Abstract
Anaphylaxis is a life-threatening multisystem allergic reaction that is treated with prompt intramuscular epinephrine administration. Although epinephrine autoinjectors such as the EpiPen and EpiPen Jr are widely used, they are limited to single-use doses, posing a significant challenge in austere or wilderness environments where medical evacuation may be delayed and rebound anaphylaxis may occur. Although some techniques have been described to extract residual epinephrine from adult EpiPens, mainly by deconstruction with a knife, no studies have addressed the use, safety, or mechanical specifics of disassembling the pediatric EpiPen Jr for redosing. This article presents a detailed analysis of the internal mechanism, medication concentration, and redosing potential of the EpiPen Jr, confirming that it shares the same device structure as the standard EpiPen but contains a lower concentration of epinephrine (0.15 vs 0.3 mg/0.3 mL). Instructions for mechanical disassembly and secondary dose extraction are provided, with considerations for sterility and administration technique. The article also outlines the risks of under- or overdosing in pediatric populations, cost barriers to carrying multiple devices, and the potential for adverse effects when redosing is imprecise. Further research is needed to assess the safety, reliability, and dosing accuracy of this method. Training and wilderness-specific protocols are recommended to ensure safe implementation in high-risk, resource-limited environments.
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