Science1 publisher2 min readPublished
Cychlorphine, a synthetic opioid routine screens miss, has reached all four US Census regions
Cychlorphine, a synthetic opioid first seen in the US in 2024, is linked to at least 55 deaths and has reached all four Census regions. Standard test strips and hospital urine screens cannot detect it, so the usual quick checks for opioids do not work on it.
The Scientist · Science desk
What happened
- Cychlorphine, also called N-propionitrile chlorphine, was first detected in the US in 2024 by the Center for Forensic Science Research and Education.
- Current pharmacological tests at that center suggest it may be up to 10 times as potent as fentanyl.
- At least 55 deaths across 2025 and 2026 were linked to the drug, the Office of National Drug Control Policy said in April 2026.
- It has entered the illicit supply in all four US Census regions, according to the agency, most heavily in Ohio, Texas and Tennessee.
- By the end of 2025 it had been identified more than 100 times in drug samples from 10 states, against one report in 2024.
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Why it matters
- constraint For a person checking a pill or a clinician working out what caused an overdose, a negative result on a standard test strip or routine hospital urine screen cannot rule cychlorphine out.
- exposure Because it has turned up alongside cocaine and methamphetamine, people who use only stimulants can take in a potent opioid without ever seeking one.
- precedent Cychlorphine belongs to an emerging subclass of novel synthetic opioids, so test panels and warnings written around a single compound name are likely to need revising as related compounds appear.
Potency is measured per unit of weight. The CFSRE figure is a ceiling from current pharmacological tests, framed as what cychlorphine may reach [2]. It describes how little of the compound is needed to act. That matters because of where opioids act. They attach to receptors that block pain signals, and those same receptors help control breathing. High doses can slow breathing to levels that kill [11]. A more potent compound reaches that point at a smaller quantity.
The spread figures are counts of positives. One report in 2024 became more than 100 identifications across 10 states by the end of 2025 [5], at least a hundredfold rise in a year [1]. A count like that moves with two things: how much of a drug is circulating, and how many labs are testing for it. A jump from one to 100 fits real spread. It also fits a lab network learning to look for a new compound, and the tallies as published do not separate the two. The death count covers 2025 and 2026 [3], a longer window than the sample count.
Awareness campaigns on counterfeit pills have moved one measure. Song for Charlie, a national group that educates people about fake prescription pills, told WMTV about teen awareness. The share of teenagers who know fentanyl turns up in counterfeit pills went from 27 percent in 2021 to 65 percent today, according to the group [8]. That is a 38-point gain [2], and the question was about fentanyl. The group's figures also show that 33 percent of teenagers see a pill from someone close to them as dangerous, against almost 90 percent for a pill from a stranger [9]. The gap is about 57 points [3]. According to Discover, cychlorphine can be included in counterfeit pills made to imitate prescription medication [12].
Discover's report does not say whether naloxone reverses a cychlorphine overdose, or at what dose. Whether current overdose response plans hold up against this compound depends on that answer.
What to watch
- Any CFSRE or ONDCP data on whether naloxone reverses cychlorphine overdoses, and at what dose.
- Whether test-strip makers or hospital labs add cychlorphine to routine screens; wider testing would also change how many cases get counted.
- An updated ONDCP death count and state list, showing whether prevalence stays concentrated in Ohio, Texas and Tennessee.