days until reaching 4 mg/day
  • Then reduce by 2 mg every 3-4 days until reaching 2 mg/day
  • Finally reduce by 1 mg every 3-4 days until discontinued
  • Monitor for withdrawal symptoms at each step

Common Pitfalls to Avoid

1. Do not confuse dexamethasone with other corticosteroids that have different oral-to-IV conversion ratios (e.g., hydrocortisone, methylprednisolone) 9

2. Do not use dexamethasone for streptococcal pharyngitis—use acetaminophen or NSAIDs instead 2

3. Do not assume higher doses are better—the 1 mg/kg/day dose for head injury increased infections without improving outcomes 7

4. Do not delay antimicrobials to give dexamethasone first in meningitis—they should be given together if the 10-20 minute window cannot be achieved 1

5. Do not use preservative-containing solutions in neonates, especially premature infants 3