UCSF Professor of Family and Community Medicine Dr. Daniel Ciccarone said the U.S. opioid epidemic has unfolded in "three waves."
"Wave one: pills. Wave two: heroin. Wave three: fentanyl," he said.
Dr. Phillip Coffin, Director of Substance Use Research at SFDPH, said that the increase is most likely due to supply and cost: More people are choosing fentanyl because it costs less than heroin, and the available fentanyl may be of a higher quality than available heroin.
"Fentanyl started entering San Francisco in 2015, and we managed to avoid significant increases in mortality really until this year," he said. "We all expected that this other shoe would drop. We're of course disappointed but not surprised to see the increase in mortality with the increased prevalence of fentanyl use in the city."
Coffin attributed part of the initial delay in fentanyl overdose deaths to what he described as San Francisco's "culture of overdose prevention" among people who use drugs. "They're the ones who are reversing overdoses. They're the ones who are saving each other's lives," he said.
There were 259 overdose deaths in San Francisco last year resulting from all street drugs, including opioids, cocaine and methamphetamine, a 17% increase over 2017, and the highest number recorded since 2006, when the department began tracking data through its current system.
Methamphetamine-related deaths also jumped significantly, from 99 in 2017 to 126 in 2018, the data show.
The city is employing several measures to combat opioid overdoses, including overdose education, treatment for opioid addiction, use of fentanyl test strips, and distribution of naloxone, a drug used to reverse opioid overdoses.
