KNOXVILLE, Tenn.—Researchers and law enforcement nationwide continue to look into a new drug that more than likely hit the country in late 2024; surfaced in East Tennessee last summer; and has so far appeared in 41 deaths in Knox County and surrounding areas.
Another five deaths are in what the Knox County Regional Forensic Center refers to as the “early notification process,” meaning the drug has been detected in fatal overdoses but more studies are needed to definitively link it to the death.
The new drug is called N-Propionitrile Chlorphine, or cychlorphine for short. Little is known about the synthetic opioid at this point, but it is spreading quickly, and it is far stronger than fentanyl – possibly 10 times as strong. It has not been approved for human use. Like fentanyl, it’s mixed in with other street drugs, but it’s not detectable through most test kits, so it’s even more dangerous.
“What’s especially troubling is that cychlorphine may have been circulating far longer than we know,” said Chris Thomas, chief administrative officer and director of the Knox County Regional Forensic Center. “And I’ve said this before – we don’t know if it’s contained to a limited supply or one bad batch, or if it’s representative of a longer-term shift in the drug supply. That’s what is really concerning.”
For example, the Knox County RFC was one of the first to discover the drug here in Tennessee. That’s because the facility has the partnership resources needed for detection. Initially, officials thought it first appeared in November 2025. But as more deaths are studied and more research becomes clear, cychlorphine has now been linked to earlier deaths.
As it stands, the Knox County RFC says the drug was included in the toxicology in 41 deaths between July 2025 and February 2026. Those deaths were located in Anderson, Blount, Campbell, Claiborne, Grainger, Jefferson, Knox, McMinn, Roane, Sevier and Union counties.
“It has never been more dangerous to take street-level drugs than right now,” Thomas said.
In January, the Center for Forensic Science Research & Education (CFSRE) issued a public alert due to the spread of cychlorphine. It’s now been detected in nine other states, although officials think it’s in many more states as well.
In early March, Thomas took part in the 8th annual East Tennessee Opioid Conference held inside The Venue at Lenoir City. There, he told a crowd of hundreds that: “I hear people say Knox County has a big drug problem but that’s not exactly true – we have the best surveillance.”
He noted that the KCRFC and state agencies test for cychlorphine while other states either don’t or can’t, although that’s expected to change.
“Technology will help diagnose trends,” Thomas said at the time. “A decade ago, drug testing strips were not advanced enough to detect fentanyl and now they are.”
Officials believe cychlorphine originated in China in 2024 and quickly moved to Europe before hitting the United States in late 2024 where it possibly first appeared in Florida, according to reports.
The CFSRE noted that synthetic opioids are chemically manufactured drugs, often having unknown potency and adverse effects. Synthetic opioids can be sold alone but are frequently mixed with more traditional opioids, such as fentanyl or heroin, and other substances in unregulated drug markets.
About the Knox County Regional Forensic Center
The RFC, which operates 24/7, 365 days each year performs autopsies for 23 counties and is the official medical examiner for Knox, Anderson and Blount counties.
The RFC’s mission is to provide accurate, timely, compassionate and professional death investigative services for the residents of Knox County and the counties it serves; identify and develop an understanding of sudden, unexpected and unnatural deaths, and educate the public about those deaths; assist law enforcement agencies in their investigations; offer consultation to medical professionals and attorneys; render unbiased opinions and testimony in court; and extend research support for local and national medical, legal, academic and law enforcement organizations.
