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PHILADELPHIA — The volunteers were handing out the staples of harm reduction: safe injection and smoking kits, condoms, and Narcan, the opioid overdose reversal medication. Down the line, they were distributing hats, socks, coats, and blankets to the people who use drugs who came to this outreach event on a recent Saturday, a bright, cold morning a few days before Thanksgiving.

Just before the final table, where two mothers who had lost children to overdoses were passing out sandwiches, was evidence of the latest evolution in the increasingly dangerous U.S. drug supply. A wound care station.


“You have any wounds you need looked at?” volunteers asked people as they came through the event, held in this city’s Kensington neighborhood.

“Do I ever,” replied one man.

The spike in wounds among people who use drugs in Philadelphia reflects the surge in the local supply of a compound called xylazine. A veterinary tranquilizer, xylazine, or “tranq,” exploded in recent years to the point that in 2021, it was found in more than 90% of heroin and fentanyl samples. With its ascendance has come a wave of wounds — sometimes called abscesses, lesions, or, in the words of one volunteer nurse here, something that looks like “it’s eating away your flesh from the inside out.” The city saw the number of emergency department visits for skin and soft tissue injuries quadruple between the beginning of 2019 and the end of 2021.

“The wounds, for lack of a better term, are gnarly,” Jen Shinefeld, a field epidemiologist at the city’s health department, told STAT earlier this year.


These are not the same type of wounds that sometimes occur from injecting drugs generally. For one, they are sprouting on skin far from where people inject; there are reports that even people who snort or smoke xylazine-contaminated opioids — what’s called tranq dope — are developing these wounds. While they’re not caused by an infection, the wounds can get infected if they’re not taken care of.

And it’s not just the wounds. Xylazine is complicating overdose responses and withdrawal for people trying to reduce their illicit drug use. A powerful sedative, it can also knock people out for hours, leaving them vulnerable on sidewalks or even in the middle of the street.

The fear is that what’s happening with xylazine in Philadelphia — and what drug users, harm reduction groups, and medical providers are having to contend with — could be a preview of what’s headed to more places. Already, researchers have found burgeoning prevalences up and down the East Coast, and it’s starting to crop up in Chicago, Texas, and elsewhere. A study earlier this year raised the possibility of xylazine spidering out from the Northeast into markets westward, similar to the pattern illicit fentanyl took as it embedded itself in the drug supply. Researchers caution they can’t predict xylazine’s path or what prevalence it will reach, but warn that a lack of testing for xylazine is limiting detection.

Just last month, the Food and Drug Administration warned about the impact of xylazine as it infiltrates supplies of heroin and fentanyl.

“I’ve been jumping up and down like a maniac for three years trying to get attention on this,” said Sarah Laurel LaCerra, the executive director of Savage Sisters, the harm reduction group that organized the outreach event at McPherson Square Park (sometimes dismissed as “Needle Park”). Even as Savage Sisters has increased how often it’s offering wound care in the community, and Laurel LaCerra has tried to spread the word to politicians and public health leaders and on TikTok, “what we’re doing is a Band-Aid on a bullet hole,” she said.

Or, as one recipient said as he took a sandwich-bag packed with alcohol pads, gauze, and antibiotic ointment from the wound care table, “It’s crazy this stuff, it’s burning through our bodies.”

Savage Sisters distribute informational cards about xylazine to people who use drugs.
Savage Sisters distributes informational cards about xylazine to people who use drugs.

As experts rush to learn more about xylazine — there’s been minimal study of it in people — advocates are also trying to share the information they do have. Doctors and people who’ve been affected are giving presentations complete with images of gruesome wounds that have taken over people’s limbs, with stretches that have turned black — a sign of necrosis, or dead tissue — and where skin has sloughed off. They’re trading tips for treating wounds, which they stress can be healed, and swapping suggestions for how to help people through xylazine withdrawal.

At the outreach event, Stacy Parisella, a former trauma nurse, was cleaning a wound on the left wrist of 38-year-old Bret. A swollen lump was intruding into Bret’s hand, while at the center of it, a white ring of skin surrounded an open sore. This was actually an improvement. About two weeks ago, Bret said, he had gone to the hospital to get it treated.

In more than a decade of IV drug use, Bret said, he had never had any issues with wounds before, but in the past two years, “that was the second abscess I’ve gone to the hospital for.”

A concern is that people who use drugs — because they are often treated poorly by medical providers — won’t seek help for their wounds until they’ve advanced to a dangerous point. Bret, who lacks housing, said he ultimately went to the hospital because the wound on his wrist had gotten so swollen and painful he couldn’t move his hand. The hospital told him that if he hadn’t come in then, he would have lost his hand, he said.

Parisella told Bret that the wound looked OK for now, but that if the swelling got worse, or if it turned black, he needed to go to the hospital again.

Later that morning, Laurel LaCerra ran down from the park and grabbed Parisella for help. A man was sitting on the grass, with wounds overrunning both his shins. Some skin had turned black. The volunteers cleaned and wrapped the wounds, but suggested to the man he needed more advanced care at a hospital.

He told them he was worried about getting “sick” if he went to the hospital — being unable to use and entering withdrawal — but that he’d consider it.

wound care supplies at the outreach event at McPherson Square Park in Philadelphia
Wound care supplies at an outreach event at McPherson Square Park in Philadelphia. Andrew Joseph/STAT

The takeoff of xylazine in Philadelphia, which began in the mid-2010s, in some ways echoes how the sedative became cemented in the Puerto Rican drug supply in the 2000s. Known as “anestesia de caballo” (horse anesthetic), it introduced similar problems there, but didn’t attract broader attention, said Rafael Torruella, a social psychologist who runs a harm reduction organization called Intercambios. In a 2011 paper, Torruella warned that xylazine “could also emerge as an adulterant in other markets to the levels currently experienced in Puerto Rico.”

