San Francisco’s Department of Public Health released new overdose data for May 2026, showing that overdose deaths have declined compared with the same time last year. But health officials are now warning about a new synthetic opioid — more potent than fentanyl — that could increase the risk of fatal overdoses, especially among young people.
Dr. Christy Soren, the medical director of substance use services at the Department of Public Health, said two newly identified synthetic opioids have recently appeared in San Francisco for the first time.
“These synthetic opioids, N-Propionitrile Chlorphine, also known as cychlorphine, and N-Desethyl Isotonitazene, have been implicated in a small number of overdose deaths across the nation," Soren said. "But this was the first time that we saw these substances present here in San Francisco."
According to health officials, these newer opioids are often mixed into counterfeit pills, making them difficult for users to identify.
“Counterfeit pills are advertised to look like and to be sold under the same name as prescription drugs," Soren continued. "So usually they may be Xanax, Adderall, oxycodone are common ones, and they're often pressed to look identical even though they may contain a variety of substances."
Officials say counterfeit pills are commonly marketed through social media and sold through unregulated channels. The new synthetic opioids can be up to 10 times stronger than fentanyl. In some cases, a single pill may be enough to cause a fatal overdose.
San Francisco recorded its first overdose death linked to these substances in April. In response, the Department of Public Health is urging people to only take medications prescribed by a licensed clinician.
While fentanyl remains the city’s biggest overdose challenge, health officials and community organizations continue working to expand prevention and treatment efforts.
Soren said overdose prevention tools remain effective and that public awareness remains critical.
“We want people to know how to recognize an overdose and to use naloxone, also known as Narcan, which can reverse an overdose and is available over the counter,” she said.
Previous research has suggested that these newer opioids may be more resistant to standard doses of Narcan. But Soren said the medication can still work, it may simply need to be administered multiple times.