Between 2010 and 2016, the percentage of deaths attributed to heroin and synthetic opioid overdose rose from 16% to 57% of all drug overdose deaths. Opioid-related deaths accounted for about 2/3 of total drug overdose deaths. The second-most common class of agents associated with drug overdose fatalities were benzodiazepines, followed by cocaine.
Synthetic opioids generally include fentanyl (and its relatives carfentanil, acetylfentanyl, etc.), methadone, and tramadol, although methadone was not included in this category for this study. The majority of synthetic opioid overdose deaths therefore implicate fentanyl-related drugs, which can be 50 to 10,000 times more potent than morphine.