INTRODUCTION: Some fear that distribution of naloxone to persons at risk of experiencing an opioid overdose may reduce the perceived negative consequences of drug use, leading to riskier patterns of use. This study assessed whether participation in naloxone/overdose training altered drug use frequency, quantity or severity among heroin users in and out of treatment.METHODS: Clinical interviews were performed assessing patterns of heroin and other drug use prior to, and at multiple timepoints after overdose education and naloxone training. This study compared baseline drug use to that at 1 and 3months post training.RESULTS: Both current heroin users (n=61) and former users in agonist maintenance (n=69) typically showed decreases in heroin and polydrug use at both 1 and 3months after training. The Addiction Severity Index drug composite score also decreased at follow up.CONCLUSIONS: This analysis found no evidence of compensatory drug use following naloxone/overdose training among two groups of heroin users. These findings support the acceptance and expansion of naloxone distribution to at-risk populations and may assist in allaying concerns about the potential for unintended negative consequences on drug use.