A new drug, the umpteenth, is spreading through the United States and has already reached some countries in Europe. It is called medetomidine although on the street they call it 'rhino tranq', 'mede' or 'dex'. It is another case of an existing substance being given a new use by the drug market. Because medetomidine is a drug, a veterinary sedative commonly used to anesthetize large animals (hence the name they give it on the street).
The use of medetomidine in the US has skyrocketed 950% in just one year and has already been detected in 46 states and US territories. The Centers for Disease Control and Prevention (CDC) reported that the number of drug samples containing medetomidine increased from 247 in 2023 to 2,616 in 2024, subsequently recording a further increase of 215%, reaching 8,233 samples in 2025.
Already in 2025, the United States Drug Enforcement Administration (DEA) warned in its annual report (with data from 2024) that it had begun to detect an anesthetic normally used in dogs and cats, which was more powerful than fentanyl. It was the first alarm about medetomidine.
Medetomidine, a sedative for animals
It is a drug used in veterinary medicine for sedation, muscle relaxation and pain relief, often during surgeries. Medetomidine works by slowing the release of adrenaline in the brain and body (technically it is what is called an alpha-2 adrenergic agonist).
Before medetomidine there was xylazine. It is another sedative, analgesic and muscle relaxant and is also used in veterinary medicine as an animal tranquilizer. The problem is that the sedative effect of medetomidine is similar but more powerful. The CDC says its effect is longer, and the New Jersey Department of Health estimates that medetomidine is 100 to 300 times more potent than xylazine.
'Rhino tranq' has been found as a brown powder and in white tablets sold as diazepam (Valium). As is done with xylazine, in the US medetomidine is mixed with strong opioids, such as heroin or fentanyl. It has also been detected alongside stimulant drugs such as cocaine, and was found in items sold such as counterfeit codeine tablets and even THC vaporizers.
The 'rhino tranq' is, as its name suggests, extremely potent. Medetomidine suppresses brain signals in the central nervous system, resulting in deep sedation. For all these reasons they call it "zombie drug." There have been cases of teenagers jumping out of windows or getting into heavy traffic on a highway. Its consumption can cause tachycardia, sharp spikes in blood pressure, restlessness, disorientation, confusion and intense vomiting.
Its overdose is more serious than other drugs, causing states of stupor with loss of consciousness, life-threatening withdrawal symptoms and severe skin damage. As Detox New Jersey claims, medetomidine can cause severe withdrawal that has sent patients to intensive care. "Its abrupt discontinuation after repeated exposure has been associated with a severe, potentially fatal withdrawal syndrome," according to a medical study published in the Annals of Internal Medicine.
The 'rhino tranq' has arrived in Europe
The new drug has crossed the Atlantic; at least to the United Kingdom, according to the Daily Record newspaper. Last July, a drugs report by the Scottish public health body warned that medetomidine had been detected in a fifth of heroin samples analyzed in Scotland between March and June.
Rhino tranq was first detected in Scotland at the end of 2025. Since then, its presence has been identified in toxicological analyzes carried out on people with addictions who were treated in the emergency departments of Scottish hospitals. In England, the Greater Manchester Drug Early Warning System has issued a warning warning users that the combination of ketamine and medetomidine "is likely to result in extreme and prolonged sedation, which may be fatal."
Some reports highlight that 'rhino tranq' is being used as a drug to facilitate sexual assault. "Some individuals use it as a drug to facilitate sexual assault. It is so powerful that it causes a total loss of consciousness and memory; victims wake up without knowing what has happened," says Steve Pope, an addiction specialist in Lancashire.
