Researchers attempted to quantify the effect that Florida's Prescription Drug Monitoring Program (PDMP) had on overall and high-risk opioid prescribing and use. Main outcomes included total opioid volume, mean morphine milligram equivalent (MME) per transaction, mean days' supply per transaction, and total number of opioid prescriptions dispensed. Researchers analyzed data from July 2010 through September 2012, finding that Florida's laws were associated with statistically significant declines in opioid volume and MME per transaction, without change in days' supply. The state's policies were associated with a 1.4% decrease in opioid prescriptions, a 2.5% decrease in opioid volume, and a 5.6% decrease in MME per transaction 12 months after implementation. Investigators concluded that Florida's PDMP was associated with modest decreases in opioid prescribing and use. The decreases were greatest among those prescribers and patients who had the highest opioid prescribing and use before implementation.