Does Opioid Use Deterrence Increase Heroin Deaths? Evidence from the Reformulation of OxyContin
We examine the role of OxyContin reformulation on the recent dramatic rise in heroin-related mortality. In August 2010, an abuse-deterrent version of OxyContin was introduced, representing a reduction in the supply of abusable opioids. Time series evidence suggests a strong relationship between the OxyContin reformulation and the rise in heroin mortality, implying substitution towards heroin. We study the relative change in heroin-related mortality in states with higher pre-2010 rates of OxyContin misuse relative to states with lower rates of OxyContin misuse using data from the Centers for Disease Control Vital Statistics database. This approach allows us to condition on both state and time fixed effects instead of relying solely on overall trends. We find that OxyContin misuse is a strong predictor of larger increases in both heroin substance abuse treatment admissions and heroin-related mortality. There is little evidence that these results can be explained by differential pre-existing trends across states as both the trends and levels of heroin-related mortality were similar before 2010 across states with different rates of OxyContin misuse. Moreover, we find that the rise in heroin can be attributed specifically to pre-2010 misuse of OxyContin and not misuse of pain relievers more generally. While other changes in opioid supply occurred at approximately the same time as the OxyContin reformulation, these other factors appear to have little power in explaining recent trends in heroin use and mortality. Our results also show that the reformulation led to substitution towards more powerful legal opioids, and we observe little evidence of differential reductions in opioid-related harms.