What are the recommended injectable hydrocortisone dosages for acute adrenal crisis, stress dosing, and routine replacement?

Injectable Hydrocortisone Dosing

For acute adrenal crisis in adults, give 100 mg hydrocortisone IV immediately, followed by 200 mg/24 hours via continuous IV infusion or divided every 6 hours; in children, give 50 mg/m² IV bolus followed by 50-100 mg/m²/day. 1

Acute Adrenal Crisis

The most critical scenario requiring immediate action:

Adults

• Initial bolus: 100 mg hydrocortisone IV push over 30 seconds to 10 minutes 2
• Maintenance: 200 mg/24 hours, administered either as:
  • Continuous IV infusion (preferred method) 3, OR
  • 50 mg IV/IM every 6 hours 1
• Fluid resuscitation: Rapid infusion of 1000 mL isotonic saline within first hour 1
• Duration: Continue until crisis resolves, typically 24-48 hours, then taper to 100 mg/day before switching to oral 1

Children

• Initial bolus: 50 mg/m² IV (practical doses: infants 25 mg, school-age 50 mg, adolescents 100 mg) 1
• Maintenance: 50-100 mg/m²/day divided every 6 hours 1
• Fluid resuscitation: 20 mL/kg normal saline bolus, can repeat up to 60 mL/kg total 1

Critical point: The 2020 pharmacokinetic study 3 demonstrated that continuous IV infusion is superior to bolus dosing for maintaining cortisol levels in the stress range, though the 2016 Endocrine Society guidelines 1 allow either method.

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Stress Dosing (Non-Crisis Situations)

Major Surgery/Trauma/Severe Illness

For procedures requiring general anesthesia, major trauma, delivery, or ICU-level care:

Adults:

• 100 mg IV hydrocortisone bolus at induction 1
• Followed by 200 mg/24 hours continuous infusion 1
• Continue until patient stable, typically 1-2 days 4

Children:

• 50 mg/m² IV bolus 1
• Followed by 50-100 mg/m²/day divided every 6 hours 1

Minor to Moderate Surgical Stress

For procedures under local anesthesia or minor surgery:

Adults:

• 25-75 mg/24 hours for 1-2 days 1

Children:

• 50 mg/m² IM or double/triple usual replacement doses 1

Unable to Tolerate Oral Medication

For gastroenteritis or vomiting without hemodynamic instability:

Adults:

• 100 mg IM or SC hydrocortisone 1
• Note: The 2013 study 5 validated SC administration as effective with only 11-minute delay to therapeutic levels versus IM

Children:

• 50 mg/m² IM (practical: infants 25 mg, school-age 50 mg, adolescents 100 mg) 1

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Routine Replacement (Moderate Stress)

For glucocorticoid-induced adrenal insufficiency during illness:

• Double the physiologic dose: 40 mg hydrocortisone daily in divided doses (20 mg morning, 10 mg midday, 10 mg evening) 4
• For fever: Double dose at 38°C, triple at 39°C until recovery 1
• Duration: Continue until stress resolves, typically 2-3 days 1

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Administration Routes & Practical Considerations

Route Preference Hierarchy

1. IV push (preferred for emergencies) 2
2. Continuous IV infusion (best for sustained stress) 3
3. IM injection (when IV access unavailable)
4. SC injection (acceptable alternative, patient-preferred) 5

Common Pitfalls to Avoid

Under-dosing is more dangerous than over-dosing in acute crisis—the guidelines emphasize this explicitly 1. When in doubt, give the full 100 mg bolus.

Hypernatremia risk: If high-dose therapy continues beyond 48-72 hours, consider switching to methylprednisolone which causes less sodium retention 2

Don't delay for diagnostic testing: Treat suspected adrenal crisis immediately; confirmation can wait 4, 1

Reconstitution: Use ≤2 mL diluent per vial; for infusion, can add to 100-1000 mL D5W or normal saline 2

Tapering: After crisis resolution, taper gradually rather than stopping abruptly 2

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Alternative Glucocorticoids

If hydrocortisone unavailable 1:

• Second choice: Prednisolone
• Last resort only: Dexamethasone (least preferred due to lack of mineralocorticoid activity)

The 2024 European/Endocrine Society joint guideline 4 and 2016 Endocrine Society guideline 1 provide the framework, with the FDA label 2 confirming dosing ranges of 100-500 mg initial dose, repeatable every 2-6 hours based on response.