Xylazine, an animal tranquilizer is now a trending drug added to the unfortunate list of harmful substances that affect the city of Philadelphia. According to a research published Tuesday in the journal Injury Prevention, the drug is included in over a third of fatal heroin and fentanyl overdoses in Philadelphia.
Although the tranquilizer drug is not considered an opioid, it is often found mixed with the opioids heroin or fentanyl, a combination sometimes referred to as “tranq”, “tranq dope” or “sleep cut.”
According to a Rachel Rettner report for Live Science, the researchers found that detection of xylazine during post-mortem exams has increased sharply over the past decade among people who have died from opioid overdoses in Philadelphia.
The findings suggest that “the opioid epidemic throughout the USA continues to evolve,” the authors wrote. They say that overdose deaths involving the animal tranquilizer may be underreported in the country because labs do not always test for it. The authors call for increased monitoring of xylazine abuse in the U.S., as well as its health consequences.
Xylazine is a sedative used in veterinary medicine, particularly in horses. In the U.S., it is not approved for use in humans due to its side effects which can include low blood pressure and a slow heart rate.
In the study, the researchers analyzed data on overdose deaths in Philadelphia from 2010 to 2019. Specifically, they examined unintentional deaths involving heroin or fentanyl, which are both types of opioids.
The researchers found that, between 2010 and 2015, xylazine was detected in just 2% of these overdose deaths. But by 2019, that figure had jumped to 31%.
Another alarming fact is that data on illegal drug seizures from the U.S. Drug Enforcement Administration suggest that xylazine is increasingly appearing in “polydrug” samples, which contain heroin or fentanyl along with other drugs. Between 2010 and 2013, none of the polydrug samples that were tested in the agency’s labs contained xylazine, but by 2019, 25% contained the drug.
Despite studies on the health effects of xylazine combined with opioids are limited, some research suggests that the mixture may increase the risk of opioid overdose death.
However, the researchers note that their study could not determine which drug or combination of drugs was involved in the Philadelphia overdose deaths.
It is also unclear exactly why xylazine is being added to the U.S. drug supply and whether the people who overdosed were conscious of taking that drug. Some focus groups in Philadelphia have found that people who use illegal drugs report that xylazine makes the effects of opioids last longer, the authors said.
The authors concluded that “further study is needed to understand the synergistic effects of fentanyl and xylazine use by humans and to better contextualize the reasons for its use in the USA.”