Credit: Center for Forensic Science Research and Education (CFSRE)
The Center for Forensic Science Research and Education (CFSRE) has issued a public health alert regarding a novel psychoactive substance seen recently in illicit drug material that is similar to but even more potent than xylazine, the so-called “zombie drug.”
In July 2022, medetomidine (Domitor) was detected in several seized drug samples across the state of Maryland, as well as in drug paraphernalia and illicit drug seizures submitted to public health and law enforcement agencies. Since then, it has also been detected in overdoses in St. Louis and clandestine laboratory seizures in Ohio, Florida and Canada.
Medetomidine is a potent surgical anesthetic approved for veterinary use in large and small animals. Another form of the drug, its dextro-isomer dexmedetomidine (Dexdor, Precedex) is also utilized in human medicine. Clinically, it is used to induce sedation, analgesia, anxiolysis and muscle relaxation.
The compound belongs to the class of a2-adrenoceptor agonists, which includes xylazine, romifidine, and detomidine. However, veterinary studies have shown medetomidine to be a more potent, selective, and specific agonist in the peripheral and central nervous systems than xylazine.
Animal studies have shown both cardiovascular and respiratory adverse side effects, including:
- initial, short-lived hypertension followed by dose-dependent hypotension and bradycardia
- increased chance of arrythmias
- decreased respiratory rates and overall respiratory depression
- hypnotic or anesthetic effects (at high doses)
- spontaneous muscle contractions (at high doses)
- dose-dependent mydriasis (at high doses).
According to CFSRE’s public health alert, indicators of medetomidine toxicity also include sedation, analgesia, dry mouth and hypothermia.
Medetomidine has most frequently been observed in samples containing fentanyl and xylazine, though the drug has also been identified together with fentanyl analogs, heroin and cocaine. It is typically a minor component in these samples, but is of great toxicological concern.
Medetomidine does not respond to naloxone (Narcan). However, naloxone administration is recommended since medetomidine is almost always found in combination with opioids. Similar to warnings with xylazine, the co-positivity of medetomidine with cocaine, opioids or other illicit drugs may prolong the effects of these drugs, which can lead to adverse consequences.
The adverse symptoms of medetomidine over-exposure should be treated with supportive respiratory care and management of blood pressure.