A powerful synthetic opioid called cychlorphine, which is up to 10 times stronger than fentanyl, has been linked to dozens of overdose deaths across the United States since late 2025. Health officials have issued urgent warnings as the drug spreads rapidly and proves difficult to detect with standard testing.

According to an April 2026 drug threat notice from the White House Office of National Drug Control Policy (ONDCP), cychlorphine has been found in every region of the country, with significant clusters in Tennessee, Ohio, and Texas. The ONDCP reported at least 55 deaths nationwide between July 2025 and February 2026, with Tennessee alone accounting for 41 of those fatalities. The drug was identified in 106 drug samples from 10 states in 2025, a sharp rise from just one sample in 2024.

Cychlorphine is classified as a novel synthetic opioid, known as an orphine, and is not a form of fentanyl. Like other opioids, it can slow or stop breathing, leading to death, especially in high doses. The drug has been detected both alone and mixed with other substances, including fentanyl, methamphetamine, cocaine, and sedatives. It also appears in counterfeit pills that resemble prescription medication, increasing the risk of accidental exposure, especially among teens and young adults.

One major challenge is that cychlorphine cannot be detected by routine hospital urine screens or common fentanyl test strips. This "dangerous diagnostic blind spot," as Anita Gupta, adjunct assistant professor of anesthesiology and pain medicine at Johns Hopkins School of Medicine, told Helio, makes it hard for clinicians to identify and respond to overdoses in time.

Health officials urge anyone who may encounter an opioid overdose to administer naloxone (Narcan) immediately and call 911. Although naloxone remains effective against cychlorphine, its high potency often requires multiple doses, rapid airway management, and extended monitoring to prevent fatal outcomes.

States most affected by the surge in cychlorphine include Tennessee, Ohio, and Texas, but health warnings have been issued in at least 13 states, including California, Illinois, Louisiana, Missouri, New Hampshire, North Carolina, Pennsylvania, Arizona, Alabama, Colorado, Hawaii, Kentucky, Michigan, Oklahoma, South Carolina, and Washington.

The ONDCP advises first responders and the public to be prepared with extra naloxone and stresses the importance of calling emergency services immediately in the event of a suspected overdose. Experts also recommend ongoing education, increased naloxone distribution, and advanced laboratory testing to help public health officials track and respond to this evolving threat.