According to a new study, researchers at the University of Washington School of Medicine have developed antibodies that may help reduce the harmful effects of xylazine, a veterinary sedative increasingly found in illicit fentanyl supplies. As part of the study, published in the peer-reviewed journal ACS Pharmacology & Translational Science, researchers identified an antibody from mice immunized with xylazine-targeting vaccines that, after being reengineered for improved stability and safety, prevented xylazine from reaching the brain and protected against severe reductions in heart rate and breathing.

“We want to move the field forward in generating therapeutics toward xylazine. This is the first step toward that,” said Dr. Jason Kang, the study’s lead author and a postdoctoral scholar in psychiatry and behavioural sciences at the University of Washington School of Medicine, in a press release.  

Xylazine, commonly known as “tranq,” has been increasingly found in illicit drug supplies across the U.S. and Canada, particularly alongside fentanyl, where it may be used to prolong fentanyl’s effects or consumed unknowingly. Like fentanyl, xylazine depresses the central nervous system and can slow breathing, heart rate and blood pressure, but its effects are not reversed by naloxone because it acts through a different molecular pathway.

“Xylazine is a major problem, and there aren’t a lot of great solutions to counteract its toxicity,” said Kang. In addition, he also noted that the drug epidemic in the U.S. has come in waves: first prescription opioids, then heroin and then synthetic fentanyl. Fentanyl is now the leading cause of drug overdose deaths in the U.S. According to Kang, the fourth wave has begun with the rise of mixed drug use. 

As part of future research, the researchers next plan to determine whether the antibody can reverse xylazine’s effects after they have begun and are also exploring antibodies that could simultaneously target both xylazine and fentanyl.