Must-access prescription drug monitoring programs and the opioid overdose epidemic: The unintended consequences.

Although supply-side drug policies that limit access to legal opioids have reduced prescription opioid abuse, growing evidence shows that these policies have had the unintended consequence of increasing use of illegal opioids, including heroin. I add to this literature by studying the consequences of must-access prescription drug monitoring programs (PDMPs), which legally require providers to access a state-level database with a patient's prescription history before prescribing controlled substances under certain circumstances. Using a difference-in-differences specification, I find strong evidence that must-access PDMPs have increased heroin death rates. My estimates indicate that two years after implementation, must-access PDMPs were associated with 0.9 more heroin deaths per 100,000 in a half-year period, relative to control states. My results suggest that even if must-access PDMPs reduce prescription opioid deaths, the decrease is offset by a large increase in illegal opioid deaths.