How to prepare racemic epinephrine from epinephrine (Epi) 1:1000 for nebulization in croup treatment?

Preparing Epinephrine 1:1000 for Nebulization in Croup

When racemic epinephrine is unavailable, use L-epinephrine 1:1000 at a dose of 0.5 mL/kg (maximum 5 mL) diluted in normal saline for nebulization in croup. 1, 2

Standard Preparation Protocol

Using L-Epinephrine (1:1000) as Substitute for Racemic Epinephrine

• Calculate the dose: 0.5 mL/kg of epinephrine 1:1000 solution, with a maximum dose of 5 mL 1, 2
• Dilute in normal saline: Add the calculated dose to approximately 2-3 mL of normal saline in the nebulizer chamber 3, 4
• Administer via standard nebulizer: Use a standard jet nebulizer over 10-15 minutes until the medication is fully nebulized 3

Dosing Examples by Weight

• 10 kg child: 5 mL of epinephrine 1:1000 (already at maximum dose) 1
• 8 kg child: 4 mL of epinephrine 1:1000 1
• 6 kg child: 3 mL of epinephrine 1:1000 1

Critical Safety Considerations

Do Not Confuse Formulations

• Racemic epinephrine 2.25% solution is NOT the same as epinephrine 1:1000 - these are entirely different concentrations requiring different dosing 2
• If using actual racemic epinephrine 2.25%, the dose is only 0.05 mL/kg (maximum 0.5 mL) diluted in 2 mL normal saline 1, 2
• Many institutions use a standardized 0.5 mL dose of racemic epinephrine 2.25% for all patients regardless of weight 1, 2

Post-Administration Monitoring Requirements

• Observe for 2-3 hours after each dose to monitor for symptom rebound, as the effect is short-lived (1-2 hours) 3, 1, 5
• Do not discharge patients immediately after nebulized epinephrine administration due to risk of rebound symptoms 3, 5
• Traditional practice recommended admission after 2 doses, but recent evidence supports considering admission only after 3 total doses of epinephrine 3, 1, 5

Clinical Context and Efficacy

Expected Therapeutic Response

• Significant symptom improvement occurs at 30 minutes post-treatment with reduction in croup scores 6, 7
• The therapeutic effect is temporary and typically lasts only 1-2 hours 3, 1
• No significant difference exists between racemic epinephrine and L-epinephrine in clinical efficacy 7

Evidence Supporting L-Epinephrine Substitution

• L-epinephrine (1:1000) at 0.5 mL/kg is an acceptable substitute when racemic epinephrine is unavailable 1, 2
• Studies demonstrate equivalent efficacy between racemic and L-epinephrine formulations 7
• Lower doses (0.1 mg/kg) have been studied and found non-inferior to conventional doses (0.5 mg/kg) in moderate to severe croup 8

Common Pitfalls to Avoid

• Never use epinephrine for outpatient or home treatment due to short duration of action and potential for rebound 3, 1
• Do not use 1:10,000 epinephrine concentration - this is for cardiac arrest, not nebulization 2
• Avoid premature discharge before completing the 2-3 hour observation period 5
• Always administer corticosteroids concurrently - oral dexamethasone 0.6 mg/kg should be given to all croup patients regardless of severity 5, 4