What is the use of racemic epinephrine (adrenaline)?

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From the Guidelines

Racemic epinephrine should be used with caution in patients with croup, as it can reduce hospital admissions by 57% (95% CI: 24 to 89) according to a recent study 1. The medication is typically administered via nebulizer at a dose of 0.05 mL/kg of 2.25% solution (maximum 0.5 mL) diluted in 3 mL of normal saline. Some key points to consider when using racemic epinephrine include:

  • The onset of action is rapid (within minutes) but short-lived (1-2 hours), which can lead to "rebound" symptoms as it wears off 1.
  • Patients should be observed for at least 2-3 hours after administration to monitor for symptom recurrence.
  • Racemic epinephrine works by stimulating both alpha and beta-adrenergic receptors, causing vasoconstriction in the airway mucosa (reducing edema) and bronchodilation.
  • Side effects may include tachycardia, hypertension, and tremors.
  • Unlike regular epinephrine (which contains only the L-isomer), racemic epinephrine contains both D and L isomers, though the L-isomer provides most of the therapeutic effect.
  • It should be used cautiously in patients with cardiac conditions, and continuous cardiac monitoring is recommended during administration in healthcare settings. The most recent and highest quality study 1 suggests that the use of racemic epinephrine can lead to a significant reduction in hospital admissions for croup, without increasing the risk of inpatient airway interventions or length of stay. Some other key findings from this study include:
  • A modest reduction in total charges of $150 per encounter on average.
  • No significant changes in balancing measures, including inpatient airway interventions or length of stay.
  • The study found that the implementation of a clinical guideline and orderset can reduce hospital admissions for croup, and that racemic epinephrine can be an effective treatment option for patients with this condition.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Racemic Epinephrine Overview

  • Racemic epinephrine is used in the treatment of croup, a common childhood illness characterized by barky cough, stridor, hoarseness, and respiratory distress 2, 3, 4, 5, 6.
  • The efficacy and safety of nebulized epinephrine in children with croup have been evaluated in several studies, with results showing a transient reduction of symptoms 30 minutes post-treatment 3, 4.

Administration and Dosage

  • Nebulized epinephrine can be administered via intermittent positive pressure breathing (IPPB) or simple nebulization, with no significant difference in croup score between the two methods 3, 4.
  • The need for additional therapy (>2 doses of racemic epinephrine) among pediatric patients with croup has been associated with recent use of steroids within 1 day prior to presentation 5.

Outcomes and Variations

  • The use of racemic epinephrine in the emergency department (ED) varies widely across hospitals, with rates ranging from 14% to 48% of visits 6.
  • Increased ED use of racemic epinephrine has been associated with increased odds of hospital admission for individual patients, but not ICU admission or ED revisit 6.
  • Factors associated with the need for additional therapy among pediatric patients with croup include recent use of steroids, with the majority of patients requiring inpatient racemic epinephrine doing so within 8-12 hours 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Nebulized epinephrine for croup in children.

The Cochrane database of systematic reviews, 2013

Research

Nebulized epinephrine for croup in children.

The Cochrane database of systematic reviews, 2011

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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