TUESDAY, March 3, 2020 (HealthDay News) -- Opioid use in Florida fell after a law that restricted opioid prescriptions for acute pain was introduced in 2018, researchers report.

Under the law, opioid prescriptions for acute pain are limited to a three-day supply (with certain exceptions), and physicians and pharmacists must use the state's prescription drug monitoring database to review a patient's prescription history.

The number of new opioid users per month dropped 16% immediately after the law was implemented in July 2018, and the number of new users continues to decline each month, according to the University of Florida study.

The study also found that patients' average supply of opioids fell from 5.4 days to three days, and that the law was associated with an immediate drop in the use of hydrocodone, the most commonly used Schedule II opioid.

"The Florida law is among the most restrictive in the country by limiting patients to a three-day opioid supply for acute pain," said study author Juan Hincapie-Castillo, an assistant professor of pharmaceutical outcomes and policy in the university's College of Pharmacy.

"We expected to find a decrease in opioid use following the law, but we did not anticipate the significant decline in the number of users," Hincapie-Castillo added in a university news release.

The findings were published online Feb. 28 in JAMA Network Open.

According to study co-author Amie Goodin, "In July 2018, people were walking away with six days' worth of medications. By the end of the study period eight months later, people were walking away with three days' medications -- half the amount of treatment for all the same conditions." Goodin is also an assistant professor of pharmaceutical outcomes and policy in the College of Pharmacy.

Still, the Florida law -- which only covers opioid prescriptions for acute pain, not chronic pain conditions such as cancer and trauma -- is not well-defined in terms of diagnosis and can cause confusion among prescribers, the study authors noted.

More than 30 states have opioid restriction laws, and many other states are considering similar laws.

More information

The U.S. National Institute on Drug Abuse has more about prescription opioids.