Efficacy of low-dose nebulized epinephrine as treatment for croup: A randomized, placebo-controlled, double-blind trial.

Objective: Croup treatment usually involves a single dose of systemic dexamethasone combined with nebulized epinephrine. However, the optimal dose of l-epinephrine remains unclear. We examined whether a low dose (0.1 mg/kg) was inferior to the conventional dose (0.5 mg/kg) of 1:1000 nebulized l-epinephrine in patients with moderate to severe croup.

Methods: This randomized double-blind clinical non-inferiority trial was conducted in three pediatric emergency departments from May 2015 to October 2017. Children 6 months to 5 years old with moderate to severe croup (Westley scale scores 3-11) were eligible. Subjects were randomly assigned to the conventional dose (0.5 mg/kg: maximum 5 mg) or low dose (0.1 mg/kg; maximum 1 mg) group. All subjects received 0.6 mg/kg dexamethasone. Croup scores and other vital signs were measured before and at 30, 60, 90, and 120 min after nebulized l-epinephrine administration. The primary outcome was the change in croup score after 30 min.

Results: The final analysis included 84 patients. The groups did not differ significantly in terms of demographic parameters. At 30 min after treatment with nebulized l-epinephrine, the croup scores in both groups were significantly reduced from the baseline values (p < 0.05) and did not differ between the two groups (p = 0.42). Neither blood pressure nor heart rate differed between the two groups.

Conclusions: Low-dose 1:1000 l-epinephrine was not inferior in croup score reduction to the conventional dose in patients with moderate to severe croup. Clinical trial No: NCT01664507, KCT0002318.