Revisiting the OxyContin reformulation: The role of licit substitutes

The proliferation of the high-dose prescription opioid product OxyContin has been identified as a major contributing factor to rising rates of opioid-involved harm throughout the early stages of the US opioid epidemic. Furthermore, after OxyContin was reformulated with abuse-deterrent properties in 2010, many people previously engaging in extramedical OxyContin use substituted to illicit substitutes, initiating a wave of heroin- and later synthetic opioid-involved deaths. Using event studies similar to those employed in previous OxyContin-related studies, we provide evidence that the OxyContin reformulation also induced substitution to another high-dose extended release (ER) prescription opioid product marketed under the brand name Opana ER. We show that the steady continued growth in prescription opioid-involved mortality after the OxyContin reformulation is nearly entirely explained by substitution from OxyContin to Opana ER. Furthermore, we show that when Opana ER itself was reformulated in February 2012, there was another wave of substitution to heroin previously attributed solely to OxyContin. Our estimates imply that if the Opana ER pathway were shut down at the time of the OxyContin reformulation, heroin-involved mortality from 2009 to 2016 in the US would have been as much as 33% lower, synthetic opioid-involved mortality as much as 38% lower, and total opioid-involved mortality as much as 44% lower. This study provides new evidence of the harms posed by high-dose prescription opioid products throughout the US opioid epidemic, as well as the unintended consequences of supply disruptions in the presence of both licit and illicit substitutes.