Cychlorphine Overdose Surge Across the United States

Emergency medical services in Austin, Texas, recorded 98 opioid-overdose calls in the most recent 30-day period, up from 73 calls a year earlier. Nine patients required more than two doses of Narcan, versus two such cases the previous year. Across the nation, the synthetic opioid cychlorphine—estimated up to ten times more potent than fentanyl—has been linked to a growing number of fatal overdoses and emergency calls.

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Cychlorphine (N-propionitrile chlorphine) belongs to the “orphine” class of lab-made opioids. First synthesized in a Belgian laboratory in the 1960s, the compound never received medical approval. Academic publications eventually made the synthesis recipe publicly accessible, enabling illicit production. The drug entered U.S. illicit markets in mid-2024, first detected in Florida, and has since spread to multiple states, Canada, and several European nations.

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• Detection reports: ONDCP logged 106 cychlorphine detections in 10 states during 2025, up from a single report in 2024.

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• National death toll: ONDCP’s April 2026 update linked at least 55 deaths to cychlorphine; CFSRE reported 140 deaths across almost 20 U.S. states and Canada.

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• State spikes:

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• Tennessee’s Knox County recorded 64 deaths between July and September 2025.

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• Louisiana confirmed two cychlorphine-related deaths since December 2025.

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• International spread: UNODC confirmed presence in 17 countries as of September 1 2026, documenting 78 post-mortem cases.

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• Law-enforcement warning: The DEA cautioned that cychlorphine is increasingly mixed with fentanyl and counterfeit pills, rendering standard fentanyl test strips ineffective.

Deadly synthetic opioid found in counterfeit pills

• Public-health guidance: LDH advises residents to administer a second dose of naloxone if the first does not restore breathing.

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• Surveillance advocacy: Mississippi state health officer Dan Edney told the Mississippi Free Press on September 23 that, although cychlorphine has not yet been detected in Mississippi, the state could be vulnerable and urged legislative support for proactive monitoring of drug shipments.

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• Local outreach: Knox County officials have partnered with treatment providers and law-enforcement agencies to disseminate alerts and track fatalities.

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• “Of those, nine patients required more than two doses of Narcan to reverse the overdose. One to two doses is what's common,” — Captain Christa Stedman

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• “As deadly as this drug is, it could have a significant impact on the rate of drug-related deaths. It is deadly in the smallest quantities,” — Chris Thomas

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Standard hospital opioid urine screens and at-home fentanyl test strips do not detect cychlorphine because its chemical structure differs from established opioids. Overdoses may be misclassified as fentanyl-negative, likely undercounting the true national burden.

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The need for multiple Narcan doses has strained EMS resources. In Austin, calls requiring more than two doses rose from roughly 2 % to over 9 % within a year, prompting EMS leadership to alert the public about heightened risk.

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• Cause attribution: Multi-substance overdoses often prevent definitive attribution to cychlorphine.

Deadly synthetic opioid found in counterfeit pills

• Human potency data: Laboratory studies suggest ten-fold potency over fentanyl, but no human clinical data exist, leaving real-world potency estimates uncertain.

Deadly synthetic opioid found in counterfeit pills

Federal and state agencies are expanding surveillance, issuing drug-threat notices, and encouraging wider naloxone distribution. Limited detection capabilities suggest cychlorphine-related harms may remain under-reported until broader toxicology testing becomes routine.

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