“The policy was intended to reduce the quantity prescribed but it was not expected to decrease opioid use overall,” said study coauthor Dr. Juan Hincapie-Castillo of the University of Florida College of Pharmacy in Gainesville. “But fewer people were getting opioids. That means the law led not only to a reduction in the quantity dispensed, but also to a reduction in the initial decision to prescribe.”

At this point it’s not clear what medications doctors were choosing to prescribe in place of opioids, Hincapie-Castillo said. “We know that some patients are not getting opioids, so, are they getting more non-steroidal anti-inflammatory drugs, like ibuprofen or naproxen, or other medications, like gabapentin?” he said. “We don’t know yet.”

While it’s good to see a reduction in the amount of opioids prescribed overall, Hincapie-Castillo worries that laws like the one in Florida might also make doctors less likely to write prescriptions for patients with chronic pain, says a Reuters report.

Hincapie-Castillo and his colleagues analyzed pharmacy prescription claims for opioids dispensed from January 2015 through March 2019 in a single health plan covering more than 45,000 people, says the Reuters report. To focus on patients who were newly prescribed opioids and continuously using the medication, the researchers made sure none had a prescription for the drugs in the previous 180 days. Hincapie-Castillo and his colleagues identified 8,375 patients with 10,583 unique new opioid prescriptions. There were more prescriptions than patients because individual patients might have had a prescription for opioids more than once during the years covered by the study, Hincapie-Castillo explained.

Before the new legislation, 5.5 per 1,000 patients started a new prescription for opioids. That dropped to 4.6 per 1,000 after the law was implemented, says the Reuters report.

After the law was in effect, there was also an immediate decrease of 0.48 patients per 1,000 in monthly users of hydrocodone, which is often sold in combination formulas containing ibuprofen or other over the counter pain medicines. Other weaker opioids also saw a 0.24 per 1,000 drop in monthly users after the law. The average number of days included in opioid prescriptions also dropped from 5.4 to 4.2 and continued to decrease over the eight months following implementation of the law.

“The study shows that if you change the law, you will likely change prescriber behavior,” said Dr. Yury Khelemsky, an associate professor of anesthesiology, perioperative and pain medicine at the Icahn School of Medicine at Mount Sinai in New York City. “And that make sense because physicians tend to be pretty compliant with regulatory issues.”