Postmortem femoral blood concentrations of risperidone

Postmortem femoral blood concentrations of the antipsychotic drug risperidone and the active metabolite 9-hydroxyrisperidone were determined by an achiral LC-MS/MS method in 38 cases. The cause of death was classified as unrelated to risperidone in 30 cases, in which the sum of the concentration of the drug and metabolite ranged from below the limit of quantification to 0.058 mg/kg (median 0.0098 mg/kg). This concentration range, which largely corresponds to published in vivo plasmalevels under therapy, may serve as a reference for judgment of postmortem cases involving risperidone. In one case, risperidone was judged to be a contributing factor to death, and the sum of concentrations was 0.29 mg/kg. This concentration is of the same order of magnitude as observed for plasma levels in clinical intoxication cases. For the remaining seven cases, the cause of death was unclear. The measurements observed here do not suggest that risperidone is subject to major postmortem redistribution.