CDC reports medetomidine overdoses in humans via adulterated street drugs 

Medetomidine was detected alongside fentanyl in the blood samples of twelve people treated for drug overdoses in Chicago, and it has been suspected in an additional twenty-six overdose cases in which patients presented with bradycardia that did not respond completely to reversal with naloxone.  

Medetomidine in veterinary medicine and beyond 

Medetomidine is an alpha2-adrenoceptor agonist used for anesthesia and analgesia in animals. Lauren Forsythe, PharmD, MBA, DICVP, a veterinary pharmacist and CEO of Foresight Pharma Solutions, LLC, explained that medetomidine is a racemic mixture of levomedetomidine and dexmedetomidine, the latter of which is the active enantiomer.  

Medetomidine and dexmedetomidine tend to have similar effects when given intravenously, she said, but medetomidine tends to produce a faster and more profound sedation when given intramuscularly. “Medetomidine was available before dexmedetomidine,” she added. “My experience is that often medetomidine use occurs with clinicians that were using it prior to dexmedetomidine and have continued to reach for it first.”  

According to CDC, medetomidine was first identified as an adulterant in illegally manufactured opioids in North America in 2022. The 2024 overdoses in Chicago, however, represent the first reported cluster of cases. “Medetomidine and xylazine are in the same drug class,” she said, referring to cases of xylazine also being reported as adulterants in illicit drug use, “so as we’ve locked down xylazine, medetomidine seems to be surfacing as the alternative of choice.” Forsythe explained that it is not yet known whether medetomidine is being diverted from veterinary supply chains or being produced illegally by drug traffickers. 

What can be done 

To help combat the addition of medetomidine to the “ever-changing and expanding” list of potential illicit drug adulterants, CDC is making efforts to educate healthcare providers on the signs of medetomidine exposure in humans, particularly since medetomidine is not typically included in standard urine drug screening, and to alert potential drug users that their drugs could be adulterated with medetomidine. 

Unlike in veterinary medicine, the reversal drug atipamezole is not approved for use in humans and therefore cannot be used for treatment of these overdoses in humans. This was the case with the xylazine illicit drug adulteration as well, Forsythe said. Atipazamole would have been an effective reversal agent, but it was not an option for treatment in humans.  

On the veterinary side of things, Forsythe highlighted some important action steps that hopefully most veterinary practices are already taking. While she stops short of recommending that veterinarians keep medetomidine (and dexmedetomidine, since this drug may also be at risk for diversion and abuse) locked up and logged as if it were a controlled substance, she does recommend keeping all drugs secured so that only those who are authorized to access them can.  

“Medetomidine (and any other prescription drugs) shouldn’t be located in a place that clients can access,” she said. Another important step to take is to keep close track of the practice’s drug inventory. “In my opinion, these concerns bump medetomidine (and dexmedetomidine) up higher on the priority drugs to check inventory of than some other non-controlled drugs.” 

Drug manufacturers also have a responsibility to track the raw ingredients they use to ensure they are from approved sources and verify that the drugs they produce are only being sold to licensed veterinarians, Forsythe said. 

At the state and federal levels, whether medetomidine will be considered for scheduling as a controlled drug will depend on whether additional cases of human exposure and overdose are reported, she added. “Given that xylazine is still not decided at the federal level, I don’t expect to see medetomidine becoming controlled federally anytime soon.” 

Further reading: 

 CDC Mortality and Morbidity Report, overdoses involving medetomidine mixed with opioids, Chicago, May 2024

Photo credit: MarioGuti/iStock via Getty Images

 Disclaimer: Trends™ content is meant to inform, educate, and inspire by providing an array of diverse viewpoints. Any content published should not be viewed as an official stance, position, or endorsement by the American Animal Hospital Association (AAHA) or its Board of Directors.