Furanyl fentanyl has been detected in blood samples from 8 fatalities, initially believed to be heroin or other opioid-related drug overdoses. The fatalities occurred in the US between October 2015 and March 2016. However, other drugs were detected in all cases (e.g. U47700:5, 4-ANPP:5, Quinine:5, morphine:1, tramadol:1, butyrfentanyl:1, delta-9-THC:1) (Moher et al, 2016). In 281 unintentional overdose fatalities, during January–February 2017, approximately 90% of all decedents tested positive for fentanyl, 48% for acryl fentanyl, 31% for furanyl fentanyl, and 8% for carfentanil in 24 Ohio counties in the US (Daniulaityte et al. 2017). Furanyl fentanyl (0.34 ng/mL) was detected, along with carfentanil (1.3 ng/mL) and fentanyl (6 ng/mL) in the postmortem blood of a 34-year old male in Florida, US. Morphine and hydromorphone were also detected (Swanson et al, 2017).
The US Drug Enforcement Agency (DEA) has reported that it is currently aware of 128 confirmed fatalities associated with furanyl fentanyl. These fatalities occurred in Illinois (36), Maryland (41), New Jersey (1), North Carolina (49), and Ohio (1) beginning in 2015. However, these fatalities may overlap with those described above. The DEA has suggested that the extent of abuse and mortality associated with this synthetic opioid is likely to be underestimated since it is not included in regular drug screening tests (US DEA 2016). A cluster of 43 overdose events caused by crack cocaine contaminated with furanylfentanyl occurred in British Columbia, Canada (July 2016). 22 patients became unconscious after smoking the cocaine, 40 patients were taken to the emergency department, three of which were put into the intensive care unit (1 died). Furanylfentanyl and cocaine were detected in samples collected by the hospital and local police. Reports from first responders, the community, and emergency department staff members indicated that patients required high doses of injectable naloxone, in some cases up to 3.0 mg (usual dose = 0.4 mg) (Klar et al, 2016). Furanyl fentanyl was also analytically confirmed in 2 fatalities in Sweden, however, other drugs were detected in both cases (e.g. 4-methoxybutyrfentanyl:1). The serum concentrations were 4.4 and 148 ng/mL and in urine 9.2 and 85 ng/mmol creatinine, respectively. Typical clinical features were decreased consciousness, respiratory depression, and miosis. (Helander et al, 2015).