Oxycodone-related fatalities in the west of Scotland

Abstract

The intent of this study was to review fatalities involving oxycodone in the west of Scotland using a liquid chromatography-electrospray ionization-tandem mass spectrometry method developed for the determination of oxycodone and N- and O-demethylated metabolites in unhydrolyzed postmortem specimens. Ten oxycodone positive postmortem cases were detected, and nine were drug-related fatalities. Five cases were attributed solely to oxycodone intoxication and four to polydrug intoxication. Although there was overlap between blood oxycodone levels in deaths attributed to oxycodone only and those due to polydrug intoxication, lower oxycodone levels (< 1 mg/L) were associated with polydrug intoxication when compared with cases due to oxycodone alone (> 1 mg/L). The role of the parent drug in oxycodone fatalities has been fully studied, but the role of oxycodone metabolites (noroxycodone and oxymorphone) was investigated in this report for the first time. Oxycodone was more commonly detected in blood, urine, and vitreous humor followed by noroxycodone. The ratio between oxycodone and its N-demethylated metabolite was evaluated and found to be useful in determining whether death occurred shortly after drug administration or if there was a significant delay. High parent/metabolite ratios were correlated with short survival times after ingestion. The median ratio of oxycodone/noroxycodone was 2.4 and ranged from 0.7 to 49. Oxycodone prescriptions have risen sharply in Scotland in recent years, and the identification of 10 oxycodone-related deaths in the past 18 months highlights the importance of including this drug in routine laboratory screening and confirmation procedures.