Xylazine (\

Xylazine has become one of the most common adulterants in the illicit fentanyl supply for several converging reasons rooted in economics, pharmacology, and availability. First, xylazine is inexpensive and relatively easy to obtain. It is not a federally controlled substance in the United States, which historically made it simpler to source than scheduled drugs. The Drug Enforcement Administration (DEA) and the Department of Homeland Security have identified China as a primary source of illicit xylazine, with the drug shipped directly to the United States or routed through Mexico. Second, xylazine extends the duration of fentanyl\\

Xylazine first appeared in the U.S. illicit drug supply in Puerto Rico in the early 2000s, where it was detected in a significant proportion of overdose deaths. By the mid-to-late 2010s, it had firmly established itself in the Philadelphia fentanyl market, where a 2021 analysis found xylazine present in 91% of samples of purported heroin or fentanyl collected through community drug checking services. Philadelphia became the epicenter of the xylazine crisis and was among the first cities to issue public health alerts. The drug then spread rapidly across the country. A seminal 2022 study by Friedman et al., published in Drug and Alcohol Dependence, documented that xylazine-positive overdose deaths grew nearly 20-fold between 2015 and 2020, with xylazine spreading \\

One of the most consistent and clinically significant findings in xylazine research is its near-universal co-occurrence with illicitly manufactured fentanyl. Data compiled across multiple jurisdictions shows that fentanyl was present in 98.4% of overdose deaths where xylazine was also detected. A study of overdose fatalities in Jefferson County, Alabama, found fentanyl in 100% of cases involving xylazine. The CDC\\

The management of xylazine-associated wounds requires an approach that diverges significantly from standard wound care practice. A multidisciplinary guidance document published in Open Forum Infectious Diseases in 2025 emphasizes that aggressive surgical debridement, which is standard for many chronic wounds, should be avoided in XAWs. Islands of healthy tissue within these wounds possess significant healing potential, and aggressive sharp debridement may paradoxically undermine tissue regeneration, enlarge the wound, and accelerate progression toward amputation. Instead, clinicians are advised to use limited sharp debridement, enzymatic debridement with collagenase-based agents to gently remove necrotic tissue, and a conservative approach that allows the wound bed to declare itself over time. Wound care protocols from the Philadelphia Department of Public Health recommend cleaning wounds with non-irritant solutions such as water or mild soap, avoiding hydrogen peroxide and alcohol. Primary dressings should be non-adherent and maintain wound moisture to support granulation, while secondary dressings absorb drainage. For wounds with suspected biofilm, topical antimicrobial agents including silver-based products or polyhexamethylene biguanide (PHMB) are applied directly to the wound bed following debridement. The American College of Surgeons has described xylazine wounds as \\

Naloxone (brand name Narcan) is an opioid antagonist that works by competitively binding to mu-opioid receptors, displacing opioid molecules and rapidly reversing respiratory depression caused by drugs like fentanyl, heroin, and morphine. Xylazine, however, is not an opioid. It acts on alpha-2 adrenergic receptors through an entirely separate pharmacological pathway. Because naloxone targets only opioid receptors, it has no effect whatsoever on the sedation, respiratory depression, bradycardia, or hypotension caused by xylazine. There is currently no FDA-approved reversal agent for xylazine that is safe for use in humans. In veterinary medicine, drugs such as yohimbine and tolazoline serve as alpha-2 antagonists to reverse xylazine\\

Managing a xylazine-involved overdose in the emergency department requires supportive care directed at multiple organ systems. The clinical toxidrome includes severe central nervous system depression, respiratory depression, miosis, bradycardia, and hypotension, with an initial transient hypertensive phase that may precede cardiovascular collapse. The New England Journal of Medicine published a clinical perspective in 2023 emphasizing the \\

Xylazine withdrawal is an increasingly recognized clinical syndrome that compounds the already difficult process of opioid withdrawal. Unlike opioid withdrawal, xylazine withdrawal symptoms are not alleviated by the administration of opioids or opioid agonist therapies such as methadone or buprenorphine, presenting a significant challenge for addiction medicine providers. Symptoms typically begin 6 to 12 hours after last use and include severe anxiety, irritability, restlessness, dysphoria, diaphoresis, tachycardia, and hypertension, reflecting a rebound surge in sympathetic nervous system activity following the removal of chronic alpha-2 adrenergic suppression. The acute phase generally lasts three to five days, though psychological symptoms including anxiety, depression, and intense cravings may persist for weeks. While no evidence-based protocols for xylazine withdrawal management have been established through clinical trials, the Center for Addiction Medicine and Policy (CAMP) at the University of Pennsylvania has published best practice guidelines recommending the use of alpha-2 adrenergic agonists such as clonidine, tizanidine, guanfacine, or dexmedetomidine to attenuate withdrawal symptoms, with a suggested taper over five to seven days. A case report published in the Journal of Addiction Medicine documented successful management of xylazine withdrawal in a hospitalized patient using a clonidine-based protocol. The recognition that patients in withdrawal from xylazine-adulterated fentanyl may be simultaneously experiencing opioid withdrawal and alpha-2 agonist withdrawal underscores the need for dual-targeted treatment strategies in clinical settings.

