Arizona's Naloxone Coprescription Law: Impact on Naloxone Prescriptions for Patients Receiving High-Dose Opioids

Recognizing naloxone's role in reversing opioid overdoses, Arizona enacted a law requiring naloxone coprescription with high-dose opioids. This study evaluates the law's impact on naloxone coprescribing for these opioids. Secondary analyses examine potential spillover effects on naloxone coprescribing for lower-dose opioids and on naloxone dispensed under standing orders, which allowed pharmacists to provide naloxone without a patient-specific prescription.

Arizona's law, implemented in April 2018, was evaluated using interrupted time series analyses with autoregressive integrated moving average models and Arizona Controlled Substances Prescription Monitoring Program data (2017-2022). The outcome was the monthly proportion of opioid prescriptions matched to naloxone prescriptions or naloxone dispensed under standing orders. Proportions were stratified by opioid dose: high dose (≥120 and 90-119 morphine milligram equivalents), moderate dose (50-89 morphine milligram equivalents), and low dose (<50 morphine milligram equivalents). Analyses were completed in 2026.

For high-dose opioids, the law was associated with an initial 2-month spike in naloxone coprescribing-360% for ≥120 morphine milligram equivalents and 331% for 90-119 morphine milligram equivalents-and level increases of 123% and 97%, respectively. Although not targeted by the law, naloxone coprescribing for moderate-dose opioids also increased (a 215% spike and a 72% level increase). No level change was observed for low-dose opioids. Naloxone dispensed under standing orders and matched to opioid prescriptions increased across all dose categories after the law's implementation.

Arizona's coprescription law was associated with substantial increases in naloxone coprescribing for high-dose opioids. Positive spillover effects were observed for naloxone coprescribing with moderate-dose opioids and for naloxone dispensed under standing orders, suggesting broader changes in naloxone prescribing and dispensing.