An accidental poisoning with mitragynine

•We present a case report of an accidental poisonings with mitragynine and 7-hydroxymitragynine.•Toxicological findings are discussed.•An UPLC–MS/MS method for the quantitative determination of mitragynine and 7-hydroxymitragynine.

An increasing number of drugs of abuse are sold word wide over the internet. Names like “legal highs”, “herbal highs” etc. give the impression that these are safe products, although the risk of fatal reactions might be substantial. Leaves from the plant Mitragyna speciosa, contain active compounds like mitragynine and 7-hydroxymitragynine. It has been reported that the potency of 7-hydroxymitragynine at the μ-opioid receptor is 30 times higher than that of mitragynine and 17 times higher than that of morphine. Case reports regarding poisoning with Kratom are reported, but the toxic or lethal ranges for the concentrations of the active substances have not been established, and concentrations of 7-hydroxymitragynine have not been reported previously.We present a case report where a middle aged man was found dead at home. The deceased had a history of drug abuse and mental illness for several years. At autopsy, there were no significant pathological findings. Post-mortem analysis of peripheral blood revealed: zopiclone 0.043 mg/L, citalopram 0.36 mg/L and lamotrigine 5.4 mg/L, i.e. concentrations regularly seen after therapeutic ingestion of these drugs. Additionally mitragynine 1.06 mg/L and 7-hydroxymitragynine 0.15 mg/L were detected in blood and both also in urine.The high concentrations of mitragynine and 7-hydroxymitragynine indicate that the cause of death is intoxication by these substances; and the circumstances point toward the manner of death being accidental. We recommend that both mitragynine and 7-hydroxymitragynine are analyzed for in cases with suspected Kratom intoxication.