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Epinephrine absorption in adults: Intramuscular versus subcutaneous injection,☆☆

https://doi.org/10.1067/mai.2001.119409Get rights and content

Abstract

We report a prospective, randomized, blinded, placebo-controlled, 6-way crossover study of intramuscular versus subcutaneous injection of epinephrine in young men. Peak plasma epinephrine concentrations were significantly higher (P < .01) after epinephrine was injected intramuscularly into the thigh than after epinephrine was injected intramuscularly or subcutaneously into the upper arm. We recommend intramuscular injection of epinephrine into the thigh as the preferred route and site of injection of this life-saving medication in the initial treatment of anaphylaxis. (J Allergy Clin Immunol 2001;108:871-3.)

Section snippets

Methods

We tested this hypothesis in a prospective, randomized, blinded, placebo-controlled, 6-way crossover study in healthy allergic men age 18 to 35 years. The project was approved by the University of Manitoba Research Ethics Board, and each participant gave signed, informed consent before study entry.

Prospective subjects were excluded if they had any history of cardiovascular, thyroid, or central nervous system disorder or if they smoked or used any medications or recreational drugs. Participants

Results

Thirteen men (26 ± 2 years; weight, 85 ± 5 kg [range, 62-114 kg]; body mass index, 36.6 ± 4.6 [range, 20-64]) completed the study. Mean plasma epinephrine concentrations versus time are shown in Fig 1.

. Mean plasma epinephrine concentrations versus time are shown after administration of an identical 0.3-mg (0.3-mL) dose of epinephrine by IM or SC injection in 2 different sites. T, Thigh; A, upper arm. Mean endogenous plasma epinephrine concentrations are shown after IM or SC injection of 0.9%

Discussion

This study supports the superiority of IM injection of epinephrine into the thigh in adults, either as 0.3 mg (0.3 mL) from an ampule or as 0.3 mg (0.3 mL) from an EpiPen. In contrast, an identical dose of epinephrine injected IM into the deltoid or injected SC in the deltoid region did not result in significant elevation of plasma epinephrine concentrations in comparison with endogenous epinephrine concentrations measured after saline solution injections. The greater absorption of epinephrine

Acknowledgements

We sincerely thank all of the participants in the study. We also acknowledge the excellent professional assistance of Lana M. Johnston, RN, and Cathy A. Gillespie, RN, BA.

References (10)

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Funding provided by the Children's Hospital Foundation of Manitoba, Inc. The authors received no financial or in-kind support from any corporate sponsor for this research project.

☆☆

Reprint requests: F. E. R. Simons, MD, FRCPC, Children's Hospital of Winnipeg, 820 Sherbrook Street, Winnipeg, Manitoba, Canada R3A 1R9.

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