The effects of North Carolina's prescription drug monitoring program on the prescribing behaviors of the state's providers.

State-level prescription drug monitoring programs (PDMPs) show promise as a key strategy to respond to the epidemic of the misuse and abuse of controlled substances (CS), particularly opioid analgesics, in the United States. Undocumented concerns have been expressed that these PDMPs may have a "chilling effect" on providers' willingness to prescribe these substances to their patients. Using data from North Carolina's PDMP for the 3-year period from 2009 through 2011, we examined whether rapid increases in (1) the number of providers who queried the system, and (2) the number of days on which they queried it, would be related to their prescribing practices in regards to CS. We hypothesized that neither marker of PDMP utilization would be associated with a decrease in either patients receiving CS prescriptions or CS prescriptions filled. We found no association between either of these variables and the number of patients who filled prescriptions for CS or the number of prescriptions for CS filled. However, we did find a slight positive relationship between the growth in the utilization of the PDMP and the number of prescriptions filled for opioid analgesics. Concerns that PDMPs may constrain prescribing behavior with regards to CS are not supported.