NASHVILLE, Tenn. (WKRN) — A Nashville-based healthcare testing lab reported an increase in human samples testing positive for a tranquilizer meant for large animals in a recent study.

Aegis Sciences Corporation published a study showing a widespread presence of xylazine in patient samples across the United States, including in Middle Tennessee.

Xylazine, which is also called “tranq,” is not approved for humans, but people are using it to extend their drug high. According to experts, it can be snorted, injected, smoked, or pressed into pills.

Xylazine is not an opioid, but it does have many similar side effects, including slowed heart rate and breathing. Xylazine does not respond to the overdose-reversing drug, naloxone, increasing the chances of death.

“The biggest concern is the overdose risk,” Dr. Andrew Holt, a clinical pharmacist for Aegis Sciences Corporation, said.

In addition, tranq can cause serious skin infections which can lead to gangrene and amputations.

Holt told News 2, from early 2021 to late 2022, the lab saw the number of positive xylazine drug tests triple from more than 400 to more than 1,300. However, those numbers likely underrepresent the presence of xylazine, because Aegis Sciences Corporation only tests for the drug upon request.

According to the study, 96% of the positive xylazine samples tested by Aegis Sciences Corporation were also positive for fentanyl. Other common substances detected with xylazine were cocaine, meth, naloxone, and buprenorphine.

Considering the growing popularity of the drug, Holt said it’s important to only take pills obtained from a pharmacy to avoid unknowingly ingesting xylazine.

“It’s difficult for someone to look at a drug product that they’re purchasing or given or whatever and tell whether xylazine is present,” Holt said. “A lot of this is pressed into pills, counterfeit pills that look like prescription pills.”

To read the full study, click here.