Does racemic epinephrine (epi) need to be mixed with normal saline for nebulization?

Racemic Epinephrine Nebulization: Saline Dilution Requirements

Yes, racemic epinephrine should be mixed with normal saline for nebulization. The standard pediatric guideline recommendation is 0.05 mL/kg (maximum 0.5 mL) of 2.25% racemic epinephrine diluted in 2 mL of normal saline for nebulization 1.

Standard Dilution Protocol

For racemic epinephrine (2.25% solution):

• Dilute 0.05 mL/kg (maximum 0.5 mL) in 2 mL of normal saline 1
• Many institutions use a standardized 0.5 mL dose of racemic epinephrine for all patients, regardless of weight 1
• This dilution is specifically recommended for treating laryngotracheobronchitis (croup) and acute airway edema 1

For L-epinephrine (1:1000 solution) as substitute:

• If racemic epinephrine is unavailable, use 0.5 mL/kg of 1:1000 L-epinephrine (maximum 5 mL) 1
• This also requires dilution for nebulization, though the specific saline volume is not explicitly stated in guidelines 1

Clinical Evidence Supporting Saline Dilution

Multiple research studies confirm the practice of diluting racemic epinephrine with normal saline:

• Adult upper airway obstruction cases were successfully treated with 1 mg racemic epinephrine in 5 mL of normal saline, repeated as necessary 2
• Pediatric bronchiolitis studies used 0.2 mL of racemic epinephrine added to 1.8 mL of distilled water (total 2 mL volume) 3
• Historical croup studies delivered racemic epinephrine via nebulizer with saline as the vehicle 4, 5

Why Saline Dilution Is Necessary

Practical considerations:

• The concentrated racemic epinephrine solution (2.25%) requires dilution to achieve adequate nebulization volume and particle size for effective delivery to the airways 1
• Saline serves as the vehicle for aerosolization, allowing the medication to be properly nebulized and inhaled 2
• Without adequate dilution, the small volume of concentrated drug would not nebulize effectively

Common Pitfalls to Avoid

Do not confuse with other epinephrine formulations:

• The FDA-approved epinephrine inhalation solution (1% concentration) for hand-held rubber bulb nebulizers does NOT require additional dilution, as it is already formulated for direct nebulization 6
• However, this is a different product than racemic epinephrine used in hospital settings 6

Dosing errors:

• Always verify you are using the 2.25% racemic epinephrine concentration when following the guideline dosing of 0.05 mL/kg in 2 mL saline 1
• Do not exceed the maximum 0.5 mL dose of racemic epinephrine per treatment 1