By Josh Bloom and Lynn Webster
Ten years after the publication of the 2016 CDC opioid guideline, enough time has passed to examine what followed. Consider this a biopsy of a decade of American pain policy — not an examination of what policymakers intended, but of what the tissue now shows.
What happened to opioid prescribing? What happened to overdose deaths? What happened to physicians? And, most importantly, what happened to people living in pain?
Although the war on pain patients arguably began in the early 2010s, its nadir was reached with the publication of the CDC Guideline for Prescribing Opioids for Chronic Pain in 2016.
While the war on drugs has been an unmitigated disaster, the accompanying war against people in pain was an unqualified "success." And much of it was built on bad science and pharmacology.
Bad science is bad enough. But bad science turned into policy is worse, because real people have to live with it. That is, if day after day of under- or untreated pain really can be called living.
MME: The Illusion of Precision
The CDC's reliance on Morphine Milligram Equivalents (MME) had one very attractive feature: simplicity. Assign every opioid a number based on its potency relative to morphine, do some menial arithmetic, and you've solved a very complicated pharmacological problem.
Except you haven't.
The idea sounds reasonable. Morphine is assigned a value of 1.0. Other opioids are given conversion factors relative to morphine. In the 2016 CDC table, oxycodone was assigned a value of 1.5 and oxymorphone 3. So, according to the table, 60 mg of oxycodone or 30 mg of oxymorphone was equivalent to 90 mg of morphine.
Simple. Convenient. The arithmetic works perfectly. But the pharmacology doesn't.
The problem is that neither the drugs nor the people who take them fit neatly into an Excel sheet.
Consider oxycodone and oxymorphone, both strong opioids. They are chemically related, yet the body handles them very differently. Oral oxycodone has a bioavailability of roughly 60–87%; for oxymorphone, it is only about 10%. Their metabolism differs as well: oxycodone undergoes extensive metabolism involving CYP enzymes, while oxymorphone undergoes extensive glucuronidation mediated by an entirely different family of enzymes.
These are not trivial pharmacological differences, but MME reduces them to a pair of numbers that look far more meaningful than they are.
Genes Make the Numbers Even Worse
And then there are genetics. Two people can take the same drug at the same dose and process it very differently, sometimes very differently.
Yet MME ignores all this, squeezing pharmacological variation into a single, geneless number.
Even the CDC acknowledged the problem. Its 2016 guideline cautioned that equianalgesic conversions are only estimates and cannot account for individual variability in genetics and pharmacokinetics. It also warned physicians not to use calculated MME values to determine doses when switching patients from one opioid to another because doing so could cause an overdose.
Someone wasn't paying attention.
The numbers aren't reliable enough to tell a physician precisely how much of Drug B should replace Drug A for an individual patient. Yet those same "approximate" conversions were considered reliable enough to determine whether that patient had crossed an official dosage threshold.
And then things got bad.
Enter the Thresholds
The CDC advised physicians to "carefully reassess" benefits and risks when increasing a patient's dose to 50 MME per day and to avoid—or carefully justify—doses of 90 MME or more. The guideline itself acknowledged that a single dosage threshold for safe opioid use could not be identified.
Nevertheless, 50 and especially 90 MME rapidly acquired significance far beyond what the underlying pharmacology could justify.
This is false precision.
MME can be useful as a rough measure of opioid exposure. It allows researchers to put different opioids into approximately comparable units. But an approximate population-level tool is a very different thing from a scientifically determined limit for an individual patient.
There is no pharmacological cliff at 50 MME. Nor does something suddenly happen to a patient when the dose reaches 90.
Yet numbers have a way of acquiring authority once they appear in an official government document. What began as a rough conversion method became embedded in prescribing policies, insurance rules, state laws, and medical practice.
And that's where a questionable pharmacological construct stopped being merely a scientific problem.
It became a human one; more accurately, an inhumane one.
