Mitragynine concentrations in two fatalities

•Two postmortem cases are compared with regard to the role of mitragynine in the fatalities.•A significant difference could be seen in the absolute concentrations of mitragynine detected for the two cases.•A significant difference could be seen in the relative concentrations of mitragynine to its diastereomers between the two cases.•Mitragynine was not the direct cause of death in either of the two cases, despite an extremely high blood mitragynine concentration in one of the two.

Two cases of fatalities are reported of which the recreational use of Mitragyna speciosa (“kratom”) could be confirmed. One of these cases presents with one of the highest postmortem mitragynine concentrations published to date. Our results show that even extremely high mitragynine blood concentrations following the consumption of kratom do not necessarily have to be the direct cause of death in such fatalities as a result of an acute overdose. The two cases are compared with regard to the differences in mitragynine concentrations detected and the role of mitragynine in the death of the subjects. Irrespective of the big differences in mitragynine concentrations in the postmortem blood samples, mitragynine was not the primary cause of death in either of the two cases reported here. Additionally, by rough estimation, a significant difference in ratio of mitragynine to its diastereomers in the blood and urine samples between the two cases could be seen.