The US Medicines Agency is concerned about a “growing public health problem”. US health authorities announced on Tuesday February 28 measures to better control the import of xylazine, an animal tranquilizer increasingly found in drugs taken by humans, with devastating consequences.

Also nicknamed “tranq” or “zombie drug”, xylazine is increasingly used in the United States in combination with other drugs, such as fentanyl, heroin, methamphetamine and cocaine. Consumers are not necessarily aware of its presence in their drug.

Authorized since 1972 by the American Medicines Agency (FDA) as a sedative and veterinary analgesic, xylazine is used to calm animals, for example horses, in order to facilitate their management or against pain. But in humans, it can slow “breathing, blood pressure, heart rate” and reduce “body temperature to critical levels,” warns the FDA.

Worse still, consuming it can cause “skin sores and patches of dead, rotting skin,” including places other than the injection site, she added. These wounds “can easily become infected and, without treatment, lead to amputation.”

Up to 26% of fatal overdoses in Pennsylvania

Of increased concern: Naloxone, an antidote that can resuscitate a person in the midst of an opiate-related overdose, is not effective against the effects of xylazine. Experts still recommend trying to give naloxone to anyone who overdoses, as the two drugs can be taken together. It is difficult to tell the difference between an overdose caused by xylazine, or an opiate like fentanyl.

It is particularly widespread in the northeast of the country. According to a study, 26% of fatal overdoses in Pennsylvania in 2020 involved xylazine, and 20% in Maryland, a neighboring state of the capital Washington.

The “import alert” launched will place xylazine shipments “under increased surveillance by the FDA”, which may seize them in the event of non-compliance with the law. In particular, the FDA will ensure that the pharmaceutical ingredients used to make xylazine and the finished product are “properly labeled, unadulterated, and for legitimate veterinary use.”

“This action is part of a larger effort by the agency to address this issue,” FDA chief Robert Califf said in the statement. The agency says it is working with partners at the local and federal level, and has promised to keep the public informed of the progress of the work being undertaken.