Health risks associated with smoking versus injecting fentanyl among people who use drugs in California

Routes of Drug Use Among Drug Overdose Deaths — United States, 2020–2022

“…Increases in the number and percentage of deaths with evidence of smoking, and the corresponding decrease in those with evidence of injection, might be partially driven by 1) the transition from injecting heroin to smoking IMFs ( 3 , 4 ), 2) increases in deaths co-involving IMFs and stimulants that might be smoked †††† ( 1 ), and 3) increases in the use of counterfeit pills, which frequently contain IMFs and are often smoked ( 7 ). Motivations for transitioning from injection to smoking include fewer adverse health effects (e.g., fewer abscesses), reduced cost and stigma, sense of more control over drug quantity consumed per use (e.g., smoking small amounts during a period versus a single injection bolus), and a perception of reduced overdose risk among persons who use drugs ( 3 , 5 , 8 ). These motivations might also signify lower barriers for initiating drug use by smoking, or for transitioning from ingestion to smoking; compared with ingestion, smoking can intensify drug effects and increase overdose risk ( 9 ).…”

“…These motivations might also signify lower barriers for initiating drug use by smoking, or for transitioning from ingestion to smoking; compared with ingestion, smoking can intensify drug effects and increase overdose risk ( 9 ). Despite some risk reduction associated with smoking compared with injection (e.g., fewer bloodborne infections), smoking carries substantial overdose risk because of rapid drug absorption ( 5 , 9 ).…”

“…Routes of drug use have implications for overdose risk, infectious disease transmission, and harm reduction services ( 5 ). Although unsafe injection drug use practices might be most risky in terms of infectious disease transmission, other routes, particularly smoking, still carry substantial overdose risk ( 9 ).…”

“…More recent data suggest transitions from injecting heroin to smoking IMFs; however, limited data exist on recent changes in routes of drug use for all drugs, and for IMFs beyond the western United States † ( 3 , 4 ). Routes of drug use have implications for overdose risk, infectious disease transmission, other comorbidities, and harm reduction services ( 5 ).…”

Innovation and adaptation: The rise of a fentanyl smoking culture in San Francisco

“…Smoking heroin is considered more protective of overdose, compared to injection [ 37 ], due to potentially slower intake and lower blood concentrations, i.e., decreased bolus effect. Recent data showing a self-reported reduction in non-fatal overdoses among people who smoke fentanyl compared to people who inject fentanyl suggest this may also be true to some extent for the more potent opioid, fentanyl [ 38 ]. Much of the smoking consumption we witnessed involved smaller doses with high frequency, compared with those seen in our previous research with heroin/fentanyl via injection [ 25 , 39 , 40 ].…”