Addictions and Recovery

44. An increasing number of very potent drugs, especially medetomidine, are entering the illicit opioids market.

On September 4, 2024, the Journal of the American Medical Association (JAMA) published an article by Palamar and Krotulski describing the increased incidence of drug overdoses due to medetomidine, a racemic mixture of dexmedetomidine and levomedetomidine which is commonly used to produce sedation and analgesia in veterinary medicine.

Dexmedetomidine alone is a Food and Drug Administration–approved drug for human administration and is commonly used in hospital settings. When used properly in a hospital setting, the sedative effects of medetomidine reportedly last for 2 to 3 hours. However, recreational use has been associated with longer periods of sedation and recovery times sometimes requiring hospital admission, in large part due to higher dosages consumed and coexposure with other central nervous system depressants.

Medetomidine is sometimes referred to as “rhino tranq” or simply “mede” by its users.

Medetomidine chemical structure

The following is map of states in which medetomidine has been detected in drug products and in biospecimens of people who use drugs, January 2021-July 2024.

While naloxone is effective at reversing the overdose effects of heroin and fentanyl, it is not effective at reversing the overdose effects of the following drugs:

Medetomidine has been around for quite a while

In 1987, Scheinin et. al. report their findings of injecting 25, 50 and 100 ug (micrograms) of medetomidine to eight healthy male volunteers in a double-blind, placebo-controlled study. One hundred micrograms is, indeed, a very small quantity, considering that the average grain of sand has a mass of 50 micrograms.

Sand from the Gobi desert

They also noted dose-dependent reductions of systolic and diastolic blood pressure, heart rate and saliva secretion, and sedation or impairment of vigilance, both by subjective and objective assessments, with the highest dose actually inducing sleep in five of the subjects.

Its principal use is in veterinary medicine

In 2003, Melissa Sinclair wrote a review article on the applications and physiological effects of medetomidine in small animal practice, i.e. dogs and cats. Among healthy patients, medetomidine has a good drug profile, and is able to produce reliable sedation and anxiolysis.

Among sick, unstable, or cardiovascular compromised patients, there are significant negative cardiovascular effects, including:

  • bradycardia (slow pulse);
  • bradyarrhythmias;
  • a dramatic reduction in cardiac output by up to 50%; and
  • an increase in systemic vascular resistance, the last of which is defined as the resistance that must be overcome for blood to flow through the circulatory system. Under continued sedation, blood pressure returns to normal levels.

There are additional effects on other organ systems:

  • Respiratory effects
    • Reduction in respiratory rates
    • Increased arterial carbon dioxide tension
    • hypoxemia and cyanosis when medetomidine is used for premedication and anesthesia induced by propofol.
  • Muscular relaxation and analgesia, and muscle twitching.
  • Hypothermia
  • Endocrine
    • Medetomidine suppresses the stress response, thus it has the potential of increasing survival
    • Suppresses insulin release, thereby increasing serum glucose and glucagon release.
  • Excretory
    • Animals recovering from sedation from alpha2-agonists such as medetomidine typically have large volumes of urine to excrete. The diuretic effect may last up to 4 hours.

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Palamar, J.J.; Krotulski, A.J. (2024). Medetomidine Infiltrates the US Illicit Opioid Market. JAMA. Published online September 4, 2024. doi:10.1001/jama.2024.15992

Scheinin, M.; Kallio, A.; Koulu, M.; Viikari, J.; Scheinin. (1987). Sedative and cardiovascular effects of medetomidine, a novel selective a2-adrenoceptor agonist, in healthy volunteers. Br. J. clinical Pharmacology 24:443-451.

Sinclair, M. (2003). A review of the physiological effects of α2-agonists related to the clinical use of medetomidine in small animal practice. Can Vet J. 2003 Nov; 44(11): 885–897.