“Rhino Tranq” Emerging in Washington’s Illegal Drug Supply

WHATCOM COUNTY, Wash. — Local health officials are warning that a powerful new sedative could soon enter the Whatcom County drug supply after researchers detected it elsewhere in Washington.

Officials at Whatcom County Public Health say the substance, medetomidine, has not yet been confirmed locally. However, recent testing shows it is already circulating in other parts of the state. A study from the University of Washington identified medetomidine in Washington drug samples. Public health leaders say the drug increases overdose risk and complicates emergency response.

“Even if medetomidine is not here yet, the illegal drug supply remains extremely dangerous,” said Dr. Meg Lelonek, Whatcom County Co-Health Officer. “Illegal drugs lack quality control and often contain harmful fillers.”

A Dangerous New Additive

Medetomidine is a veterinary sedative that doctors do not approve for human use. People sometimes call it “rhino tranq,” “mede,” or “dex.” It is far stronger than xylazine and can cause deep sedation, slow heart rate, and low blood pressure. The drug often appears mixed with fentanyl, which increases overdose risk and makes treatment more difficult.

Medetomidine does not respond to naloxone, also known as Narcan. However, officials still urge people to use Narcan during suspected overdoses because fentanyl is usually present.

“If someone uses a mix of fentanyl and medetomidine, Narcan may restore breathing, but the person may not wake up right away,” health officials warn.

Regular use can also lead to severe withdrawal. Symptoms may include high blood pressure, anxiety, nausea, vomiting, and fluctuating alertness. Some cases require emergency care.

Regional Risk and Drug Trends

Drug trends often move north along the Interstate 5 corridor. Healthcare systems like PeaceHealth have seen waves of overdose cases when unusually potent batches reach the region. State data shows medetomidine has appeared alongside fentanyl in tested samples. Officials believe suppliers may add it to extend or intensify opioid effects.

Federal Advisory Adds Context

Earlier this month, the Centers for Disease Control and Prevention, working with the White House Office of National Drug Control Policy, issued a national advisory on medetomidine. Federal officials reported rising detections across the country, along with cases of severe withdrawal. Most samples containing medetomidine also contained fentanyl. Testing suggests the drug comes from illegal labs rather than diverted medical or veterinary supplies.

Harm Reduction Guidance

Public health officials urge people to take steps that reduce risk:

• Never use drugs alone  Carry naloxone (Narcan)
• Test substances when possible
• Call 911 if someone stops breathing or becomes unresponsive.

People who want help can find support through WhatcomHope.org.

Editor’s Note: Avoiding illegal drug use remains the only way to eliminate overdose risk. PNW Daily maintains that harm reduction guidance may reduce harm, but it does not replace prevention as a core public health responsibility. Carrying naloxone is a safety measure, not an endorsement. It can save lives in both overdose and accidental exposure situations.

A Continuing Shift in the Drug Supply

The emergence of medetomidine reflects a broader shift toward stronger and less predictable drug mixtures. Health officials say communities should remain alert as the substance spreads.

Sources: CDC Health Advisory HAN-00527  ·  UW Alcohol and Drug Abuse Institute — Washington Drug Checking