An Emerging Synthetic Opioid in the Drug Supply: A Case of Opioid Overdose with Biological Confirmation of Cychlorphine.
Journal of medical toxicology · 2026-07-21 · Case report
Abstract
INTRODUCTION: Cychlorphine (also referred to as N-propionitrile chlorphine) is a non-fentanyl synthetic opioid that has been linked to the illicit drug supply and fatal overdoses in the United States since 2024. CASE REPORT: A female in her 20s presented to the emergency department (ED) following ingestion of what the patient reported was alprazolam. Unresponsiveness and respiratory depression prompted 6 mg of intranasal naloxone administration by emergency medical services prior to arrival to the ED. Comprehensive toxicological testing of serum revealed the presence of cychlorphine. Additional substances found were bromazolam, carboxy-THC, acetaminophen, caffeine, citalopram, cotinine, naloxone, naproxen, nicotine, and trazodone and its metabolite. DISCUSSION: This rare case of clinical signs of opioid overdose with cychlorphine detected is the first to provide direct evidence linking a non-fatal overdose to cychlorphine exposure. A naloxone responsive opioid toxidrome is described with an opiate and fentanyl negative initial urine drug screen. Advanced analytical techniques were required to identify the presence of cychlorphine.