As the veterinary sedative medetomidine displaces xylazine in Philadelphia and parts of the Northeast and Midwest, a single case report and a transport study add detail to a withdrawal syndrome that can require intensive care.

By PDMPNews Staff

This article is written for clinicians, public health officials and program administrators. It reports published findings and does not offer treatment, dosing or medical guidance.

From adulterant to clinical problem

Medetomidine is a veterinary alpha-2 agonist sedative. It is not approved for human use, and it is not federally controlled. A March 2026 Drug Enforcement Administration (DEA) fact sheet states plainly: “Medetomidine and dexmedetomidine are not controlled under the Controlled Substances Act.”

On April 2, 2026, the Centers for Disease Control and Prevention (CDC), with the Office of National Drug Control Policy (ONDCP), issued a national Health Alert Network (HAN) advisory, HAN-00527. Its central warning: “Stopping medetomidine following regular use can precipitate a severe withdrawal syndrome, similar to clonidine withdrawal, that can require emergency or intensive care.”

CDC’s figures show how fast the substance has spread. Medetomidine reports in the National Forensic Laboratory Information System (NFLIS), which tracks drugs identified in law enforcement seizures, rose from 247 in 2023 to 2,616 in 2024 and 8,233 in 2025. In 2025, 52% of those reports came from the Northeast, 31% from the Midwest, 17% from the South and less than 1% from the West. CDC also notes that street samples lack the preservatives found in medical or veterinary products, findings that “suggest medetomidine is being synthesized in clandestine laboratories.”

Where it is displacing xylazine

The claim that medetomidine is replacing xylazine holds strongly in some places and not in others.

  • Philadelphia: In June 2025, the Philadelphia Department of Public Health (PDPH) reported that “medetomidine is more prevalent in Philadelphia’s illicit fentanyl supply than xylazine,” finding it in more than 70% of illicit fentanyl samples compared with 30% to 40% for xylazine. By the first quarter of 2026, PDPH reported medetomidine in 90% of samples where fentanyl was the primary drug.
  • Withdrawal visits: PDPH reported in June 2026 that “since medetomidine was first detected in Philadelphia in April 2024, emergency room visits for withdrawal have increased by 291%.”
  • Sentinel drug-checking sites: From July to December 2025, CDC reports that 10 of 20 CDC-supported sentinel sites detected medetomidine in almost 35% of opioid-positive samples, while Western sites ranged from 2% to 8%.

The fair summary is regional dominance, not nationwide replacement. DEA reports that in 2025, fentanyl and xylazine were the substances most often found alongside medetomidine.

What withdrawal looks like

According to CDC, withdrawal begins within hours and peaks 18 to 36 hours after last use. Reported features include rapid heart rate (tachycardia), severe high blood pressure, fluctuating alertness and vomiting. CDC says withdrawal has been associated with non-ST-elevation myocardial infarction (NSTEMI) and posterior reversible encephalopathy syndrome (PRES). Medetomidine does not appear on hospital rapid drug screens and is rapidly metabolized, so it can be hard to detect by the time withdrawal starts. Unlike xylazine, CDC says, medetomidine use “does not seem to be associated with development of wounds.”

The May 2025 issue of CDC’s Morbidity and Mortality Weekly Report (MMWR) documented the scale of the problem. In Philadelphia, 165 hospitalized patients with suspected medetomidine withdrawal were identified between September 2024 and January 2025; 91% required intensive care unit (ICU) care and 24% were intubated. In Pittsburgh, clinicians described 23 patients and noted that “a rapid clinical test for medetomidine is not available.”

Study one: a single case of stress cardiomyopathy

A case report from Penn Medicine, published online October 20, 2026, in Substance Use & Addiction Journal, describes a 51-year-old woman with opioid use disorder who came to the emergency department concerned about withdrawal from fentanyl and medetomidine. PDMPNews reviewed only the published abstract; the full text was not accessible.

According to the abstract:

  • She received a dexmedetomidine infusion for medetomidine withdrawal. “Shortly after coming off” the infusion, she developed acute ST-segment changes, elevated troponin and regional wall-motion abnormalities on echocardiogram.
  • Coronary angiography showed no blockage.
  • Her cardiac lab values normalized days later, and heart function improved on follow-up imaging.
  • The authors conclude this “signifies a temporary stress cardiomyopathy, likely from a2 agonist withdrawal.”

This is one patient. A case report cannot establish cause, and the abstract does not say whether medetomidine exposure was confirmed by laboratory testing. The timing ties the event to the end of a hospital alpha-2 agonist infusion, so it describes alpha-2 agonist withdrawal broadly, not street medetomidine alone. The patient was also in opioid withdrawal. The authors themselves note that documentation of this phenomenon is limited.

Study two: transport outcomes in 182 patients

A retrospective case series from the Temple Transport Team, published September 9, 2026, in the Western Journal of Emergency Medicine, reviewed patients transported between facilities on dexmedetomidine infusions for presumed alpha-2 agonist withdrawal from January through June 2025.

  • Researchers identified 217 patients; 182 had complete vital-sign data.
  • Mean arterial pressure (MAP) fell modestly, from 122.1 to 118.3 mm Hg. Heart rate changed little, from 104.9 to 103.6 beats per minute.
  • The authors report: “No cases of severe hypotension or clinically significant bradycardia requiring intervention were documented.”
  • No patient was intubated during transport.

The authors list important limits: a single agency, no control group, many co-medications and non-standardized timing of vital signs. Transports averaged about 16 minutes, and withdrawal was presumed rather than laboratory-confirmed. The study measures stability during transport, not treatment effectiveness or withdrawal severity.

The paper also raises an operational point. In Pennsylvania, the authors write, these transports currently require at least a prehospital registered nurse (RN) and fall outside advanced life support (ALS) scope, which they say has delayed transfers and increased emergency department boarding.

