Suicide with cisatracurium and thiopental: forensic and analytical aspects

The suicide of a 43-year-old male by intravenous injection of cisatracurium, a non-depolarizing neuromuscular blocking agent, and thiopental, an ultra-short-acting barbiturate, is presented. Systematic toxicological screening by gas chromatography-mass spectrometry (GC-MS), liquid chromatography (LC)-diode-array detection, and LC-MS-MS confirmed the presence of thiopental. A large peak in the GC-MS chromatogram was matched by the Pfleger-Maurer library as corlumine, but neither atracurium neither its metabolite, laudanosine, were detected. To confirm the absence or the presence of laudanosine in the blood sample, an ultra-performance liquid chromatography-MS-MS method for cisatracurium and laudanosine quantification was developed. The calibration range was 2.5-500 ng/mL for laudanosine and 10-500 ng/mL for cisatracurium. The biases were lower than 12.3%. Intraday and interday precisions, expressed as coefficient of variation, were lower than 13.3%. This method allowed to confirm the presence of laudanosine and measurement of laudanosine in all samples. The femoral blood concentration was therapeutic (0.46 μg/mL). This case report documents a possible analytical pitfall and describes a simple and fast method for cisatracurium determination. Moreover, the purpose of this case report was to document the postmortem redistribution of cisatracurium and laudanosine, which could help make it possible to interpret tissue or cardiac blood concentrations in forensic cases where femoral blood is not available.