Case studies of postmortem quetiapine: therapeutic or toxic concentrations?

The focus of this study was to determine if the analysis of a variety of postmortem biological specimens would aid in the toxicological interpretation of quetiapine in the cause and manner of death determinations. Postmortem quetiapine concentrations were examined in 21 medical examiner cases using liquid-liquid extraction and high-performance liquid chromatography analysis. Specimens analyzed were peripheral blood, central blood, liver, vitreous humor, and gastric contents, when available. Findings from this study suggest that therapeutic postmortem quetiapine concentrations may be less than 1 mg/L in both peripheral and central blood, less than 0.5 mg/L in vitreous, and less than 5 mg/kg in liver. Quetiapine concentrations indicative of toxicity were estimated at greater than 1 mg/L in peripheral and central blood, greater than 0.5 mg/L in vitreous, and greater than 5 mg/kg in the liver. Liver concentrations appeared to be particularly helpful in determining the potential for toxicity when compared with blood concentrations. Cases in which quetiapine was determined to play a significant role in the death indicated postmortem liver concentrations greater than 5 mg/kg. Cases in which quetiapine concentrations were considered incidental or noncontributory in the death had liver concentrations 2 mg/kg or less.