Free oxycodone concentrations in 67 postmortem cases from the Hennepin County medical examiner's office

Heart blood free oxycodone concentrations in oxycodone-related and mixed drug overdose deaths were compared with those found incidentally at autopsy in medical examiner cases. Between 2000 and 2005, 67 oxycodone-positive postmortem cases were identified. Thirty of 67 cases (44.8%) were determined to be drug overdoses. Oxycodone alone was responsible for 7 of the 30 (23.3%) overdose deaths. Mean (median) oxycodone concentrations were 1.060 mg/L (0.824 mg/L) with a range of 0.270-3.390 mg/L. Three cases were accidents, three were suicides, and one was undetermined. The remaining 23 were mixed drug overdoses. Mean (median) oxycodone concentrations in these cases were 0.820 mg/L (0.470 mg/L) with a range of 0.014-3.800 mg/L. Sixteen mixed drug overdoses were accidental, and seven were suicidal. Where oxycodone was an incidental finding, 24 were natural, 6 accident, 4 suicide, 1 homicide, and 2 undetermined. The mean (median) concentrations in the incidental finding group were 0.330 mg/L (0.150 mg/L) with a range of 0.017-1.300 mg/L. In conclusion, the findings substantiate the considerable overlap that exists with blood oxycodone concentrations in cases where oxycodone alone was determined to be the cause of death compared with mixed drug overdoses and incidental findings. Free oxycodone concentrations in postmortem cases must be interpreted in the context of the deceased's past medical history and autopsy findings.