Researchers and law enforcement are warning about a newly emerging synthetic opioid showing up in East Tennessee overdose deaths: N‑Propionitrile Chlorphine (also called “cychlorphine”).

The Knox County Regional Forensic Center says cychlorphine was detected in toxicology in 41 deaths from July 2025–February 2026 across Knox and 10 surrounding counties, with 5 additional cases still in an early notification stage as experts work to confirm the drug’s role.

What makes this especially alarming: officials say it may be far stronger than fentanyl (possibly 10x), it’s not approved for human use, it’s often mixed into other street drugs, and it’s not detectable with most test kits, making it even more dangerous.

“It has never been more dangerous to take street-level drugs than right now,” said Chris Thomas, chief administrative officer and director of the Knox County Regional Forensic Center.

If you or someone you know is struggling with addiction, help is available: 988 (Suicide & Crisis Lifeline) and SAMHSA 1‑800‑662‑HELP (4357).