Safety, Efficacy, and Cost of 0.4-mg Versus 2-mg Intranasal Naloxone for Treatment of Prehospital Opioid Overdose.

Background: Intranasal naloxone is commonly used to treat prehospital opioid overdose. However, the optimal dose is unclear, and currently, no study exists comparing the clinical effect of intranasal naloxone at different doses.

Objective: The goal of this investigation was to compare the safety, efficacy, and cost of 0.4- versus 2-mg intranasal naloxone for treatment of prehospital opioid overdose.

Methods: A retrospective, cross-sectional study was performed of 218 consecutive adult patients receiving intranasal naloxone in 2 neighboring counties in Southeast Michigan: one that used a 0.4-mg protocol and one that used a 2-mg protocol. Primary outcomes were response to initial dose, requirement of additional dosing, and incidence of adverse effects. Unpooled, 2-tailed, 2-sample -tests and χ tests for homogeneity were performed with statistical significance defined as <0.05.

Results: There was no statistically significant difference between the 2 populations in age, mass, gender, proportion of exposures suspected as heroin, response to initial dose, required redosing, or total number of doses by any route. The overall rate of adverse effects was 2.1% under the lower-dose protocol and 29% under the higher-dose protocol ( < 0.001). The lower-dose protocol was 79% less costly.

Conclusion And Relevance: Treatment of prehospital opioid overdose using intranasal naloxone at an initial dose of 0.4 mg was equally effective during the prehospital period as treatment at an initial dose of 2 mg, was associated with a lower rate of adverse effects, and represented a 79% reduction in cost.