A new synthetic drug believed to be 10 times more potent than fentanyl has been linked to dozens of deaths in Tennessee, with a growing number of fatalities reported in states across the U.S.
The drug, N-Propionitrile chlorphine was first detected in toxicology from postmortems in mid-2024 by the Center for Forensic Science Research and Education, in Horsham, Pennsylvania, and since then its use appears to have exploded.
The drug belongs to an emergent subclass of synthetic opioids known as “orphines,” which first appeared on the recreational drug market in 2020, according to forensic experts. The drug is often manufactured to resemble legitimate prescription pills or other substances, making it difficult for individuals to know what they are taking.
Adding to the risk is the fact that N-Propionitrile chlorphine is not detectable by fentanyl testing strips.
Authorities in Tennessee have linked the drug to 41 deaths in 11 counties so far in 2026. The Oklahoma State Bureau of Narcotics reported at least one death related to N-Propionitrile chlorphine in March, while a public safety warning was issued by Kentucky in February.
The drug has appeared in seven other states: California, Nevada, Texas, Louisiana, Illinois, New York and Pennsylvania. It has also been linked to deaths in three Canadian provinces.
“It has never been more dangerous to take street-level drugs than right now,” Chris Thomas, chief administrative officer and director in Knox County Regional Forensic Center, Tennessee, told WATE. “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.”
N-Propionitrile chlorphine has been found in toxicology reports alongside other drugs such as fentanyl and methamphetamine, the center states. Fentanyl is believed to be 50 to 100 times more potent than heroin.
“Cychlorphine represents a dangerous shift in the opioid crisis,” said Dr. Rachel Wirginis, an addiction medicine and family medicine physician at the OSU Addiction Recovery Clinic in Tulsa, Oklahoma. “We are seeing increasingly powerful synthetic opioids that require rapid recognition and aggressive intervention to prevent fatal outcomes.”
The Independent has contacted the U.S. Drug Enforcement Agency for further information on N-Propionitrile chlorphine.
The exact origin of the drug is unknown, though some experts believe it is being produced at scale. “Most of these are coming from either South Asia, China, places where there’s a lot of chemical supply companies,” Timothy Wiegand, president-elect of the American Society of Addiction Medicine, told The Hill.
“It isn’t coming just like somebody in their bathroom, making it like methamphetamine, from a couple of products or in the U.S. It’s coming from international, multilevel drug distribution networks, some of the cartels or other isolated networks.”
