In Boston and across the state, an animal tranquilizer called xylazine is being mixed with opioids and is intensifying concerns surrounding the overdose epidemic in Massachusetts.“It’s all over Massachusetts,” said Julie Burns, the president and CEO of RIZE Massachusetts, a public-private partnership dedicated to funding solutions to end the overdose crisis.“It's really unclear what it's going to do over the long term, but it does have some pretty devastating short-term effects to a person who's using it,” she said. “Wounds, all kinds of abscesses, sores on their skin, as well as it doesn't respond to Narcan.”Narcan is the brand name for naloxone, a medicated nasal spray that can be used to reverse an opioid overdose.It is unclear how much xylazine is in Massachusetts, or whether more is on the way, but hundreds of drug samples from a statewide testing program show it has been present in Massachusetts since at least 2020.In June 2022, xylazine was present in 28 percent of drug samples tested, In the first half of 2022, toxicology tests found xylazine in 5 percent of all people who died of an opioid overdose in the first half of 2022. It’s generally been mixed into other drugs that are sold as something else, such as fentanyl, heroin or cocaine, and users often don’t know it’s there.“We started to notice xylazine in the drug supply in Brockton probably about a year and a half ago definitively, but it probably was in the supply somewhat before that,” said Allyson Pinkhover, the director of substance use services at Brockton Neighborhood Health Center. Pinkhover said xylazine can delay the peak of a high, and can also delay an overdose.“Naloxone doesn't necessarily work to reverse an overdose, if somebody has ingested xylazine,” she said. “And so we worry that there might be an increase in overdoses.” Additionally, there are wounds the drug can cause. They can appear anywhere, not necessarily in the spot where someone is injecting drugs. Staff at the health center has said wounds related to xylazine are different to treat than other infections. “We saw a lot more skin infections, lesions and abscesses,” said Kelly Celata, the homeless services program manager at Brockton Neighborhood Health Center.The health center has a mobile services unit that travels across the city to offer walk-in care to patients. They're seeing first-hand the after-effects of xylazine, which is also known as tranq.“Our LPN and phlebotomist ordered a bunch of specialty wound care supplies to treat lesions and abscesses that we think are a result of xylazine being in the local drug supply,” Celata said. As part of its harm reduction strategies, the center is also testing street drugs on the road and back at their building, using a spectrometer machine.The results? Xylazine has been found in a third of the fentanyl samples tested in Brockton since August 2021.“It’s a great tool for what we call advanced drug checking,” Pinkhover said. “A lot of people have done some drug checking with fentanyl test strips in the past. And so this is something that goes beyond that and allows us to not just look for fentanyl, but different things that might be in a sample as a whole.” But Pinkhover is worried about the overall lack of screening for xylazine.“I think as a whole, the medical community is not particularly well equipped to deal with the xylazine at this point,” she said.Being aware and prepared is about saving lives, she said.“We always say that goal number one is stay alive. And goal number two is any positive change. Those are the things that we focus on in harm reduction,” Pinkhover said.Although the drug is increasing in prevalence in Massachusetts, xylazine is not new overall; it has been in the drug supply in Puerto Rico for more than a decade, and has been showing up in Philadelphia for years.