BackgroundPrison inmates face a ten times increased risk of experiencing a fatal drug overdose during their first 2 weeks upon release than their non-incarcerated counterparts. Naloxone, the antidote to an opioid overdose, has been shown to be feasible and effective when administered by bystanders. Given the particular risk that newly released inmates face, it is vital to assess their knowledge about opioid overdoses, as well as the impact of brief overdose prevention training conducted inside prisons.MethodsPrison inmates nearing release (within 6 months) in Oslo, Norway, voluntarily underwent a brief naloxone training. Using a questionnaire, inmates were assessed immediately prior to and following a naloxone training. Descriptive statistics were performed for main outcome variables, and the Wilcoxon signed-rank test was used to compare the participants’ two questionnaire scores from pre-and post-training.ResultsParticipating inmates (n = 31) were found to have a high baseline knowledge of risk factors, symptoms, and care regarding opioid overdoses. Nonetheless, a brief naloxone training session prior to release significantly improved knowledge scores in all areas assessed (p < 0.001). The training appears to be most beneficial in improving knowledge regarding the naloxone, including its use, effect, administration, and aftercare procedures.ConclusionsGiven the high risk of overdosing that prison inmates face upon release, the need for prevention programs is critical. Naloxone training in the prison setting may be an effective means of improving opioid overdose response knowledge for this particularly vulnerable group. Naloxone training provided in the prison setting may improve the ability of inmates to recognize and manage opioid overdoses after their release; however, further studies on a larger scale are needed.