The effect of cancer exemption in mandatory-access prescription drug monitoring programs among oncologists.

To address the opioid epidemic, some states mandate that prescribers review a state-run prescription drug monitoring program (PDMP) database before prescribing opioids. We used Medicare Part D prescriber data from 2013 (baseline) to 2019 to examine the association between state mandatory-access PDMPs, with and without a cancer exemption, and changes in the percent of oncologists' patients with any opioid fill per year, stratified by oncologists' baseline prescribing volume. Among 9746 medical or hematologic oncologists, the proportion of patients prescribed opioids declined after states implemented mandatory-access PDMPs without a cancer exemption overall (-0.49 percentage point, 95% confidence interval = -0.78 to -0.20 percentage point) and among those with above-median baseline prescribing, but not in states with a cancer exemption (-0.16 percentage point, 95% confidence interval = -0.50 to 0.18 percentage point) or with below-median baseline prescribing. Carefully designed mandatory-access PDMPs with cancer exemptions minimize unnecessary reductions in prescription opioid treatments among oncology patients in need of pain management.