San Francisco health authorities are raising urgent concerns after a powerful synthetic opioid was detected in the city for the first time, and is already being tied to a fatal overdose earlier this month.

Officials with the San Francisco Department of Public Health say the drug, known as cychlorphine, surfaced in a counterfeit pill, prompting alarm over its extreme potency and unpredictable presence in the illicit drug market.

“We believe it is more potent than fentanyl. It was found we believe in someone using a counterfeit pill,”  Daniel Tsai, director San Francisco Department of Public Health told ABC7.

Law enforcement officials say the substance was first identified just last year.

“The first time DEA saw it was in 2024 at one of our labs down in Florida,” Bob Beris, special agent in Charge of the DEA San Francisco Field Division told ABC. “I mean, a pill can show up in Chicago and, you know, 30 hours later, it can be in San Francisco, you know, using the I-80, the 99, I-5. These are major corridors.”

Authorities warn that cychlorphine is not confined to pills alone and can be hidden across multiple street drugs, making detection and avoidance especially difficult.

“It can be mixed into a pill. It can be sold as a powder. It can be mixed in with cocaine. It can be sold as cocaine. Again, just because we haven’t seen some of these examples yet doesn’t mean it’s not out there,” Beris said.

Public health experts are also sounding the alarm over testing limitations, saying current drug-checking tools may not catch the substance.

“Importantly, it’s not detected on the available fentanyl test strips that are out there. So it’s very important to really try to avoid counterfeit pills altogether,” Dr. Philip Coffin, director of the Center on Substance Use and Health at SFDPH told ABC.

Another major concern is its suspected resistance to overdose reversal drugs like Narcan, potentially requiring multiple doses to be effective.

Community organizations on the front lines say they are responding by expanding emergency resources.

“Code Tenderloin has doubled the amount of Narcan we pass out per night. And also informing the community, we work in promotional preventative rehabilitative care. 

And we have to inform the community and educate them,” Douglas Liu, executive director of Community Health Workers Code Tenderloin told ABC.

Health officials from both the DEA and SFDPH are urging the public to avoid counterfeit pills entirely, warning the illicit supply is becoming increasingly unpredictable and dangerous.

Meanwhile, the crisis is unfolding alongside other alarming developments in the drug supply nationwide.