Impact on Physicians and Patients
The 2016 guideline accelerated a fundamental change in how medicine viewed pain, people living with pain, and opioid therapy itself. Insurers, policymakers, and the medical community increasingly shifted their attention away from the undertreatment of pain and toward reducing opioid exposure. Although addiction and overdoses were stated public health concerns, reducing opioid prescribing became a principal policy response.
This shift was reinforced by a wave of opioid litigation that portrayed prescription opioids, and often the physicians who prescribed them, as central contributors to the overdose crisis. A relatively simple narrative became dominant: that prescription opioids were inherently highly addictive, broadly ineffective for chronic pain, and responsible for an extraordinary number of overdose deaths.
Important distinctions were often lost in the process: prescription opioids versus illicit opioids, therapeutic use versus misuse, physical dependence versus addiction, association versus causation, and population-level risk versus the needs of an individual patient.
The result was not simply a change in prescribing recommendations. It was a change in the culture of medicine.
For physicians, the incentives became increasingly clear. Prescribing fewer opioids was viewed as safer and more defensible. Continuing opioid therapy could bring scrutiny from medical boards or law enforcement. Physicians reduced doses, tapered established patients, became reluctant to accept patients already receiving long-term opioid therapy, and in some cases stopped treating pain altogether.
The message was unmistakable: opioids were a risk not only to patients but to physicians as well.
Federal enforcement amplified that message. The DEA and Department of Justice made highly visible the consequences of being identified as an excessive opioid prescriber. Physicians watched colleagues be investigated and raided, lose DEA registrations, face prosecution, and sometimes receive lengthy prison sentences.
At the same time, federal and state agencies increasingly used data analytics, peer-prescribing comparisons, and warning letters to identify prescribing outliers.
But patients living with pain paid a substantial price.
As clinicians became more reluctant to prescribe, patients encountered increasing difficulty finding physicians willing to assume their care or continue treatments that had been stable for years. Some experienced involuntary dose reductions or discontinuation. Others struggled to maintain continuity of treatment or felt increasingly viewed with suspicion simply because their medical care included an opioid.
Remarkably, the 2022 CDC guideline acknowledged much of what had gone wrong. It noted that policies derived from the 2016 guideline had sometimes gone "well beyond" its recommendations, including rigid dosage thresholds, rapid tapers, abrupt discontinuation, insurance and pharmacy limits, and even patient abandonment. The CDC concluded that these misapplications had contributed to patient harm, including untreated or undertreated pain, withdrawal, psychological distress, overdose, and suicidal ideation.
There is also a paradox that any ten-year assessment must confront. Opioid prescribing declined substantially during this period, yet the overdose crisis did not end. Instead, mortality became increasingly dominated by illicitly manufactured fentanyl and other hazards of an unpredictable illicit drug supply.
This does not establish that reductions in prescribing caused subsequent overdose deaths. But it does raise a fundamental question about the strategy: did reducing prescription opioid exposure become confused with addressing the causes of the overdose crisis itself?
The most consequential legacy of the post-2016 era, therefore, is not simply the reduction in opioid prescribing. It is the transformation of pain treatment from an effort to relieve suffering and preserve function into one increasingly organized around physicians avoiding opioid-related risk.
The lesson of the last decade is not that opioids are harmless, that every prescription was appropriate, or that the country should return to the prescribing practices of the 1990s. It is that public-health policy can cause harm when uncertainty is converted into certainty, population averages are applied to individuals, and a complex epidemic is reduced to a single measurable target.
In trying to protect patients from opioids, medicine lost sight of an equally important obligation: protecting people in pain from unnecessary suffering.
Josh Bloom, PhD, is Director of Chemical and Pharmaceutical Sciences at the American Council on Science and Health (ACSH).
Lynn Webster, MD, is a pain and addiction medicine specialist, and Senior Fellow at the Center for U.S. Policy. He is the author of “Deconstructing Toxic Narratives: Data, Disparities, and a New Path Forward in the Opioid Crisis.”
This article originally appeared in the American Council on Science and Health and is republished with permission.
