Hamilton County health officials are warning residents about cychlorphine, a synthetic opioid estimated to be up to 10 times more potent than fentanyl, after the drug was detected in local samples. The warning applies to all Hamilton County communities, including Sharonville, Springdale, Evendale and Woodlawn.

A Hamilton County Public Health spokesperson told WLWT, which first reported the warning Monday, Sept. 28, that in the limited samples where cychlorphine has turned up, it was found mixed with fentanyl. The spokesperson said any pill not obtained from a licensed pharmacy should be considered potentially deadly, because counterfeit pills can contain cychlorphine or other powerful substances without the user's knowledge.

Cychlorphine belongs to a new class of synthetic opioids called orphines. According to the federal Office of National Drug Control Policy (ONDCP), cychlorphine is not detected by drug test strips or in routine hospital opioid urine screens. That means someone testing a substance for fentanyl could get a negative result and still face a lethal dose.

Dr. Mike Kalfas, an addiction specialist with St. Elizabeth Healthcare, called cychlorphine "the newest monster to come on the scene" in the WLWT report.

Newtown Police Chief Tom Synan, who works with the Hamilton County Addiction Response Coalition (HC ARC), said the coalition first identified cychlorphine through drug testing about a year ago. The substance was first detected in Southwest Ohio after a seizure and test of illicit drugs in August 2025, according to an earlier WLWT report from February. In one case Synan cited, 20 different substances were found in a single drug sample seized and tested in Hamilton County.

Because of cychlorphine's potency, a single dose of naloxone, commonly sold as Narcan, may not be enough to reverse an overdose. The ONDCP urges bystanders to be prepared with extra doses.

The ONDCP issued a threat notice about cychlorphine in April, linking it to 55 deaths nationwide, USA Today reported. The Drug Enforcement Administration (DEA) announced in July that it would temporarily place cychlorphine in Schedule I, and the order took effect Aug. 27. Ohio is among the states with the highest prevalence, along with Tennessee and Texas, according to the ONDCP.

The county's overall overdose death toll has been declining. HC ARC's 2025 annual report, released in March, showed overdose deaths dropped for the fourth consecutive year. Cychlorphine threatens to complicate that progress.

The drug has also been found in counterfeit pills pressed to look like legitimate prescriptions such as oxycodone or hydromorphone. The Hamilton County Public Health spokesperson said cychlorphine has not been detected on college campuses in Greater Cincinnati, but local officials are discussing prevention efforts aimed at young people who could encounter it unknowingly.

Hamilton County Public Health provides free naloxone, fentanyl test strips - which can still detect fentanyl but not cychlorphine - and overdose prevention supplies by mail. Residents can call 513-316-7725 to order supplies or connect with resources.