A type of animal tranquilizer, xylazine, is now showing up in almost a third of fatal heroin and fentanyl overdoses in Philadelphia, according to research published today.
Xylazine is a non-opioid sedative, painkiller, and muscle relaxant that mimics the effects of opioids. It is normally used in veterinary medicine and the FDA has only approved it for animals, but is now being mixed with illegal drugs like fentanyl and heroin to increase the effects of the high.
The drug first became popular in Puerto Rico in the early 2000s where it was described as the “zombie drug” by the media due to its heavy sedating effect.
Xylazine can also dangerously lower blood pressure as well as impair central nervous system activity, breathing and heart rate – all of which can increase the risk of a fatal overdose.
It has been known to cause open skin ulcers when injected due to forms of bacteria and fungus that can be found in the drug that human bodies aren’t great at fighting.
And while it’s by no means as deadly as fentanyl or other opioids – which continue to claim thousands of lives – the growing prevalence of the tranquilizer in continental U.S. is causing experts to raise concerns.
The new study, published in the journal Injury Prevention, found that since 2010 unintentional overdoses that xylazine was present in has increased 15-fold in Philadelphia.
Using data from Philadelphia Medical Examiner’s Office for the years 2010 to 2019 the study found that between 2010 and 2015, xylazine was detected in only 2% of unintentional overdose deaths in which heroin and/or fentanyl also featured.
But by 2016 it was present in 11%, in 2018 it showed up in 18% of overdoses, and in 2019 that figure rose to 31%.
“Results from this study suggest that the opioid epidemic throughout the USA continues to evolve,” write the authors, adding that toxicology data from Philadelphia and other jurisdictions suggest that the prevalence of xylazine may be increasing across continental USA.
In New York the state senate passed a bill designating xylazine as a controlled substance in 2017, late last year Michigan Poison Control issued a warning regarding the abuse of xylazine and the Center for Forensic Research and Education also released a public health warning.
The study also points out that, based on the drug seizure data from Drug Enforcement Administration labs, xylazine is showing up more frequently in combined drug (polydrug) samples. Although, it’s worth noting the main drug detected is still heroin or fentanyl.
While no polydrug seizures contained xylazine between 2010 and 2013, this changed in 2015 when 5% of drugs tested turned up positive for traces of xylazine. In 2017 that figured jumped to 9% and in 2019 a quarter (25%) of drugs tested contained the tranquilizer.
And the study authors mention xylazine might be even more pervasive than we know.
“Prevalence of xylazine in overdose deaths may be underreported in the rest of continental USA as xylazine may not be consistently reported if forensic toxicology was not completed at death,” they wrote in their paper.
And while this latest study can’t answer if it’s the xylazine responsible for the fatal overdose or even why the use of xylazine is increasing in the local drug supply, the data does point to real risks for public health.
The problem is in most states xylazine isn’t a controlled substance so prescriptions aren’t tracked like they are for drugs like oxycodone. And as Christopher Moraff writes in Filter Magazine: “obtaining the drug requires only a veterinarian prescription, which is a piece of cake if you own a few horses, know someone who does, or just know which palms to grease.”
As such, the study authors call for stricter monitoring of the misuse of this substance across the U.S. and for it to be added to routine toxicology testing.
Meanwhile public health officials are more worried about the fact that it doesn’t respond to the overdose reversal drug Naloxone (Narcan) because it’s not an opioid, leaving responders helpless to prevent an overdose.