# A Case Report of Delayed Opioid Toxidrome After Administration of Naloxone

## TL;DR

A patient experienced delayed opioid toxicity after naloxone, suggesting current monitoring guidelines may be insufficient.

## Contribution

Highlights a case of delayed opioid toxidrome post-naloxone, challenging standard monitoring practices.

## Key findings

- A patient developed severe respiratory depression hours after naloxone administration.
- Delayed toxidrome may be due to fentanyl analogues or metabolism variability.
- Current four-hour observation period may not be sufficient for all patients.

## Abstract

Opioid use is an epidemic that plagues the United States. Patients frequently present to the emergency department (ED) after opioid toxicity, which can lead to respiratory failure, apnea, and death. Although there is an effective antidote, naloxone, the current guidelines surrounding post-naloxone administration monitoring are loosely defined.

We present a case in which an individual was administered naloxone after an intentional opioid overdose and was monitored for four hours, as is standard in our institution. He remained in the ED for additional workup following this observation period and subsequently experienced signs of severe respiratory depression, requiring bag-valve-mask ventilation, naloxone, and admission. Had he been discharged, as is typical after a four-hour observation period, the consequences could have been fatal. We present multiple theories as to why his opioid toxidrome may have presented in a delayed manner, including ingestion of fentanyl analogues and variability in metabolization of both opioids and naloxone. We also explore alternative overdose antidote products approved by the US Food and Drug Administration, which may impact post overdose care.

This case suggests that the correct amount of time to monitor patients after naloxone administration may be longer than originally thought. Our aim in this article was to further the discussion regarding the most appropriate observation period in cases of opioid toxicity.