The Food and Drug Administration on Tuesday announced it is cracking down on imports of xylazine, a non-opioid animal sedative growing in frequency and leaving users with gruesome, rotting wounds on their skin.

The FDA issued an import alert for all shipments of xylazine, subjecting packages to heightened FDA scrutiny and allowing agency staff to detain shipments of the drug, and the ingredients used to make it, to ensure they're intended for legitimate use.

Commonly referred to as "tranq," xylazine is only authorized in the U.S. for veterinary use and is often utilized by veterinarians to sedate large animals such as horses and deer. Now, tranq is being found mixed into the nation's illicit drugs and appearing in blood samples of overdose victims across the country.

When taken, xylazine can depress breathing, blood pressure, heart rate, and body temperature to critical levels, and injection "has been associated with severe, necrotic skin ulcerations that are distinctly different from other soft-tissue infections (e.g., cellulitis, abscesses) often associated with injection drug use," according to the FDA.

"The FDA remains concerned about the increasing prevalence of xylazine mixed with illicit drugs, and this action is one part of broader efforts the agency is undertaking to address this issue," FDA Commissioner Robert Califf said in a statement.

"We will continue to use all tools at our disposal and partner with the Drug Enforcement Administration and other federal, state, local agencies and stakeholders as appropriate to stem these illicit activities and protect public health," Califf said.

Xylazine has mostly been found mixed with heroin since its detection, increasing concerns regarding injections. While the drug is not an opioid in itself, the FDA warns its use may hinder the use of naloxone, the drug commonly used to reverse opioid overdoses.