Naloxone-Induced Withdrawal in Individuals With and Without Fentanyl-Positive Urine Samples.

These data suggest that a standard naloxone dose can be equally effective at precipitating withdrawal in individuals using heroin with fentanyl compared to heroin without fentanyl. These data contribute to our understanding of how naloxone antagonizes the effects of fentanyl and may have significant implications for the clinical laboratory and opioid overdose. A prospective clinical laboratory study with the proper opioid maintenance controls is needed to provide a more definitive finding. (Am J Addict 2019;00:00-00).