The SF fentanyl supply is getting laced with new varieties of the drug, like the potentially five times more powerful drug fluorofentanyl, and the veterinary tranquilizer with the street name “tranq.”

There is plenty of media attention and public discourse about San Francisco fentanyl overdose deaths, street-level fentanyl dealing, and the increased law enforcement response to these crises. One aspect that does not get as much attention is the work of medical professionals behind the scenes who are testing samples from overdose victims to figure out what exactly was in the drugs they used, and how the chemical makeup of the drug supply is changing over time.

The SF Office of the Medical Examiner just released a lengthy and highly technical report on a retest of 2022 overdose samples. The Chronicle sums up that report, which found that two new forms of fentanyl are creeping into the supply, one of them a little-known analogue called  fluorofentanyl, and the other the well-publicized variation “tranq,”  a veterinary tranquilizer whose technical name is xylazine.

The analogue fluorofentanyl was originally used in research going back to the 1960s, but was declared an illegal narcotic in 1986, and the Chronicle says it “can range from half to five times as powerful as prescribed fentanyl.” Tranq is a veterinary tranquilizer that’s not even meant for human consumption, and can create festing wounds that often require an amputation. And any new form of fentanyl gets experts worried.

“Even if it replaces (fentanyl) in a minor way, that’s a problem,” UCSF addiction medicine specialist Dr. Daniel Ciccarone tells the Chronicle. “If it’s stronger, a lot stronger, that will affect the overdose risk.”

The retesting determined that 45 SF users had fluorofentanyl in their system at the time of their death in 2022, while 15 others had tranq in their system. (This is out of 647 opioid deaths overall.) In 2023, they’ve found tranq in the systems of nine overdose deaths, though they cannot yet estimate how many had fluorofentanyl in their systems.

Thus far in 2023, SF has seen 406 overdose deaths through the end of June. Of those, 324 were fentanyl overdoses.

The Department of Health will use this data to determine allotments of treatment beds, which medications they will use for addiction treatment, strategies to steer people into recovery, and strategies for Narcan distribution.

Related: Death Involving New Street Drug 'Tranq' Confirmed In San Jose [SFist]

Image: @SFPDTenderloin via Twitter