“At the time, I wanted more resources for researchers and harm reduction organizations in Puerto Rico to better get to know xylazine and its effects, and we did not get that,” he recalled.

But while xylazine predated the rise of fentanyl and related synthetic opioids in Puerto Rico, it’s been the reverse in the continental U.S. Fentanyl — in addition to being so potent that it’s helped drive the U.S. overdose crisis to record highs — provides a high that doesn’t last as long as the heroin it supplanted. For dealers looking to appeal to customers, xylazine seemed to offer a solution. It gave fentanyl “legs,” making the effect more durable, according to researchers who’ve studied the Philadelphia drug market. Still, many people have reported they don’t like tranq because it leaves them so sedated.

If Philadelphia is the epicenter of tranq dope now, there are signs it’s growing in other places. In North Carolina, for example, researchers and harm reduction groups noticed an increase in skin issues in 2020. At the time, they thought it was a behavioral effect — that a change in how people were using drugs was causing the wounds. But when they analyzed the local supply, they found xylazine, said Nabarun Dasgupta, a pharmacoepidemiologist at the University of North Carolina. It all clicked together.

Increasingly, groups from around the country, disturbed about wounds they’re starting to see, are turning to Dasgupta’s team to test their local drug supply. The analyses typically uncover xylazine in some of a community’s samples, but not all of them.

“It feels like it’s spreading, it definitely looks like it’s spreading,” Dasgupta said. “But there are pockets in the U.S. where we see it much more commonly than others.” He noted, for example, that despite what’s happening in Philadelphia, he’s heard that tranq is not nearly as prevalent in Pittsburgh, for unclear reasons.

Experts and advocates are still trying to understand just how dangerous xylazine is and how it works. There’s some evidence, for example, that it can interfere with people’s blood sugar and blood iron levels in potentially harmful ways.

Experts are not even sure what’s causing the associated wounds. Is xylazine somehow prompting people to pick at their skin? Many researchers believe it’s something to do with how the tranquilizer behaves in the body: Maybe it’s eliciting some errant inflammatory response. Perhaps it’s restricting blood flow so the wounds can’t heal.

But they are also trying to get the word out that these wounds should be treated differently than the infection-driven abscesses that doctors are more accustomed to. In the latter case, surgeons often amputate the digit or limb so that the infection doesn’t spread. But xylazine-related wounds seem able to be healed with proper care, a distinction that Dasgupta said many doctors aren’t aware of yet.

“It’s devastating and heartbreaking,” Dasgupta said about the possibility of people unnecessarily losing limbs.

Researchers are also debating what role xylazine plays in overdoses — essentially, if it makes fentanyl use even riskier. Notably, toxicologists are not seeing people die with just tranq in their systems. It’s almost always accompanied by fentanyl — as well as other substances, from cocaine to alcohol — which means it might still be the fentanyl that’s killing people. Some experts have speculated, however, that xylazine is such a powerful sedative that it could exacerbate the respiratory depression that opioid overdoses cause.

Regardless, xylazine is changing what recovering from overdose looks like. Someone who overdoses on tranq dope might start to breathe again after being given naloxone — which only works for opioids — but will still be passed out from the sedative. Responders unfamiliar with xylazine may reach for another dose of naloxone, but it still won’t wake the person up.

“When it was just fentanyl, it was more straightforward,” said Claire Zagorski, a Ph.D student at the University of Texas and a harm reduction paramedic. With xylazine and other drugs like benzodiazepines being cut into fentanyl, “these kinds of unholy mixtures that bring down the level of consciousness in different ways are really making the overdose response picture tricky.” (Advocates have pointed to xylazine and other contaminants in the drug supply to bolster their argument that the United States should offer people a safe supply of opioids, as Canada does.)

At a training session before the outreach event here in Philadelphia, Laurel LaCerra showed the volunteers how to use Narcan, but she suggested other strategies as well. Besides the naloxone, Savage Sisters has also started giving people who overdose oxygen, a combination the staff think is more effective against tranq dope. They’re teaching people how to roll someone who’s unresponsive but is not suffering from an opioid overdose into the “recovery position” — lying on their side with their head protected, a position that will keep their airway open and circulation flowing.

“This is really important right now with the tranq dope because people will be sedated,” Laurel LaCerra told the volunteers. “They’re not going to be as responsive as they used to be.”

Savage Sisters is also providing people who use drugs with cards they can give to medical providers that demand, “Test me for xylazine.” The cards offer suggestions that providers can try to treat the symptoms of xylazine withdrawal, which include anxiety. Whereas there are protocols for easing someone off illicit opioids, there is no such method for xylazine.

Before the volunteers headed out for the outreach event, Laurel LaCerra, who used to use drugs herself, emphasized that the group should not gawk at the people they were there to help.

“The wounds are horrific,” she said. “They are in so much pain.”

This story is part of a series on addiction in 2022, supported by a grant from the National Institute of Health Care Management. Previous articles covered the spike in overdose deaths among Black Americans, the Americans with Disabilities Act’s protection of people with addiction histories, and the debate about “safer supply” programs. 

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