Knox County’s regional forensic lab is sounding the alarm after preliminary toxicology linked 16 overdose deaths to a new synthetic opioid called N‑propionitrile chlorphine, better known on the street as cychlorphine. The deadly cluster, first flagged in late November 2025, has now turned up in multiple East Tennessee counties. Medical examiners say the drug may be even more potent than fentanyl and warn that standard overdose reversal could take repeated doses of naloxone to work.
Forensic findings and local cases
The Knox County Regional Forensic Center reports that preliminary tests found cychlorphine in the blood of people who died in the region, bringing the total number of linked fatalities to 16, according to WBIR. The center says it first picked up the substance after a late November 2025 death in Roane County and has since shared its findings with partner labs while it waits for full confirmation, as reported by WATE. Officials note that toxicology confirmation can be slow, since labs have to match samples against constantly evolving reference materials for new synthetic drugs.
Why responders are alarmed
Dr. Darinka Mileusnic‑Polchan, the center’s chief medical examiner, told reporters the new compound “is more powerful than fentanyl,” and warned that naloxone may not fully block its effects, meaning some cases could require several doses to pull someone back, according to WBIR. That possibility has first responders and harm‑reduction groups bracing for longer, more complicated resuscitations and stocking up on extra naloxone.
Origin and broader surveillance
The Center for Forensic Science Research and Education has been tracking N‑propionitrile chlorphine since mid‑2024 and says early lab data suggest it is related to brorphine‑style analogues and may be roughly ten times as potent as fentanyl, according to a public alert from CFSRE. The group notes tentative identifications in toxicology cases across several U.S. states and Canada, while international monitoring organizations trace this family of compounds back to China in 2024, according to the UNODC.
Other states reporting the drug
Beyond Tennessee, state forensic labs are starting to spot the compound as well. Ohio’s Bureau of Criminal Investigation reported an October seizure that contained N‑propionitrile chlorphine and said responders had to use multiple naloxone doses to revive a person, according to the Ohio Attorney General's Office. That case came on the heels of earlier detections reported by federal and commercial labs in 2024 and 2025.
Harm‑reduction steps and resources
Harm‑reduction advocates are sticking to familiar advice, only with a new sense of urgency. They urge people to carry naloxone, avoid using drugs alone, and call 911 immediately if an overdose is suspected. Syringe‑residue testing programs are also keeping a close eye on local drug supplies to catch dangerous changes early. The University of Kentucky’s Harm Reduction Hub operates a syringe‑residue testing program, and state tools such as FindNaloxoneNow list locations where people can access naloxone and other support services.
What’s next
Knox County officials say toxicology work is still underway and that families may need to wait several weeks for final confirmation in individual cases while investigators try to determine whether the deaths stem from a single contaminated batch or a wider, sustained trend. For now, authorities are stressing vigilance, easy access to naloxone, and rapid emergency response as the community’s best defenses.
