This Week’s Focus: Medetomidine

During the most recent NDEWS ideation meeting, several sites noted medetomidine, a veterinary α‑2 agonist emerging in their local illicit opioid supply.

Based on these signals presented during the meeting, NDEWS initiated additional follow‑up by way of an updated NDEWS Special Report and NDEWS Web Monitoring report to better characterize current trends.

Additionally, we highlight recent publications and reports that show medetomidine involvement in overdose and withdrawal presentations in Philadelphia, Pittsburgh, and Chicago; detection in 32% of opioid‑sold samples submitted to the NYC Drug Checking Program in 2025; and identification of the first confirmed case in Alabama via ED‑based toxicology testing.

These developments prompted this week’s deeper focus on medetomidine across the NDEWS network.

As always, we welcome your input.

From January 1, 2023 to January 31, 2026, there were 58 EMS encounters for nonfatal drug-related overdoses involving medetomidine. US counties with ≥ 10 encounters for medetomidine are reported below. Counties with < 10 EMS encounters are suppressed. View the entire Special Report from the weekly briefing, click here.

Click here to learn more about NDEWS Hotspot Alerts

Why are we reporting on this? Medetomidine is a potent alpha-2 adrenergic agonist identified as an adulterant in the illicit drug supply. This substance is frequently categorized in community discussions as "Tranq 2.0." Reddit discussions highlight growing alarm over this veterinary tranquilizer replacing or augmenting xylazine in fentanyl mixtures. Public health concerns are centered on the extreme potency of this substance—estimated to be 100 to 200 times stronger than xylazine—its ability to complicate overdose reversal, and its association with severe physical side effects that differ from traditional opioid or xylazine-only exposures. Reddit data indicate a significant upward trend in these discussions from January 2024 through late 2025, with a major activity peak in mid-2025 that aligns with high-profile public health alerts. 

What is Medetomidine? Medetomidine is a potent alpha-2 adrenergic agonist primarily used in veterinary medicine for sedation and analgesia. While medetomidine itself is not approved for human use, dexmedetomidine (the right-handed isomer) is used clinically in humans as a sedative. These substances are increasingly being identified as "cuts" in the fentanyl supply, often found in combination with xylazine and various synthetic opioids. In the illicit market, medetomidine is predominantly found in white powder form, though it has also been identified in liquid veterinary bottles, which some individuals attempt to process or separate from other substances.

Public Health Impacts Reddit discussants report significant adverse effects from medetomidine exposure, including profound and prolonged sedation that lasts longer than that of xylazine. Multiple commenters mention "blackout" states and deep unconsciousness that leave individuals vulnerable to physical harm or theft. Discussants frequently describe unique physical indicators such as muscle spasms, involuntary twitches, and hallucinations. A commonly reported concern is peripheral cyanosis—where the skin and extremities turn blue despite adequate oxygenation—which can mask actual oxygen deprivation during an overdose. Additionally, discussants report increased urination leading to severe dehydration, a higher risk of kidney damage, and unexpected cases of incontinence immediately following use.

How is it Being Discussed? Reddit commenters believe that medetomidine is rapidly replacing fentanyl or xylazine in certain regions, such as Philadelphia and Southeast Connecticut, with some predicting that fentanyl may eventually disappear from the supply due to the extreme potency of these tranquilizers. While the DEA notes that it is sourced as bulk powder from international suppliers in China and India, commenters acquire it locally through street-level "dope bags" or via couriers and mail services from decentralized online vendors. There is frequent discussion regarding the historical lack of specialized testing strips for medetomidine, though commercial test strips have recently begun to emerge in select public health programs. Discussants share consistently negative experiences with these drug mixtures containing medetomidine, noting that the sedative effects often overshadow the opioid euphoria, causing discussants to "pass out" immediately after intravenous injection. The substance is discussed alongside harm reduction strategies, emphasizing that while naloxone cannot reverse the effects of medetomidine itself, it remains critical for the opioids typically mixed with it, and alpha-2 agonists like tizanidine or clonidine are being used to manage the specific, severe withdrawal symptoms associated with it.

Click here to read more about NDEWS Online Monitoring.

A recently published study in the Journal of Addiction Medicine co-authored by NDEWS SAG Members Alex Krotulski and Barry Logan, NDEWS Sentinel Site Director Jeanmarie Peronne and NDEWS Community-Based Health Expert Alyssa Falise, researched the prevalence of medetomidine exposure among emergency department (ED) patients presenting with opioid and/or stimulant overdoses. Approximately 2.8% of patients had confirmed medetomidine exposure. Medetomidine was associated with increased odds of bradycardia within 24 hours of ED presentation (AOR: 4.0, 95% CI: 1.4, 10.6), and patients were more likely to require bag valve mask ventilation (20.5%) when compared to those without medetomidine (3.7%, p = 0.03) exposure. Read the full report here.

A recently published study in Harm Reduction Journal by Bradford et al. examined results from an ED‑based toxicology surveillance pilot in central Alabama. Among 31 participants with comprehensive testing, 25 were positive for xylazine. The study also documented the first confirmed medetomidine exposure in Alabama and detected exposure of o-methylfentanyl in 9 of the participants, all co‑detected with xylazine. Read the full report here.

A recently published advisory by the New York City Department of Health and Mental Hygiene discusses the latest on medetomidine withdrawal. The advisory warns that medetomidine is driving a severe withdrawal syndrome in NYC. In 2025, medetomidine appeared in 32% of opioid‑sold samples tested, nearly always with fentanyl. Read the full report here.

A recently published study in the Annals of Emergency Medicine by Lynch et al. reported on the emergence of medetomidine, a veterinary α‑2 agonist increasingly detected in the illicit fentanyl supply since its first identification in Maryland in 2022. The study described prolonged sedation, bradycardia, and biphasic blood pressure effects that persist after naloxone, and documents a rapid-onset withdrawal syndrome beginning 4–6 hours after last use. Many patients required intensive care, and diagnosis remains clinical due to limited testing availability. Read the full study here.

A recently published study in Forensic Science International by Vohra et al. examined medetomidine detection in Michigan samples from March 2024 to May 2025. Across 4,290 post‑mortem blood samples, 17 tested positive for medetomidine, with fentanyl co‑detected in 94.1% of cases and xylazine in 47.1%. In ante‑mortem oral fluid testing, 129 of 20,736 samples were positive, with fentanyl present in 97.7% of cases and both fentanyl and xylazine found together in 45.7%. The study confirmed medetomidine's frequent co-occurrence with fentanyl and xylazine in illicit drug mixtures. The findings highlight the need for enhanced surveillance and public health awareness.  Read the full study here.