Distribution of mirtazapine (Remeron) in thirteen postmortem cases

Mirtazapine is a new antidepressant agent that entered the United States market in April 1996. To date, the literature provides limited information about therapeutic blood concentrations and virtually no information about postmortem levels. The Los Angeles County Coroner's Toxicology Laboratory has encountered 13 cases where postmortem tissue distributions of mirtazapine were determined. The analysis of mirtazapine from postmortem specimens (2-mL sample size) consisted of an n-butylchloride basic extraction procedure with identification and quantitation on a gas chromatograph-nitrogen-phosphorus detector. Linearity was achieved from 0.025 mg/L to 3.0 mg/L with a limit of quantitation of 0.025 mg/L. Confirmation of mirtazapine was performed on a gas chromatograph-mass spectrometer by comparison with a pure analytical standard. The tissue distribution of mirtazapine are in the following concentration ranges: heart blood 0.03-0.57 mg/L (13 cases), femoral blood 0.04-0.24 mg/L (9 cases), vitreous 0.06-0.10 mg/L (3 cases), liver 0.32-2.1 mg/kg (12 cases), bile 0.40-6.6 mg/L (7 cases), urine 0.12-2.5 mg/L (11 cases), kidney 0.23 mg/kg (1 case), spleen 0.17 mg/kg (1 case), and gastric 0.001-2.7 mg total (9 cases). Mirtazapine was not implicated in the cause of death in any of the 13 cases studied. These cases are being presented to aid the forensic toxicologist in the evaluation of postmortem mirtazapine levels.