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Drug more powerful than fentanyl found in San Francisco

The area around United Nations Plaza in San Francisco has become a hotbed of contention for city officials, as they struggle with its issues of drug-dealing, illegal vending, vagrancy and empty storefronts and offices. | Jason Henry for The Standard

A drug called fluoro fentanyl, which is believed to be up to five times more powerful than fentanyl in some cases, has infiltrated the supply of drugs in San Francisco, a report from the Office of the Chief Medical Examiner has confirmed.

The chief medical examiner’s office released a report on Tuesday that found 45 people had died in 2022 after ingesting fluoro fentanyl, which ranges in potency from half the strength to five times as powerful as generic fentanyl. 

The report suggests that novel drugs are migrating across the country from the East Coast, similar to the trajectory of fentanyl from 2013 to 2016. 

Fluoro fentanyl is considered a novel opioid, though it’s chemically similar to fentanyl.

The office reanalyzed the cases of 617 people who overdosed in 2022, finding that 15 people had ingested a dangerous new animal tranquilizer called xylazine, or Tranq, and 48 people ingested a novel synthetic opioid.

People using drugs on the city’s streets have told of a deadly new opioid’s presence for months, saying that it has a stronger high that makes it more difficult to recover from an overdose. 

The emergence of novel drugs has raised concerns among health experts in San Francisco.

Keith Humphreys, a Stanford professor who worked on drug policy for the Obama administration, said that fluoro fentanyl is made by black-market chemists and was never approved for medical use. He said he was alarmed to find out from The Standard that the drug was found in San Francisco.

“In some 30-odd years of working in medical schools and hospitals, I’ve never heard of people using this for medical procedures,” Humphreys said. “I don’t think they even use that in animals.”

Humphreys said the city should invest in wastewater testing to detect the presence of dangerous new drugs before they’re found by the medical examiner. 

“We’re finding out about these things when we have a bunch of dead bodies,” Humphreys said. 

The city has seen a surge in overdose deaths this year and is on pace to lose a historic number of lives to drugs. The city’s health department has engaged in a new messaging campaign urging drug users to seek treatment.

Xylazine, in particular, is known to mimic the symptoms of an overdose but is immune to overdose reversal medication because it’s not an opioid.  

Everyone who died after ingesting xylazine in San Francisco had also ingested fentanyl, according to the report. 

David Sjostedt can be reached at