The effectiveness of naloxone in reversing opioid overdose: The European naloxone outcome research study (NalPORS)
Background: Worldwide, opioid use causes more than 100,000 overdose (OD) deaths annually. Take-Home Naloxone(THN) programs have been introduced in many European countries targeting at-risk populations. Naloxone has proven efficacy in reversing opioid ODs when administered timely and at the right dose. THN programmes have been introduced to provide community members who are likely to witness an opioid OD with a naloxone kit and train them on how to recognise an OD and administer naloxone. The real-life effectiveness of naloxone administration by community members is unknown. In recent years, the approval of several concentrated naloxone nasal-spray formulations in addition to injectable formulations potentially increases acceptability and scope for wider provision. This study aims to determine the effectiveness of THN (all formulations) in real-world conditions when administered by community members to reverse opioid OD.
Methods: A European, observational cohort study was conducted. Participants supplied with THN were recruited from treatment and harm reduction services in England, Wales, Scotland and Sweden between June 2021 and March 2024 and followed-up for 6 months. They included: people who use opioids and were in treatment/out of treatment; friends, family members or carers, and staff working with people who use opioids. Participants witnessing an OD during the six-month period were asked to complete a structured questionnaire about the event, administered by a researcher. One witnessed OD event was captured per participant. Questions included: characteristics of the person experiencing the OD, location of OD, availability, and administration of naloxone (including type and dose), wider responses to the OD apart from naloxone, type and frequency of any reactions to naloxone, and outcome (recovery/fatality).
Results: THN was supplied to all NalPORS participants (n=1296 as of November 2023) (60% (771) injectable; 35% (453) nasal; and 5% (66) both, (6 missing)), of whom, 243 (19%) reported witnessing an OD and completed a structured questionnaire about the event. Among the 243 witnessed ODs, naloxone was administered at 82% (200/243) of OD events. Injectable naloxone was administered in 54% (108/200) of ODs and nasal naloxone in 46% (91/200) of ODs(1 missing), where naloxone was administered. In 89% of ODs, the individual was reported to have recovered. These are provisional data which will be updated before the conference. Opioids and other drugs contributing to the OD will be reported together with naloxone dose administered, wider responses to the OD, type and frequency of any reactions to naloxone, and survival rates. Findings will be presented by country and type of recruitment site.
Conclusion: Naloxone was successfully administered in the large majority of witnessed OD events. We will discuss how our findings increase understanding of the witnessed OD event and the administration of naloxone by community members in a real-world setting.
