Clinical Insight – Xylazine

The opioid epidemic in the United States has evolved over the years, with the substances and adulterants involved changing over time. Fentanyl has increasingly been found in the drug supply, contributing to a dramatic rise in overdose deaths.  More recently, the veterinary drug Xylazine has emerged as an additive to not only fentanyl but also other drugs of misuse, resulting in a growing number of overdose deaths nationwide. Given that many people are not aware that the drugs they are using contain Xylazine, these mixtures are particularly concerning. This edition of Clinical Insight explores what Xylazine is, its effects, and the challenges it presents within the illicit drug supply.

What is Xylazine?

• Xylazine is a veterinary drug used for sedation, pain relief, and muscle relaxation in large animals (e.g., horses, cattle). It is not approved for use in humans and currently is not a controlled substance.
• It is frequently added to other illicit substances, with fentanyl being the most common drug it is added to. It has also been found in heroin, and stimulants such as cocaine and methamphetamine. It has also been found mixed in with illicitly obtained oxycodone and alprazolam.
• Xylazine is increasingly being added to illicit drugs for multiple reasons. The cost of Xylazine is low, and it can be readily purchased on the Internet. With its low price, the use of Xylazine as an adulterant increases the profit for drug traffickers, who can reduce the amount of fentanyl or heroin used in the mixture, especially since Xylazine has opioid like effects. It is also attractive to some users who desire a longer high, since Xylazine not only enhances the effects of opioids but also has a longer lasting effect than a drug like fentanyl alone. Also, when combined with stimulants (known as a speedball), it can reduce the adverse effects and withdrawal symptoms of these drugs.
• Street names include: tranq, tranq dope, sleep-cut, Philly dope, zombie drug.

How is Xylazine used and what are its effects?

• Xylazine can be injected either into muscles or veins, and it can also be inhaled, ingested, or smoked.
• Effects from Xylazine can begin within minutes and last for 8 or more hours.
• Users of Xylazine experience similar effects as opioids.
• Signs and symptoms of Xylazine toxicity include sedation, slow breathing, dry mouth, low blood pressure, low heart rate, hypothermia, and high blood sugar levels. These symptoms are similar to those seen with opioid toxicity, making it difficult to distinguish between toxicity from opioids versus Xylazine.

Challenges encountered with Xylazine exposure

• Repeated Xylazine exposure can lead to physical dependence. As a result, withdrawal symptoms such as agitation or severe anxiety may occur when the dose is reduced, or the drug is discontinued. Users report these effects as being more severe than those experienced from heroin or methadone discontinuation. As Xylazine is not an opioid, standard medication assisted therapy, such as buprenorphine, methadone, or naltrexone, is not effective in managing Xylazine withdrawal.
• Long term use can result in chronic complications in various organs. Repeated exposure can lead to severe skin ulcerations that are distinctly different from other tissue infections, such as cellulitis or abscesses. For people who inject Xylazine, these ulcerations may develop in areas of the body away from the primary injection site. These wounds can lead to necrosis (rotting tissue), resulting in the possibility of amputations.
• Because Xylazine is often combined with fentanyl or other opioids, it increases the potential for fatal overdoses. Both drugs decrease respiratory function, which can be enhanced when used together.
• Naloxone is not effective in reversing the effects of Xylazine, since it is not an opioid. Because of this, Xylazine overdose may be suspected if signs of an opioid overdose show little improvement with naloxone administration. Naloxone is still administered in overdose situations though, as the naloxone can counteract the effects of any opioid present.

Xylazine testing strips and detection times

• To help combat the rising number of overdose deaths associated with the use of Xylazine-laced substances, testing strips are currently available for individuals to test substances for the presence of Xylazine.  These can be purchased online, and several states offer helpful guidance on how to use these strips on their websites.
• As a medication approved only for veterinary use, studies in humans are limited. Therefore, the detection time in human urine has not been established at this time.