ToxIC NOSE Report #22 | Cychlorphine: An Emerging Opioid

The ToxIC NOSE (Novel Opioid and Stimulant Exposure)
Report #22 from ToxIC’s Rapid Response Program for Emerging Drugs

Cychlorphine: An Emerging Opioid

Rebecca Kusko, MD & Kim Aldy, DO, MS, MBA

Introduction

Cychlorphine (or N-propionitrile chlorphine) is a non- fentanyl synthetic opioid that emerged in late 2025 in the United States. It belongs to the orphines, a class of opioids that includes brorphine, which continue to have new analogs reported.1,2 As with other opioids, there is a significant risk of fatal respiratory depression in overdose.

Increasing amounts of cychlorphine have been identified in patient samples since late 2025 by the Center for Forensic Science Research and Education (CFSRE).2 Since then, it has been detected in the illicit drug supply in at least 10 states, with the greatest prevalence in Ohio, Texas, and Tennessee.4 Cychlorphine often co-occurs with other opioids, traditional stimulants, or novel benzodiazepines.2 Because of its recent emergence and illicit nature, reliable data are limited, however it is thought to be as potent or more potent than fentanyl.2,4 Due to cychlorphine’s novel structure, hospital urine drug screens for opiates and fentanyl will have a negative result. In addition, fentanyl or nitazene test strips will not flag cychlorphine, putting patients at additional risk.5

The following report presents a case of non-fatal opioid overdose with cychlorphine identified through the Toxicology Investigators Consortium (ToxIC) Fentalog Study, an ongoing multicenter prospective observational project that includes adult patients presenting to the emergency department (ED) with suspected opioid overdose.6 For all patients in the Fentalog Study, clinical data are collected, and residual blood specimens remaining after routine ED clinical testing are sent to the Center for Forensic Science Research and Education (CFSRE) for comprehensive toxicological analysis.