A new synthetic opioid linked to at least one overdose death in Oklahoma is raising concerns among health and law enforcement officials in the state.
Cychlorphine is a lab-made opioid that has recently emerged in the U.S. drug supply. It is not well-studied, but early reports indicate it is powerful and dangerous. It's part of the third phase of the opioid epidemic, in which synthetic drugs, like fentanyl, are driving overdose deaths.
The drug has been linked to overdose deaths in more than two dozen states, according to a news release from the Oklahoma Bureau of Narcotics. Last week, cychlorphine was involved in the overdose death of an 18-year-old from Yukon, the agency reports.
The agency warns that synthetic opioids are often pressed into counterfeit pills that can look convincing or legitimate, increasing the risk of accidental exposure and overdose.
"People don't know what they are buying," OBN Director Donnie Anderson said in the release.
Dr. Rachel Wirginis is an addiction medicine specialist at the OSU Addiction Recovery Clinic in Tulsa, where she works with patients with opioid use disorder. She said new types of opioids aren't necessarily surprising, but they are concerning.
"It's this arms race for more potent opioids," she said. "We'll probably see other families of opioids coming to the market too, as regulators catch up with these orphines, or drugs like cychlorphine."
She said illegal drug manufacturers are racing against regulators trying to stop the flow of illicit drugs. In 2025, President Donald Trump signed the controversial HALT Fentanyl Act, which, among other provisions, placed a class of compounds chemically related to the powerful opioid fentanyl in Schedule I of the Controlled Substances Act, making it easier to prosecute traffickers.
Wirginis said potent drugs are easier to transport because smaller, concentrated amounts can be more easily smuggled. But a more potent supply of drugs can endanger users.
Cychlorphine may be significantly more potent than fentanyl and, in some cases, more difficult to reverse with standard overdose treatments, like the fast-acting opioid antagonist naloxone.
"One spray of Narcan, or naloxone, is probably not enough," she said. "It might take multiple doses."
She also warns that some people may metabolize naloxone more quickly than cychlorphine, and could experience the effects of drug toxicity again after some time has passed.
Wirginis said there is limited research about how cychlorphine affects humans. It has been around since the 1960s, but it never came to market as a usable drug because of its overdose risks.
According to the latest provisional data from the Centers for Disease Control and Prevention, deaths from drug overdoses declined in Oklahoma last year to nearly half of those from the previous year. It's part of a national trend that health experts attribute to increased access to treatment, reduced stigma for seeking help and harm reduction efforts.
Wirginis said treatment for opioid use disorder is still the best practice against new types of opioids. She said new variants bring on new challenges, like not being able to be identified with fentanyl test strips, but there are still ways for people to get support.
Still, it's a difficult landscape for those navigating the changing supply — treatment providers and people who use drugs alike.
"We treat addiction as this chronic brain disease, and it's something that we manage over time," Wirginis said. "And so it's frustrating that folks that might be managing this disease as the drug supply evolves."
The Oklahoma Bureau of Narcotics reports it plans to collaborate with local leaders to add cychlorphine to the state's list of banned substances.
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