“These findings indicate law enforcement efforts to shut down pill-mill prescribers are insufficient to address the widespread overprescribing of opioids,” Chen said. “Efforts to curtail national opioid overprescribing must address a broad swath of prescribers to be effective.”

He noted in a subsequent JAMA essay that, “While many clinical topics compete for education priority, prescription drug misuse and addiction is one that an inadequately trained medical community will routinely contribute to, if not overtly cause. Facing this is challenging, but I recall one of my medical school attending’s teachings: The patient you least want to see is probably the one who needs you the most.”

Though some research has suggested the opioid epidemic is being stoked by a small group of bad actors operating out of backroom pill mills, researchers with the Center for Primary Care and Outcomes Research (PCOR) have found that prescribing painkillers is widespread among general practitioners.

Despite public policy efforts, overdoses from prescribed narcotics such as morphine, oxycodone and hydrocodone have reached record highs. The Centers for Disease Control and Prevention reports opioid overdoses have quadrupled since 2000.

The PCOR study, which examined Medicare prescription drug claims data for 2013, appeared in a research letter published in JAMA Internal Medicine.

“The bulk of opioid prescriptions are distributed by the large population of general practitioners,” said lead author Jonathan Chen, MD, PhD, an instructor of medicine and former Stanford Health Policy VA Medical Informatics fellow.

The researchers found that the top 10 percent of opioid prescribers account for 57 percent of opioid prescriptions. This prescribing pattern is comparable to that found in the Medicare data for prescribers of all drugs: The top 10 percent of all drug prescribers account for 63 percent of all drug prescriptions.

The specialties of family practice and internal medicine prescribed the most Schedule II opioids approved by the Food and Drug Administration in 2013, followed by nurse practitioners and physician assistants, according to the study.

“These findings indicate law enforcement efforts to shut down pill-mill prescribers are insufficient to address the widespread overprescribing of opioids,” Chen said. “Efforts to curtail national opioid overprescribing must address a broad swath of prescribers to be effective.”

He noted in a subsequent JAMA essay that, “While many clinical topics compete for education priority, prescription drug misuse and addiction is one that an inadequately trained medical community will routinely contribute to, if not overtly cause. Facing this is challenging, but I recall one of my medical school attending’s teachings: The patient you least want to see is probably the one who needs you the most.”

A study by the California Workers’ Compensation Institute in 2011 found that one percent of prescribers accounted for one-third of opioid prescriptions, and that the top 10 percent accounted for 80 percent of prescriptions.

The newer PCOR study used a different data set. Instead of California Workers’ Compensation prescriptions, it looked at prescriber data from the 2013 Medicare prescription drug coverage claims and investigated whether such disproportionate prescribing of opioids occurs in the national Medicare population.

Both studies looked at Schedule II opioids, which include the commonly abused drugs hydrocodone, codeine and fentanyl, the drug responsible for the recent accidental overdose death of legendary musician Prince.

The data set created by the Centers for Medicare and Medicaid Services included all prescribers and represented all Medicare prescription drug coverage claims for 2013. The researchers focused on the data for Schedule II opioids: 381,575 prescribers and 56.5 million claims.

“The earlier study suggests potentially aberrant behavior among those extreme outlier prescribers, while implying the remaining majority do not contribute much to the problem,” said Chen. “And now we know this is not the case.”

Associate professor of medicine Nigam Shah, MBBS, PhD, was a co-author; assistant professor of psychiatry and behavioral sciences Anna Lembke, MD, was the study’s senior author; and professor of psychiatry and behavioral sciences Keith Humphreys, PhD, was a co-author.