New synthetic opioid linked to 19 Tennessee deaths exposes limits in detection and legal clarity

Tennessee’s overdose surveillance system is not designed to detect newly engineered synthetic opioids quickly. The emergence of N-propionitrile chlorphine, commonly referred to as cychlorphine, is demonstrating that reality in real time. 

The compound has been identified in 19 overdose deaths in East Tennessee, with 12 confirmed and seven pending laboratory confirmation, according to the Knox County Regional Forensic Center. The molecule itself is new. The structural issue it exposes is not. 

Most routine postmortem toxicology panels are built to detect commonly encountered substances. If a newly engineered compound is not included in the panel, it does not appear in official results unless additional testing is ordered. That is not a failure of individual laboratories, it is how toxicology systems are constructed. 

Chief Administrative Officer Chris Thomas, who also serves as director of the Knox County Regional Forensic Center said laboratory data indicate cychlorphine is approximately 10 times more potent than fentanyl. In at least one confirmed fatal case, it was the only drug identified, measured at approximately 0.5 nanograms in femoral blood. 

A nanogram is one-billionth of a gram. 

The Tennessee Bureau of Investigation crime laboratory reported 11 seized drug submissions testing positive for cychlorphine in 2025 and nine additional submissions in the first 30 days of 2026. All were submitted by law enforcement agencies in East Tennessee. Seizure data does not establish cause of death. It does establish circulation. 

The public question is direct: Can this drug only be detected after someone fatally overdoses? 

No.

Cychlorphine can be detected in seized materials. It can be identified through expanded toxicology panels when laboratories test for it. What is not uniform is routine screening. Many standard blood toxicology panels do not include the compound because it has only recently emerged in the United States. Without expanded testing, it will not appear in mortality data. 

Testing practices vary across Tennessee. In Knox County and several surrounding counties, served by Knox County Regional Forensic Center, femoral blood samples are routinely sent for broader commercial toxicology analysis. When cychlorphine is detected samples are forwarded to a specialized laboratory for confirmation. In other jurisdictions, laboratories may test only for standard panels unless there is a specific reason to suspect an unusual substance. Targeted testing can be requested. It is not automatic. 

Detection is possible statewide. Detection is not automatic statewide. That is a distinction that matters in a state of 95 counties and uneven forensic capacity. 

Thomas confirmed that a Knox County death on July 31 involved cychlorphine but was not initially recognized as part of a pattern. At the time, it appeared isolated. Only after additional deaths occurred did investigators identify what is now considered a developing cluster. National surveillance systems reflect the same structural lag. 

The Centers for Disease Control and Prevention confirmed that N-propionitrile chlorphine was added to the State Unintentional Drug Overdose Reporting System, known as SUDORS, in early 2025 after a state-level staff member requested its inclusion following at least one detected death. CDC officials acknowledged that mortality data are not designed for early detection of emerging substances because overdose investigations, toxicology testing, and death certifications require time. By the time a compound appears in national mortality reporting, it has often already been flagged through product surveillance or laboratory identification programs. 

In other words, mortality data confirms patterns. They rarely discover them. 

For Tennessee policymakers, this is not solely an enforcement question. It is a visibility question. I contacted the offices of Rep. Jason Zachary, Knoxville, and Rep. Lowell Russell, Vonore, regarding the compound’s legal status under Tennessee law, with Russell asking for more information.  

Internationally, the reporting shows Tennessee is not alone. Cychlorphine has been identified in drug-checking programs in Toronto, confirmed in a peer-reviewed forensic research in France, and scheduled under Germany’s New Psychoactive Substances Act. Authorities in London have linked cychlorphine to fatal overdose investigations. 

Whether cychlorphine proves short-lived or sustained is unknown. What is clear is that synthetic opioids can circulate quietly until laboratory protocols adapt to detect them. 

The difference between detection and non-detection is not geography. It is infrastructure.