First Fatal Overdose Confirmed in Los Angeles
Los Angeles health authorities confirmed the first fatal overdose linked to cychlorphine, a synthetic opioid 10 times more potent than fentanyl, in February 2026. The drug, classified as a Schedule I substance by the DEA in August 2026, has been detected in 19 states and is being mixed into illicit drugs without users’ knowledge, officials said.
Los Angeles County’s health department reiterated its advice: “Never use drugs alone, not to mix drugs, and to carry naloxone.”
Potency Traps Users, Standard Tests Miss Cychlorphine
Cychlorphine’s extreme potency, which can cause death in small doses, has raised alarms among public health officials. The drug, which acts on μ-opioid receptors, may not be detectable by standard fentanyl test strips and may be missed by routine opioid screens, according to the White House Office of National Drug Control Policy (ONDCP). “A negative test cannot establish that a drug is safe,” the ONDCP warned in a September 2026 notice.
Health officials in Tennessee’s Knox County Regional Forensic Center noted that naloxone does not completely block the drug’s effects and multiple doses may be needed to prevent an overdose.
San Francisco Overdose Marks Spread, 55 Deaths Nationally
San Francisco health officials linked a fatal overdose to cychlorphine in April 2026, marking its first confirmed presence in the city. Between 2025 and early 2026, 55 deaths nationwide were tied to the drug, with Tennessee’s Knox County Regional Forensic Center reporting 63 fatalities between July 2025 and September 2026. The DEA identified 135 cychlorphine exhibits in laboratories since 2024, compared to more than 13,000 fentanyl exhibits tested between July 2025 and September 2026.
Cychlorphine has been confirmed in 225 law-enforcement encounters across 19 U.S. jurisdictions as of early 2026, according to a federal notice.
Health Officials Urge Naloxone, Caution Against Mixing
Health officials urge residents to avoid using drugs alone, refrain from mixing substances, and carry naloxone, a medication that can reverse opioid overdoses. While naloxone can counteract cychlorphine’s effects, multiple doses may be required, as noted by the Knox County Regional Forensic Center. “Naloxone doesn’t work on an opioid; it works on the receptors of the opioids by blocking them,” said Dr. Selick, a public health expert.
Counterfeit Pills Mimic Xanax, OxyContin, DEA Warns
Cychlorphine has been found in counterfeit pills resembling Xanax, OxyContin, and other medications. The drug is also mixed with fentanyl, methamphetamine, and cocaine, increasing the risk of accidental overdose.
The pills included substances represented as Xanax, oxycodone, and other drugs. The San Francisco Police Department said the medical examiner determined that a teenager died from a combination of drugs that included cychlorphine.
Synthetic Opioid Cycle: Fentanyl to Nitazenes to Cychlorphine
After fentanyl crackdowns, nitazenes rose in the illicit market, with seven variants scheduled as Schedule I drugs by the DEA.
Newly emergent opioids and other drugs constantly enter the illegal market, creating a “drug whack-a-mole” effect. Cychlorphine, which has no approved medical use, is part of this cycle, with reports of its presence in 10 countries and availability through international online drug markets.
Next Steps: DEA Monitors, Health Departments Sound Alarms
Health officials urge residents to never use drugs alone, not to mix drugs, and to carry naloxone. As cychlorphine’s presence grows, the emphasis remains on education, detection, and emergency preparedness. “A negative drug screen is no permission slip,” the White House warned, stressing that standard tests may miss the drug.
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