A cluster of fentanyl-related deaths among drug addicts in Sweden.

During a 16-month period, nine fatalities occurred among white male drug-addicts, where fentanyl was detected at postmortem toxicological analysis. The street samples associated with these cases confirmed the presence of fentanyl as an additive in low-concentration amphetamine powders with caffeine, phenazone and sugar as cutting agents. In seven of the cases, an acute intoxication by fentanyl was considered to be the immediate cause of death, and in one case, it was likely, but no analysis of fentanyl was performed in blood, and in another case the death was suicide by hanging. This appears to be the first report of a cluster of fentanyl-related deaths outside the United States, and the occurrence of fentanyl in combination with amphetamine has not previously been reported. In addition, in all cases, femoral blood was collected, and samples were handled and analysed according to standardized, quality-controlled procedures. The previous history, circumstances surrounding the death, autopsy findings, histology and toxicology examination of each case are presented. The gas chromatographic-mass spectrometric method for fentanyl is also described. Fentanyl concentrations ranged from 0.5 to 17 ng g-1 blood, and from 5 to 160 ng ml-1 urine. Other drugs found were amphetamine (8 cases), ethanol (5 cases) and benzodiazepines (5 cases). Morphine was found in only one case. The average age of men was 33.9 years (range 22-44); six were found in their own of friend's apartment, two inside buildings (stairways) and one was found outdoors. We conclude that fentanyl is a dangerous substance that should be considered in drug-addict deaths even outside the United States, particularly when the remaining toxicology is unremarkable, and the cause of death cannot be ascertained