Reading the two together

Taken side by side, and as PDMPNews analysis rather than either paper’s claim, the studies point to the same place: the period around and after alpha-2 agonist therapy is a point of clinical attention that the evidence has only begun to describe. PDPH’s own June 2026 guidance acknowledges that the literature “is limited to retrospective cohort studies, case studies, and expert opinion.”

A patchwork of state law

  • Federal: not controlled.
  • South Dakota: House Bill 1169 (2026) classifies medetomidine as a Schedule III controlled substance, with veterinary exemptions.
  • Virginia: Chapter 447 (2026) makes manufacturing or distributing medetomidine or xylazine “when intended for human consumption” a felony and possession a misdemeanor. This criminalizes conduct without scheduling the drug.
  • Pennsylvania: Schedule III bills (House Bill 2529 and Senate Bill 866) have each passed one chamber but are not law.
  • Ohio: the Board of Pharmacy has proposed Schedule III placement; the outcome is not yet known.

Why it matters for PDMPs

A prescription drug monitoring program (PDMP) tracks controlled substance prescriptions dispensed in a state. Illicit medetomidine is invisible to it. The drug is not federally controlled and is not prescribed to people, and even where a state schedules it, street supply is never dispensed or reported.

What a PDMP can show is part of the treatment footprint, such as pharmacy-dispensed buprenorphine and other scheduled medications. For a clinician reviewing a patient in medetomidine withdrawal, that creates an uneven picture: an opioid history may be visible, while the alpha-2 agonist dependence driving the acute danger is not.

The data that does capture medetomidine lives elsewhere: drug checking, NFLIS seizure data, DEA toxicology testing, syndromic emergency department surveillance and wastewater testing, all cited in CDC’s advisory. In PDMPNews’s view, that argues for states to consider how PDMP data, drug-checking results and syndromic surveillance can inform one another within each state’s legal limits. No single dataset sees this problem whole.

What to watch

Key markers ahead include action on the Pennsylvania bills, Ohio’s final rule and any prospective studies of withdrawal management and transport.

References

Centers for Disease Control and Prevention. (2024, May 7). Prescription drug monitoring programs (PDMPs). https://www.cdc.gov/overdose-prevention/php/interventions/prescription-drug-monitoring-programs.html

Centers for Disease Control and Prevention. (2026, April 2). Medetomidine in the U.S. illegal fentanyl supply increasing risk for overdose and severe withdrawal syndrome (CDCHAN-00527). Health Alert Network. https://www.cdc.gov/han/php/notices/han00527.html

Drug Enforcement Administration, Diversion Control Division. (2026, March). Medetomidine (including dexmedetomidine) [Drug & chemical information]. https://deadiversion.usdoj.gov/drug_chem_info/medetomidine/Medetomidine.pdf

Goldstein, S., Zahustecher, N., Isenberg, D., Rosen, E., & Bennett, C. (2026). Hemodynamic effects of interfacility dexmedetomidine infusions during transport of patients with alpha-2-adrenergic agonist withdrawal. Western Journal of Emergency Medicine, 27(5), 1327-1330. https://doi.org/10.5811/westjem.62953 (PubMed: https://pubmed.ncbi.nlm.nih.gov/42900939/)

Huo, S., London, K., Murphy, L., et al. (2025). Notes from the field: Suspected medetomidine withdrawal syndrome among fentanyl-exposed patients, Philadelphia, Pennsylvania, September 2024-January 2025. MMWR. Morbidity and Mortality Weekly Report, 74(15), 266-268. https://doi.org/10.15585/mmwr.mm7415a2

Krishna, D., Bennett, B., Lin, A., & Spadaro, A. (2026). Takotsubo cardiomyopathy associated with severe medetomidine withdrawal: A case report. Substance Use & Addiction Journal. Advance online publication. https://doi.org/10.1177/29767342261493888 (PubMed: https://pubmed.ncbi.nlm.nih.gov/42899488/)

Ostrowski, S. J., Tamama, K., Trautman, W. J., Stratton, D. L., & Lynch, M. J. (2025). Notes from the field: Severe medetomidine withdrawal syndrome in patients using illegally manufactured opioids, Pittsburgh, Pennsylvania, October 2024-March 2025. MMWR. Morbidity and Mortality Weekly Report, 74(15), 269-271. https://doi.org/10.15585/mmwr.mm7415a3

Philadelphia Department of Public Health. (2025, June 10). Responding to overdose and withdrawal involving medetomidine (PDPH-HAN-00440U). https://hip.phila.gov/health-alerts/responding-to-overdose-and-withdrawal-involving-medetomidine/

Philadelphia Department of Public Health. (2026, June 22). Emerging practices for managing medetomidine withdrawal in the outpatient setting (PDPH-HAN-00463U). https://hip.phila.gov/document/6386/PDPH-HAN-MWD-06.22.2026.pdf/

Pennsylvania General Assembly. (2026). House Bill 2529 and Senate Bill 866, 2025-2026 Regular Session. https://www.palegis.us/legislation/bills/2025/hb2529 ; https://www.palegis.us/legislation/bills/2025/sb866

Ohio Board of Pharmacy. (2026, August 26). Controlled Substances Advisory Committee agenda. https://pharmacy.ohio.gov/documents/lawsrules/csadvisorycommittee/controlled%20substances%20advisory%20committee%20-%20agenda%20-%208.26.2026.pdf

South Dakota Legislature. (2026). House Bill 1169 (enrolled). https://sdlegislature.gov/Session/Bill/27007/305236

Virginia General Assembly. (2026). Acts of Assembly, Chapter 447 (H 1103). https://lis.blob.core.windows.net/files/1218007.HTML