Fentanyl test strips (FTS) cannot detect xylazine. This is a fundamental limitation that users, clinicians, and harm reduction workers must understand. FTS are lateral flow immunoassays designed with antibodies that bind specifically to fentanyl and certain fentanyl analogs. They have no cross-reactivity with xylazine, which is a structurally unrelated compound acting on a different receptor system entirely. A fentanyl test strip will not change its result based on the presence or absence of xylazine in a sample. However, and this is a critical nuance, fentanyl test strips remain highly valuable in the context of xylazine-adulterated drugs precisely because of the co-occurrence data. With fentanyl present in over 98% of xylazine-positive samples, a positive FTS result on a drug sample strongly suggests the user is about to consume a product from the illicit fentanyl supply, which in many regions now routinely contains xylazine. Put simply: FTS cannot tell you whether xylazine is present, but a positive fentanyl result should prompt the assumption that xylazine may be co-present, especially in regions with known xylazine prevalence. This information can guide risk-reduction decisions such as using smaller amounts, having naloxone available, not using alone, and seeking wound care if skin lesions develop. Separate xylazine test strips (XTS) do exist, from several manufacturers, but their real-world performance has shown significant limitations, with one study finding sensitivity as low as 49.3% for low-concentration samples during community-based drug checking.

Detecting xylazine in the drug supply and in clinical specimens requires tools beyond standard fentanyl test strips. Several methods are available, each with different trade-offs in terms of cost, accuracy, speed, and accessibility. Xylazine test strips (XTS) are lateral flow immunoassays similar in design to fentanyl test strips. Commercial xylazine test strips detect xylazine in liquid or powder samples at a cutoff concentration of 1,000 ng/mL. In controlled laboratory conditions, these strips have shown sensitivity of 0.974 and specificity of 1.00 for samples at or above the cutoff concentration. However, real-world performance is more variable: a study of community drug checking in Los Angeles found that XTS detected xylazine in only 11% of residue samples where laboratory analysis confirmed xylazine in 44%, suggesting poor sensitivity for residue-level testing and low-concentration samples. SAMHSA has confirmed that federal grant funds may be used to purchase xylazine test strips, alongside fentanyl test strips, for harm reduction purposes. For definitive identification, laboratory methods including gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) are the gold standard but require specialized equipment, trained personnel, and turnaround times of seven to eight days. Fourier-transform infrared spectroscopy (FTIR) offers point-of-care drug checking with rapid results but is expensive and requires technical expertise. Chemical color reagent tests using reagents such as cobalt thiocyanate and Eosin Y can produce distinct color changes in the presence of xylazine, though they are less specific than immunoassay or chromatographic methods.

The U.S. government\\

Even as the public health system mobilizes against xylazine, a more potent alpha-2 adrenergic agonist has emerged in the illicit drug supply. Medetomidine, another veterinary sedative not approved for human use, began appearing in Philadelphia\\

The xylazine crisis carries specific and important implications for organizations distributing fentanyl test strips, including programs like Subcheck. Fentanyl test strips detect fentanyl in xylazine-adulterated samples but cannot detect xylazine itself. This means that an FTS-positive result on a sample from the current drug supply is simultaneously a fentanyl alert and an indirect signal of potential xylazine exposure. Programs should educate their communities on several key points. First, a positive fentanyl test strip result in 2026 should be understood in the context of a drug supply where xylazine, medetomidine, or other alpha-2 agonists may be co-present. Second, naloxone remains essential and should always be available, because it will reverse the fentanyl component of a mixed overdose even though it cannot address xylazine. Third, people who use drugs should be aware of xylazine wound risks and seek medical attention early for any skin changes, lesions, or slow-healing wounds, even at non-injection sites. Fourth, xylazine-specific test strips are available as a complementary tool but have meaningful sensitivity limitations, particularly for residue testing and low-concentration samples. Fifth, the emergence of medetomidine means the adulterant picture continues to change, and programs must stay current with local drug supply surveillance data. SAMHSA has confirmed that federal grant funds may be used to purchase both fentanyl and xylazine test strips, supporting programs that wish to offer dual testing capabilities. The overarching message for harm reduction programming is that fentanyl test strips remain a vital first line of drug checking even in an era of non-opioid adulterants, because the fentanyl-xylazine nexus means detecting one substance provides actionable intelligence about the other.

The presence of xylazine in the drug supply requires an expanded harm reduction toolkit that goes beyond traditional opioid-focused interventions. Organizations and individuals should adopt several evidence-based strategies. Never use alone: xylazine\\

Despite rapid advances in understanding xylazine\\