Prescriptions for hydrocodone analgesics abruptly and markedly declined after the U.S. Drug Enforcement Administration reclassified them from schedule III to the more restrictive schedule II of the Controlled Substances Act, according to a research letter to the editor published online in JAMA Internal Medicine Jan. 25.

Hydrocodone, usually formulated in combination with nonopioid analgesics, is one of the most frequently abused opioids, accounting for nearly 100,000 abuse-related emergency department visits during one recent year. In October 2014, the DEA rescheduled these agents to subject them to more rigorous control, said Christopher M. Jones, Pharm.D., MPH, of the Department of Health and Human Services, Washington, and his associates.

To assess any effect this rescheduling had on prescribing patterns, the investigators analyzed information in the IMS Health National Prescription Audit , a database that captures nearly 80% of all prescriptions dispensed from U.S. pharmacies, focusing on the 3 years before and the 1 year after rescheduling. They also analyzed information in an American Medical Association database to assess prescribing of hydrocodone combination agents across medical specialties during the year after rescheduling.

Prescriptions for hydrocodone combination agents decreased by 22% after rescheduling, and those for hydrocodone combination tablets decreased by 16%. There were 26.3 million fewer prescriptions for hydrocodone combination products, and 1.1 billion fewer hydrocodone combination tablets in the year after rescheduling.

Most of this decline (74%) was attributable to a profound reduction in refills, which is “consistent with the prohibition on prescription refills for schedule II medications,” Dr. Jones and his associates said (JAMA Intern Med. 2016 Jan 25. doi: 10.1001/jamainternmed.2015.7799).

In contrast, prescriptions for nonhydrocodone combination opioid analgesics increased by 5%, and those for nonhydrocodone tablets by 1%, during the year after rescheduling.

The reductions in prescribing occurred across most medical specialties. Surgeons and primary care physicians accounted for the largest decreases in both hydrocodone-containing prescriptions (-38.4% and -22.9%, respectively) and tablets (-30.8% and -17.1%, respectively). Oncologists, emergency medicine specialists, and nurse practitioners and physician assistants also contributed heavily to the declines. Dentists and physical/rehabilitation/occupational medicine specialists accounted for smaller reductions.

In contrast, pain medicine specialists showed modest increases in prescriptions for hydrocodone combination products and tablets.

“Future research should examine whether these changes are sustained, have had an effect on access for patients, and are associated with the desired goals of reduced abuse, addiction, and overdose,” Dr. Jones and his associates noted.

This study was funded by the U.S. Food and Drug Administration. Dr. Jones and his associates reported having no relevant financial disclosures.