What is nebulized racemic epinephrine?

Nebulized Racemic Epinephrine: Clinical Applications and Administration

Nebulized racemic epinephrine is a medication consisting of equal parts of the D-isomer and L-isomer of epinephrine, delivered via nebulizer, primarily used for temporary relief of airway edema through vasoconstriction in conditions like croup and, less commonly, in severe asthma exacerbations unresponsive to first-line therapies. 1

Composition and Formulation

• Racemic epinephrine contains equal parts of D-isomer and L-isomer of epinephrine, with the active ingredient being 11.25 mg of racepinephrine (as 13.5 mg of racepinephrine HCl) per 0.5 ml 2
• It is typically administered as an aqueous solution at a concentration equivalent to 1-2.25% epinephrine via nebulizer 2, 1

Primary Clinical Applications

Croup Treatment

• Standard dosing for croup is 0.05 mL/kg of 2.25% solution (maximum: 0.5 mL) in 2 mL of normal saline administered by nebulizer 1
• Many institutions use a standardized 0.5 mL dose for all patients regardless of weight 1
• If racemic epinephrine is unavailable, L-epinephrine (1:1000) can be substituted at a dose of 0.5 mL/kg up to 5 mL 1
• Provides clinically significant transient reduction of croup symptoms for approximately 30 minutes post-treatment through vasoconstriction and decreased mucosal edema 3
• No significant difference in efficacy between racemic epinephrine and L-epinephrine for croup treatment 3

Severe Asthma Exacerbations

• Not first-line therapy for asthma but may be considered in severe or life-threatening cases unresponsive to standard treatments 4, 5
• May be useful when patients are unable to cooperate with inhaled selective β2-agonist therapy 4
• For adults and children 4 years and older: 1 to 3 inhalations not more often than every 3 hours, with no more than 12 inhalations in 24 hours 2

Clinical Management Considerations

• Patients who receive racemic epinephrine for croup should be observed for 2-3 hours after administration to monitor for symptom rebound 1
• Traditionally, patients requiring 2 or more doses of racemic epinephrine in the ED were admitted for observation, but recent evidence suggests that up to 3 doses may be appropriate before admission 1, 6
• Children treated with racemic epinephrine, oral dexamethasone, and mist for croup may be safely discharged home if assessed as ready after 3 hours of observation 6

Efficacy Compared to Standard Treatments

• For croup: Nebulized epinephrine is associated with significant improvement in symptoms at 30 minutes post-treatment compared to placebo, but this effect is not significant at 2 and 6 hours 3
• For asthma: Current evidence suggests similar overall efficacy between epinephrine and selective β2-agonists in acute asthma 4, 7
• In children with asthma, nebulized racemic epinephrine has shown similar bronchodilatory effects to nebulized salbutamol in terms of increase in forced expiratory volume and duration of effect 7

Safety Considerations and Adverse Effects

• Adverse effects include increased heart rate, myocardial irritability, increased oxygen demand, and temporary sore throat 1, 7
• Should not be used in the home setting due to its short duration of action and potential adverse effects 1
• The use of this product by children should be supervised by an adult 2
• Small but significant increase in systolic blood pressure may occur after inhalation 7

Important Clinical Pearls

• Simple nebulization is as effective as delivery via intermittent positive pressure breathing (IPPB) 3, 8
• Racemic epinephrine should not be used in patients who are shortly to be discharged or on an outpatient basis without proper observation period 9, 1
• The American Academy of Pediatrics does not support routine use of racemic epinephrine for bronchiolitis among inpatients 1