A synthetic opioid four to 10 times more potent than fentanyl has been detected in Ohio. The drug, cychlorphine (also spelled cyclorphine), cannot be detected by standard fentanyl test strips or routine hospital urine screens.

An overdose may require multiple doses of naloxone to reverse, according to a drug threat notice the White House Office of National Drug Control Policy (ONDCP) issued on April 30. Ohio has the highest prevalence of the drug in the country, alongside Texas and Tennessee.

The Ohio Bureau of Criminal Investigation (BCI) received its first cychlorphine sample in July 2025 after an overdose in Butler County, which borders Hamilton County to the north, as WKRC first reported. Lab submissions have climbed since, with the largest surge from March to April 2026.

Jessica Toms, lab manager of BCI's Drug Chemistry Section, pointed to Ohio's highway network as a factor.

"There are a lot of trafficking routes and lanes that run through here, with 75 and 70 both being great routes in which to transport things," Toms told WKRC.

She said proximity to Canada and routes from Florida and the Southwest also play a role.

Toms said people fighting addiction and those experimenting with substances face the greatest risk because cychlorphine is often mixed with other illicit drugs. Users can be exposed without knowing it. She identified college students as particularly susceptible.

BCI says cychlorphine can remain in someone's system for two or more days, complicating overdose response. The DEA says the drug first appeared in the U.S. drug supply in 2024 and is increasingly showing up in counterfeit pills made to look like Xanax, Percocet and Adderall, Denver7 reported.

Nationally, cychlorphine has been linked to at least 55 deaths from 2025 to 2026, according to the ONDCP notice. Reports jumped from one in 2024 to 106 across 10 states in 2025. As of March 2026, at least 24 states had reported overdoses or deaths linked to the drug, according to MedPage Today, citing the National Institutes of Health.

How to get free naloxone

Hamilton County Public Health distributes naloxone at no cost to residents in Hamilton, Butler and Clermont counties. Free kits are available by mail.

The department also provides naloxone to fire departments, EMS and police departments. Fentanyl test strips are available by mail; residents can text "FTS" to 844-734-4081. While those strips will not detect cychlorphine, officials say they remain useful for identifying fentanyl in the drug supply.

Hamilton County Public Health offers in-person overdose recognition and response training and runs a "leave behind" program that provides naloxone, test strips, first aid supplies and a resource card at overdose scenes.

No Hamilton County-specific advisory on cychlorphine had been issued as of Sept. 28. BCI's lab continues testing samples and is also monitoring related strains, including spirochlorphine and spiromorphine.