The Biden administration released a national response plan Tuesday to address the emerging threat of fentanyl combined with xylazine in the U.S. 

The White House Office of National Drug Control Policy (ONDCP) plan coordinates a whole-of-government response against the threat. 

The drug has been detected in nearly every state in the country and data from the Centers for Disease Control and Prevention (CDC) have continued to show an increase in xylazine-related overdose deaths. 

The monthly percentage of illegally manufactured fentanyl-involved deaths with xylazine detected increased 276% from January 2019 through June 2022.

But, what is xylazine? 

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Xylazine is a non-opioid tranquilizer approved by the Food and Drug Administration for veterinary use but not for human use. 

Also known as "Tranq," xylazine is a central nervous system depressant and powerful sedative. 

It can cause drowsiness and amnesia, and slow breathing, heart rate and blood pressure to dangerously low levels.

Repeated xylazine use is also associated with skin ulcers, abscesses and related complications.

Those who inject drug mixtures containing xylazine also can develop necrosis – the rotting of human tissue – that may lead to amputation.

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Taking opioids with the drug or other central nervous system depressants increases the risk of a life-threatening overdose.

People report using xylazine or xylazine-containing drugs by injecting, snorting, swallowing or inhaling.

Studies have shown that people exposed to xylazine, often knowingly or unknowingly, used it in combination with other drugs – particularly illicit fentanyl.

In the event of a suspected xylazine overdose, experts recommend giving the opioid overdose reversal medication naloxone because xylazine is frequently combined with opioids. 

However, because the drug is not an opioid, naloxone does not address the impact of xylazine on breathing. As a result, experts are concerned that a growing prevalence of xylazine in the illicit opioid supply may render naloxone less effective for some overdoses.

"Xylazine is making the deadliest drug threat our country has ever faced, fentanyl, even deadlier," U.S. Drug Enforcement Administration Administrator Anne Milgram said in a statement. "DEA has seized xylazine and fentanyl mixtures in 48 of 50 states. The DEA Laboratory System is reporting that in 2022 approximately 23% of fentanyl powder and 7% of fentanyl pills seized by the DEA contained xylazine."