AUSTIN (KXAN) — Austin’s chief medical officer has a new concern about what could be in local street drugs: an animal tranquilizer called xylazine. Xylazine is FDA-approved as a veterinary medicine.

“When it transitions into human beings, there’s a profound effect. There’s coma, there’s a low heart rate that affects primarily also the respiratory effort, which is ultimately what leads to death,” said Dr. Mark Escott, Austin’s chief medical officer.

A new study found xylazine is also linked to increased risk of tissue infection and resistance to naloxone, or Narcan, which is an antidote to overdoses.

Researchers from the University of California, Los Angeles, Columbia University and the University of Alabama also said data suggests xylazine “increases the short duration of fentanyl” and “adds euphoria.”

Dr. Escott initially suspected xylazine was behind the three fatal overdoses on Sixth Street earlier this month, but the medical examiner told KXAN Friday the drug was not detected in those cases or any other deaths, so far.

The examiner said the final toxicology reports had not yet been completed, but the three deaths had been tested for xylazine, adding their toxicology testing would detect the drug, if present.

The Austin Police Department said it’s still waiting for test results from narcotics seized two weeks ago.

“We certainly have some concern from our hospital systems, and there’s some additional testing going on on some of the patients they’ve been seeing, but nothing conclusive yet,” Escott said.

The new study found in 2015 xylazine was part of 0.36% of fatal overdoses. That jumped to 6.7% in 2020.

Researchers also said in 98% of xylazine-involved deaths, fentanyl was also found, “suggesting a strong link.”

Escott said based on historic drug travel patterns, he expects the drug additive to show up in Austin.

“From our perspective, it’s a matter of when and not if that we’re going to see the xylazine enter here,” he said.