Stemming the Tide of the Xylazine Epidemic | Forensic Medicine at PCOM
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Stemming the Tide of the Xylazine Epidemic


March 11, 2024

It was not something that happened overnight. Over the span of several years, Montgomery County Chief Deputy Coroner Dr. Gregory McDonald noticed a disturbing trend—the incidence of xylazine-involved deaths were steadily increasing.

Dr. Gregory McDonald standing in front of a wall.
Dr. Gregory McDonald

“Forensics is a relatively small community,” McDonald said. “We started seeing an increase in this adulterant (xylazine). We’ve seen other adulterants that came from the veterinary side of medicine but not this one and it has gradually increased to the point that the majority of fentanyl-related deaths in our jurisdiction involve xylazine.”

National Institute of Health data shows xylazine-involved overdose deaths in Pennsylvania, where McDonald is based, increased from 259 per 100,000 residents in 2019 to 760 per 100,000 residents in 2022.

McDonald, who also serves as dean of PCOM’s School of Health Sciences and director of the MS in Forensic Medicine program, said this increase is consistent with what he has experienced.

“I work weekends typically and almost every weekend, I sign out one or two cases with xylazine as an adulterant as a contributing factor to the death,” he said.

Why is xylazine so deadly?

Xylazine, also known as tranq, is often mixed with another already dangerous drug—fentanyl.

“Fentanyl is an opiate—a very powerful opiate—that is being made in other countries and transported to the United States,” McDonald said.

Adding xylazine to a batch of fentanyl increases the bulk of the product available to sell—the greater the bulk, the greater the profit.

“It is a veterinary anesthesia—not approved for human use,” McDonald explained. “Veterinary drugs are a softer target. They are not as regulated and it is perhaps easier to get them than to rob a CVS.”

Like other opiates, xylazine acts as an anesthetic but it has a different mechanism of action.

“It has similar effects,” McDonald said. “It decreases blood pressure, slows heart rates producing bradycardia, and causes respiratory depression and drowsiness.”

This can lead to the zombie-like behaviors of tranq users depicted in videos recorded in the Kensington neighborhood of Philadelphia. While those videos have dominated media coverage, the same effects can occur with any opiate according to McDonald.

“Fentanyl, heroin and other opiates can do that, but when you combine it with xylazine, it has an additive effect,” he said. “The behaviors we unfortunately see in these vulnerable populations are usually a combination of these different illicit substances.”

The lack of quality control in the manufacturing of illicit drugs creates a dangerous situation in which the concentration of xylazine may vary from supplier to supplier, McDonald added. Users may find the effect they get from drugs acquired from one supplier may differ from another and, as a result, may tend to gravitate back to a particular supplier or location in an effort to replicate the high.

“It’s hard to predict the effects of these illicit drugs, that’s why they are so deadly,” he said.

Additionally, unlike other opiates, the effects of xylazine are harder to counteract.

“Things like NARCAN® (naloxone) can reverse the effects of opiates like fentanyl but it will not have an effect on xylazine,” McDonald explained. “Some medications in the veterinary field can reverse the effects of xylazine but they are not approved for human use.”

As a result, a xylazine overdose is not easily treated and can be fatal. When a drug fatality occurs, it is up to professionals like McDonald to determine if xylazine was a factor in the death.

Xylazine sores and other autopsy clues

Xylazine sores and skin ulcers are one clue that an individual may have died as a result of using a xylazine-laced drug.

As a vasoconstrictor, xylazine closes blood vessels.

Key Points
  • Xylazine, also known as tranq, is often mixed with fentanyl for increased profit.
  • This dangerous drug induces effects such as decreased blood pressure, slowed heart rates, and respiratory depression, leading to zombie-like behaviors.
  • The lack of quality control in illicit drug manufacturing results in unpredictable xylazine concentrations, ultimately contributing to fatalities.
  • Coroners and medical examiners provide critical data regarding drug involvement in fatalities, facilitating public health responses.

“The skin cannot get adequate blood supply and becomes necrotic causing ulcers to form at the injection site and sites distant from the injection site,” McDonald explained. “Ulcers get worse and worse and drug users might not seek medical treatment which can lead to amputation or sepsis.”

The majority of cases, however, do not involve xylazine wounds.

“Maybe 10% of the decedents I have examined had ulcers,” he said. “The drug is very unpredictable, so it is hard to say why some get skin ulcers.”

When doing an autopsy in a suspected drug overdose, McDonald looks for indicators including needle puncture sites and pulmonary edema in addition to xylazine sores. Toxicology tests, however, are key in determining which drug was involved in a fatality.

And while some causes of death may be more common for individuals of a certain age, xylazine-involved deaths have been observed across all ages.

“It is not just a disease of the young,” McDonald said.

Responding to the xylazine public health threat

McDonald and other coroners and medical examiners play an important role in providing critical information to the public health system. By identifying the specific drugs involved in overdose fatalities and noting them on the death certificate, that information can be distributed to agencies involved in monitoring and addressing public health threats.

“Having access to data about opiate deaths led to more access to NARCAN®,” McDonald explained. “Unfortunately that is not going to work for xylazine. Knowing the numbers—where the cases are, the demographics—can allow public health departments to monitor the situation, counsel people, provide rehabilitation programs and get more tax dollars.”

While McDonald admits treating xylazine users is challenging due to the highly addictive nature of the drug and the resulting recidivism rate, he emphasizes the xylazine epidemic is a problem that must be addressed.

“It crosses all age groups, all demographics—no one is immune to it,” he said. “It is everyone’s problem. It’s all of our problem. I wish I had better answers to it. I can just provide data to the people who hopefully stem the tide of this epidemic.”

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