In the fight against overprescribing opioids, prescription drug monitoring programs (PDMPs) have become an effective tool in many states. But it's not fully understood what makes these programs successful.  

In a paper in the American Economic Journal: Economic Policy, authors Abby Alpert, Sarah Dykstra, and Mireille Jacobson argue that although PDMPs were designed to decrease inappropriate opioid prescriptions by providing more information about relevant patient history, the primary reduction resulted from the hassle costs of the required record checks.

Their findings come from studying the state of Kentucky’s landmark PDMP law. Beginning in July 2012, the law mandated that pharmacists and physicians register with the PDMP and query a PMDP database before prescribing controlled substances containing hydrocodone.

The database allowed doctors to view a patient’s prescription history and identify patterns of misuse—such as “doctor shopping” or obtaining unusually large quantities or high dosages of opioids. Ideally, providers would use the information to prescribe opioids to patients without a pattern of problematic behaviors and limit prescriptions to patients with suspicious histories. 

In order to assess how the law was working, the authors compared the rates at which providers prescribed opioids to so-called “naïve” patients—those without problematic histories—to “nonnaïve” patients. Panel B of Figure 2 from the authors’ paper shows what happened to opioid prescriptions for both groups after Kentucky’s PDMP law went into effect.

Panel B of figure 2 from Alpert et al. (2024)

The x-axis indicates the quarters before and after Kentucky’s PDMP mandate was implemented (red vertical line). The y-axis indicates event study estimates of the rate of receiving an opioid prescription after an emergency department visit in Kentucky relative to states without PDMP mandates. The green series represents naïve patients, while the red series represents nonnaïve patients.

The chart shows that immediately after the Kentucky law went into effect, both types of patients were much less likely to be prescribed an opioid compared to similar patients in states without a mandate. Since nothing in the PDMP database should have led providers to reduce prescribing to the naïve group, this across-the-board drop in prescription rates suggests that doctors found checking the PDMP a burden. If they were using the PDMP database to effectively identify patients with a history of misusing opioids, there would have been no drop among the naïve group.

Overall, the researchers calculate that hassle costs from the mandate—rather than greater access to patient history information—explained nearly 70 percent of the decline in prescribing. However, they also argue that long-term patient outcomes may have improved on the whole, as the decline in prescriptions that were the result of access to better information was concentrated in patients with a history of opioid prescriptions.