Public health and safety partners across the United States are issuing warnings about cychlorphine, a potent synthetic opioid identified in the illicit drug supply. This drug has been linked to at least 55 deaths nationally between 2025 and 2026, with a high prevalence in Ohio, Texas, and Tennessee. Cychlorphine, which may be up to 10 times more potent than fentanyl, poses a significant risk as overdoses may require multiple doses of naloxone to reverse its effects.

The emergence of such powerful and often hidden substances like cychlorphine complicates an already severe drug crisis, increasing the unpredictability of the illicit drug supply for users and first responders. People may unknowingly consume these highly potent drugs, significantly raising the risk of fatal overdose.

What the records show

Cychlorphine, also known as N-propionitrile chlorphine, belongs to a class of novel synthetic opioids called "orphines". It is structurally distinct from fentanyl, nitazenes, or morphinan derivatives, representing its own class of compounds. The drug has been found both alone and mixed with other substances, including fentanyl, methamphetamine, cocaine, and in counterfeit pills designed to look like prescription medications.

The Office of National Drug Control Policy (ONDCP) reported 106 drug-supply detections across 10 states in 2025, with finds in all four U.S. Census regions. In response to its growing threat, the Drug Enforcement Administration (DEA) temporarily placed cychlorphine in Schedule I in August 2026, using its emergency scheduling authority. Tennessee health officials specifically reported more than 30 fatal overdoses associated with cychlorphine from October 2025 through March 2026.

Before the rise of cychlorphine, nitazenes, another class of highly potent synthetic opioids, gained traction in the illicit drug market starting in 2019. These opioids were first synthesized in the 1950s but were never approved for medical use. Nitazenes are frequently mixed with other illicit drugs and sold in counterfeit pills, and some estimates suggest they can be 20 to 40 times stronger than fentanyl. Like cychlorphine, nitazene overdoses can be reversed by naloxone, but often require multiple doses due to their high potency. A February 2025 survey indicated low public awareness of nitazenes, with 80% of respondents unaware of their existence despite their growing presence. Following China's generic scheduling of nitazene analogs in July 2025, forensic surveillance programs observed a decline in nitazene detections and a sharp increase in the detection of 'orphine' analogs, including cychlorphine.

Adding to the complexity of the illicit drug supply, medetomidine, a veterinary sedative, has also emerged as an adulterant, particularly in the fentanyl supply. This substance, which can be up to 200 times as potent as xylazine, causes heightened sedation and profound bradycardia.

What the subject has said publicly

The DEA issued an advisory in May 2026, specifically naming cychlorphine, alongside nitazenes, as potent synthetic opioids increasingly found mixed into the nation's fentanyl supply and counterfeit pills.

What we could not confirm

The specific regions beyond Ohio, Texas, and Tennessee most affected by cychlorphine deaths could not be confirmed. The full extent of law enforcement actions beyond the DEA's scheduling could not be confirmed. The long-term trends of cychlorphine's spread following its Schedule I placement could not be confirmed.