Naloxone to revert synthetic opioids overdose — evidence summary

Summary of the evidence

Likely to be beneficial

Naloxone is recommended in an evidence-based guidance (Neptune, 2018) to be used in case of suspected synthetic opioids, both in community and hospital settings.

Specificities with regard to fentanyls in comparison to heroin overdoses are the followings:

  • a more rapid administration of naloxone is warranted because of the rapid onset of fentanyls,
  • a more rapid escalation of additional doses for naloxone may be needed in comparison with heroin or other opioids,
  • overall, higher doses of naloxone may be needed for fentanyl patients in comparison with heroin patients,
  • Fentanyl patients may require a longer period of observation in hospital than heroin patients.


Note: this evidence summary is only valid for the outcomes, target groups, settings and substances/patterns of use described below.

Name of response option:
pharmacological treatment
Desired outcome(s):
reduce mortality
Harm reduction
Specific substance or pattern of use:
new psychoactive substances (NPS)
prescription medicines
Target group(s) or setting(s):
emergency department
PWID – people who inject drugs