Tuesday, the Food and Drug Administration issued a notice urging health care providers to be “cautious” with a medication for animals that has infiltrated the illegal drug supply and been linked to overdoses.
The FDA has authorized the use of xylazine as a sedative and pain treatment for animals. It is not licensed for human usage and can have “serious and life-threatening adverse effects that resemble those usually linked with opiate use.”
In a letter to interested parties, the FDA stated that xylazine was typically detected in combination with opioids such as fentanyl or heroin, or infrequently with stimulants such as methamphetamine and cocaine. People who are exposed to xylazine “may not be aware” that it is present in their medicine supply, according to the administration.
The alert cautioned that it can be “difficult to distinguish” xylazine overdoses from opioid overdoses due to the similarity of certain adverse effects, including respiratory depression.
Xylazine is undetectable by standard toxicological tests. Hypothermia, hypotension, and “severe, necrotic skin ulcerations” are other side effects that can result from repeated injections of xylazine.
Despite having similar side effects and appearance, xylazine has different effects on the human body than opioids.
According to Claire Zagorski, a paramedic, program director, and harm reduction teacher with the Texas Opioid Training Initiative at the University of Texas in Austin, Xylazine has a wide-ranging sedative effect. “It reduces brain activity, decreases heart rate, and slows breathing, but opioids have this unique property where they may actually stop breathing. Xylazine doesn’t act in quite the same manner…. We aren’t seeing the abrupt deadly overdoses associated with fentanyl.”
Because xylazine is not an opioid, the FDA is unsure if naloxone, a drug that reverses opioid overdoses, can reverse the negative effects of xylazine.
“(Xylazine overdoses) are very definitely not reversible with naloxone,” Zagorski stated, adding that just one study suggests that naloxone could correct such an overdose. In 1984, the investigation was conducted on chicks.
Zagorski also cautioned that fentanyl testing strips, which may detect the presence of the potent opioid in illicit compounds, do not work with xylazine. According to clinical professor Jeffrey Bratberg of the University of Rhode Island College, xylazine test strips are currently being developed.