Description
Medetomidine is an α2-adrenergic agonist used as a veterinary anaesthetic. In recent years, medetomidine has emerged as an adulterant in illicit drugs, especially opioids. Around 100 times more potent than xylazine, medetomidine produces intense sedative effects.
Desirable Effects
- Relaxation
- Sedation
- Anti-anxiety effects
Undesirable Effects
- Unconsciousness
- Low heart rate
- Rapid and severe withdrawal symptoms including delirium
What does it look like?
In its pure solid form, medetomidine HCl is a white crystalline powder or solid. For medical infusions, dexmedetomidine comes as a clear solution in infusion bags (400 µg/100 mL) or concentrated ampoules and vials (various sizes equivalent to 10 mg/100 mL).
On the unregulated drugs market, medetomidine is usually found in missold heroin powder, opioid or benzodiazepine tablets of varying colours and forms. In these samples, you cannot see medetomidine by eye.
Method of Use
Injection: Dexmedetomidine is administered by IV infusion to human patients in intensive care. Medetomidine is given to animals by injection (intramuscular, intravenous, or subcutaneous).
Generally, human consumption of medetomidine is incidental and would follow the route of administration of the adulterated drug of intent.
Pharmacology
Medetomidine is a potent, selective α2-adrenergic receptor agonist, around 100x stronger than xylazine. By activating the α2-adrenergic receptor, medetomidine disrupts nerve signals in the part of the nervous system involved in the fight-or-flight response. This produces a strong sedative effect, including slowing down heart rate.
Unlike xylazine, medetomidine also acts as an imidazoline receptor agonist. This additional activity is thought to lead to stronger adverse effects such as bradycardia (slow heart rate) than are produced by xylazine, and contribute to medetomidine withdrawal syndrome. Withdrawals come on rapidly, setting in by 6–24 h after the last dose. Most commonly, withdrawal symptoms can include nausea, tachycardia (racing heart), anxiety, delirium and hypertension (high blood pressure). It is unclear whether medetomidine causes skin wounds similar to xylazine.
Medetomidine acts as a potent invertebrate octopamine receptor agonist and non-lethal barnacle repellent. Activation of octopamine receptors causes barnacles to start swimming rapidly, deterring them from sticking to the side of boats coated with medetomidine.
Medetomidine is metabolised in the liver by hydroxylation. The more potent medetomidine isomer that is approved for human use, dexmedetomidine, has an oral bioavailability of only 16% due to extensive first pass metabolism.
Due to its nervous system depressant effects, medetomidine in combination with other depressants such as opioids can increase the risk of overdose. In an opioid overdose involving medetomidine, naloxone administration can reverse the opioid effects but the individual may remain heavily sedated.
History
Medetomidine was developed by Orion Pharma in the 1980s for use as a veterinary sedative in Europe, receiving FDA approval in the US in 1996 for use in dogs. In 1999, dexmedetomidine (the more active part of medetomidine) received FDA approval for use as a short term sedative and pain-relieving agent for patients in intensive care under the brand names Dexdor and Precedex.
In 2000, biophysicists Dahlström and colleagues found that medetomidine and the related drug clonidine stopped barnacles from settling on surfaces. In the mid-2010s, Swedish biotech company I-Tech brought medetomidine to the market under the brand name Selektope® as a more environmentally friendly agent used in commercial boat coatings.
On the unregulated drugs market, medetomidine has become more common in the US since 2024, especially in combination with opioids. Between November 2025 and May 2026, 15 benzodiazepine samples tested by WEDINOS contained medetomidine, with one containing medetomidine alongside the benzo bromazolam.
Law
On 12 January 2026, the government accepted the ACMD’s recommendation to place medetomidine in Class C of the Misuse of Drugs Act 1971 and Schedule 4 Part I of the Misuse of Drugs Regulations 2001. However, at the time of writing the government has yet to implement this into law.
At the time of writing
- Psychoactive Substances Act 2016
Possible offences
- Possession With Intent To Supply
- Maximum sentence – 7 years/fine/both
- Supply (including being concerned in supply, conspiracy to supply, aggravated supply and offer to supply)
- Maximum sentence – 7 years/fine/both
- Import/Export
- Maximum sentence – 7 years/fine/both
In practice maximum sentences are rarely used, for more detailed and accurate information go to our sentencing page.
