Mitragynine 'Kratom' related fatality: a case report with postmortem concentrations

A 24-year-old man whose medical history was significant for alcohol abuse and depression was found unresponsive in bed. He had several prior suicide attempts with 'pills' and had also been hospitalized for an accidental overdose on a previous occasion. Autopsy findings were unremarkable apart from pulmonary edema and congestion, and urinary retention. Postmortem peripheral blood initially screened positive for mitragynine 'Kratom' (by routine alkaline drug screen by gas chromatography-mass spectrometry, GC-MS), which was subsequently confirmed by a specific GC-MS selective ion mode analysis following solid-phase extraction. Concentrations were determined in the peripheral blood (0.23 mg/L), central blood (0.19 mg/L), liver (0.43 mg/kg), vitreous (<0.05 mg/L), urine (0.37 mg/L) and was not detected in the gastric. Therapeutic concentrations of venlafaxine, diphenhydramine and mirtazapine were also detected together with a negligible ethanol of 0.02% (w/v). The results are discussed in relation to previous cases of toxicity, and the lack of potential for mitragynine postmortem redistribution.