The drug xylazine has been in the news recently as a dangerous substance commonly mixed with heroin, fentanyl, and other drugs. Xylazine is not an opioid nor is it currently a controlled substance, which presents unique challenges for legal and public health professionals. This post, co-written by SOG faculty members Kirsten Leloudis and Phil Dixon, examines the legal and public health issues surrounding the drug.
What is Xylazine? Xylazine is a non-opioid sedative or tranquilizer that was first developed in 1962 by the pharmaceutical company Bayer. Xylazine was initially investigated for potential human use as an analgesic, sleeping aid, and anesthetic but was found to have concerning side effects, including severe hypotension and depression of the central nervous system. While xylazine never received approval by the United States Food and Drug Administration (“FDA”) for use in humans, the drug has been approved by the FDA for use in veterinary medicine since 1972. Xylazine in liquid solution form is sold for veterinary use under the trade names Rompun® and AnaSed®. Xylazine may also be referred to by its slang nickname, “tranq.”
Xylazine is typically injected but can also be swallowed or sniffed. Although xylazine can be taken on its own, it is more frequently mixed with fentanyl, heroin, or cocaine. The drug is relatively inexpensive and is often combined with these pricier substances as a low-cost way to increase drug effects or increase dealers’ profits from substances that are typically sold by weight. Because the “cutting” of more expensive drugs with xylazine may occur at the retail level, people who use drugs may be unaware that the substances they have purchased contain xylazine.
Health Risks of Xylazine. Information about xylazine’s toxicity in humans is limited, but law enforcement, health care providers, and public health agencies continue to learn more about its effects through case reports. The United States Centers for Disease Control and Prevention (“CDC”) advises that xylazine can cause sedation, difficulty breathing, dangerously low blood pressure, slowed heart rate, hypothermia, and death. Repeated injection of xylazine is associated with unique soft tissue wounds, characterized in part by necrotic tissue, that may develop away from the injection site. These wounds can easily become infected and, if untreated, may result in limb amputation. Repeated use can also result in xylazine dependence and withdrawal.
Although the effects of xylazine are similar to those caused by opioids, xylazine is not part of the opioid class of drugs. As a result, naloxone—one of public health’s most relied upon tools in responding to the opioid crisis—does not reverse the effects of xylazine. Similarly, medications such as methadone, buprenorphine, and naltrexone that are used for treatment of opioid use disorder may be ineffective for managing the symptoms of xylazine withdrawal.
Note: Although naloxone may be ineffective at reversing the effects of xylazine, the CDC currently recommends administering naloxone in response to any suspected overdose and calling 911. Naloxone is effective for reversing the effects of other drugs that are commonly mixed with and used alongside xylazine and administration of naloxone may help save the life of a person who is overdosing. Since xylazine also causes breathing to slow, CDC currently recommends giving rescue breaths to someone who has used xylazine. Please see the CDC recommendations linked within this post or contact a health care provider, as appropriate, for additional questions on xylazine overdose treatment.
How Big of a Problem is This? According to a 2022 report by the United States Drug Enforcement Agency (“DEA”), the prevalence of xylazine in the nation’s illicit drug supply has skyrocketed since 2020. In 2021, the largest increase in terms of prevalence of the drug (193%) was in the Southern U.S. That region also saw a 1,127% increase in xylazine-positive overdose deaths between 2020 and 2021. The DEA notes in its report that the death count is not complete and likely under-represents the actual number of xylazine-positive overdose deaths. For 2022, the DEA reported that 23% of fentanyl powder and 7% of fentanyl pills seized by the agency contained xylazine.
In February 2023, the FDA issued an import alert for xylazine, which allows for the administrative seizure of the substance. According to the DEA, the drug still manages to enter the country by way of illegal drug trafficking and web-based sales that allow xylazine to be purchased and shipped from another country. The DEA has found that xylazine can be purchased online from China for a price of between $6 and $20 per kilogram without requiring any proof that the buyer intends to use the drug for veterinary purposes.
Testing for Xylazine. Routine drug testing kits and drug screens, such as immunoassay toxicology screens, do not readily detect xylazine. Health care professionals attempting to treat an overdosing patient may therefore not easily discover the presence of the drug, which can result in misdiagnosis as an opioid overdose and consequent ineffective treatment. The FDA has explained that even if appropriate screening methods are used, xylazine can be hard to identify because it has a half-life of only 25 to 30 minutes, which means it is quickly eliminated from the body.
Out in the field, many people using drugs have begun relying on drug testing kits to protect against inadvertent fentanyl consumption and to verify the identity and purity of a drug as a way to avoid accidental overdose. North Carolina removed drug testing kits from the definition of drug paraphernalia in 2019 in recognition of the value of such testing. See G.S. 90-113.22(d). Like with drug screens, most routine drug testing kits do not test for xylazine and will not detect its presence. Testing kits developed specifically for xylazine do exist, but may not yet be widely available in all communities.
Xylazine is Currently Not a Controlled Substance. Xylazine is currently not an illegal controlled substance under North Carolina or federal law. The FDA regulations limit distribution of the drug to licensed veterinarians, but that seems to be it as far as national regulation. 21 C.F.R. 522.2662. There is a bill aiming to change that on the federal level, here. A coalition of 39 state attorneys general, including North Carolina’s, have urged Congress to pass the proposed bill. If passed in its current iteration, the bill would schedule xylazine as a Schedule III controlled substance (including all salts, isomers, and derivatives of the drug). On the state level, some places have acted to criminalize and schedule the substance, but there is no similar legislation pending in North Carolina at the time of this writing. Even if the federal bill were to become law, state officials would lack the ability to enforce such a ban, absent a similar prohibition under state law.
Xylazine is Not an Analogue Controlled Substance. Both federal and state criminal law prohibit the illicit use and distribution of analogue controlled substances—drugs designed to mimic the effects of controlled substances, but which are chemically distinct from actual controlled substances. The state and federal definitions of an analogue controlled substance mirror each other. See G.S. 90-87(5a) and 21 U.S.C. 802(32). Both laws define a controlled substance analogue as a substance chemically similar in structure to an existing Schedule I or II drug and intended for human consumption, which either mimics the effects of one of those types of controlled substances or which is intended to or represented as having such a mimicking effect. Xylazine is an analogue of another drug, clonidine, but that drug is also not an illegal controlled substance (much less a Schedule I or II drug). Clonidine and xylazine belong to a class of drugs known as alpha 2-adrenergic agonists, which are not chemically similar in structure to existing Schedule I or II drugs, even if they may share similar effects. For this reason, it seems unlikely that xylazine would qualify as an analogue controlled substance. Simply put, no provision of current federal or North Carolina criminal law prohibits xylazine as an illegal drug.
Resources. For more information about xylazine, health risks, and federal guidance for legal and public health professionals, please see these materials from the FDA, CDC, DEA, and Substance Abuse and Mental Health Services Administration.
If readers have questions, comments, or concerns for us, we can be reached at kirsten@sog.unc.edu and dixon@sog.unc.edu.