Prescription opioid spillovers: Retail pharmacy level analysis

Prescription drug monitoring programs (PDMPs) are state-level initiatives designed to curb opioid misuse. This study investigates the impact of "must-access" PDMP mandates-which require healthcare providers to consult the PDMP database before prescribing opioids-on retail opioid sales in the United States. It also examines potential spillover effects on neighboring states without such mandates.

A generalized difference-in-differences analysis assessed the effect of PDMP mandate implementation on retail opioid sales from 2006 to 2014. The study utilized geocoded data encompassing the universe of individual retail pharmacies across the United States. This methodology allowed for the comparison of opioid sales trends in states implementing "must-access" PDMP policies with those that did not, both before and after policy enactment. The geocoded pharmacy data facilitated the analysis of spatial spillover effects on neighboring states.

This study provides evidence that the implementation of "must-access" PDMP mandates was associated with a decrease in retail opioid sales within the enacting states. Furthermore, results suggest the presence of spillover effects in pharmacies in neighboring states without such policies. This suggests that PDMP mandates in one state can influence opioid dispensing patterns in adjacent states.

State-level "must-access" PDMP mandates effectively reduce retail opioid sales within enacting states. However, observed spillover effects highlight the potential for state-level variation in opioid policy to generate unintended consequences. These findings highlight the potential for cross-state coordination in opioid policy to improve outcomes.