Are Prescription Opioids Really the Same As Heroin?

By Roger Chriss, PNN Columnist

The new HBO documentary “The Crime of the Century” is garnering a lot of attention for its take on the opioid crisis. In the documentary, Dr. Andrew Kolodny, the founder of Physicians for Responsible Opioid Prescribing (PROP), claims that prescription opioids are “essentially heroin pills.”

This is a common claim. Dr. Corey Waller, an addiction and emergency medicine expert, recently testified in a West Virginia lawsuit that opioid drugs and heroin are "identical."

"The brain doesn't know the drug you just gave it," Waller said. "It just knows the action that it has."

But it’s not quite that simple. There are two standard ways to look at drugs: pharmacology and epidemiology. The former takes into account a drug’s chemical structure and mechanism of action in the human body. The latter looks at the public health effects of a drug.

Opioid Pharmacology

The National Institute on Drug Abuse (NIDA) explains that heroin is a type of opioid made from poppy plants that is “chemically similar and can produce similar effects” as prescription pain relievers.

But chemically similar does not mean functionally identical. Small chemical differences affect how quickly a drug is absorbed, how strongly it acts and how long it remains in the body. The specific action of each opioid drug at the various mu, kappa, and delta opioid receptors also varies, creating differing levels of analgesia and other effects.

For example, oxycodone’s chemical composition makes it a particularly powerful opioid.

“What's unique about oxycodone relative to other opioids is the speed at which it's presented to the brain,” anesthesiologist Dr. Heath McAnally explained in a recent MedPage Today op-ed. “And in that regard, oxycodone reigns supreme (rivaling heroin), likely having to do with the fact that oxycodone's transport across the blood-brain barrier is considerably faster and more efficient than that of other opioids.”

Further, oxycodone is more active at kappa opioid receptors, possibly explaining the harder withdrawal that some people experience. It also acts more strongly on mu receptors, which may explain its greater euphoria. Morphine, by contrast, is more prone to histamine effects like itching and is associated with less positive feelings.

The opioid tramadol is also a serotonin-norepinephrine reuptake inhibitor, while tapentadol is a norepinephrine reuptake inhibitor. Some people do not tolerate tramadol well, and there is less abuse of tapentadol than other prescription opioids. They are very different than heroin.

Opioid Epidemiology

A 2013 study found that about 80% of heroin users first misused prescription opioids, but in more recent years heroin has become the first opioid people abuse in many cases. Heroin’s so-called “capture rate” -- a proxy for the addictiveness of a substance -- is thought to be about 25 percent.

By contrast, NIDA says about 8-12% of people on long-term prescription opioids develop some form of opioid use disorder, and less than 4% of people who misuse prescription pain medication start using heroin within five years.

Among prescription opioids, oxycodone is the most abused. According to a 2020 DEA report, the diversion and abuse of oxycodone “has become a major public health problem in recent years.”

Street prices and illicit sales are similarly revealing. Prescription opioids sold illegally are not all priced the same, nor treated with the same level of interest. There is a clear hierarchy, with oxycodone on top.

But the key driver in the overdose crisis today is illicit fentanyl made in clandestine labs and sold illegally on the street or online, often adulterating heroin or used in counterfeit oxycodone or Xanax pills.

Illicit fentanyl’s impact on the U.S. overdose crisis cannot be overstated. Other opioids, including heroin, do not come close to its level of abuse, addiction and death. Meanwhile, countries like Germany have not seen an opioid crisis, even though Germans are the second largest consumers of opioids worldwide.

It is also important to note that prescription opioids are medically essential, not only for pain management but also when sedating Covid-19 patients for ventilator use, for controlling air hunger in congestive heart failure, and for hospice and palliative care. Prescription opioids are medically useful in ways that heroin is not.

The claim that prescription opioids are identical to heroin does not hold up well. It obscures important information about opioid pharmacology and epidemiology. It may make a good soundbite, but it doesn’t shed light on the risks of opioids or how to address the overdose crisis.

Roger Chriss lives with Ehlers Danlos syndrome and is a proud member of the Ehlers-Danlos Society. Roger is a technical consultant in Washington state, where he specializes in mathematics and research.