Postmortem drug concentration intervals for the non-intoxicated state - A review

Area of Science:

• Forensic Toxicology
• Clinical Chemistry
• Pharmacology

Background:

• Accurate interpretation of postmortem drug levels is crucial for identifying poisoning.
• Therapeutic drug levels are typically established using serum concentrations, often referencing The International Association of Forensic Toxicologists (TIAFT) list.
• Postmortem redistribution can significantly alter drug concentrations in blood compared to serum.

Purpose of the Study:

• To compare published postmortem blood drug reference intervals with therapeutic serum levels from the TIAFT list.
• To assess the agreement and identify discrepancies between these two sources of drug concentration data.
• To emphasize the impact of postmortem redistribution on drug level interpretation.

Main Methods:

• Collected and analyzed published postmortem-derived blood drug reference concentration intervals.
• Compared these intervals with therapeutic serum drug levels from the TIAFT list for 57 compounds.
• Evaluated the ratio between the upper limits of these intervals to quantify discrepancies.

Main Results:

• Wide discrepancies were observed between serum-based and postmortem blood-based drug reference intervals.
• The ratio of upper limits ranged from 0.13 to 11.3 (median 1.5), with about a third exceeding three.
• Highly water-soluble drugs with low redistribution potential showed lower ratios, while antidepressants and antipsychotics exhibited higher ratios.

Conclusions:

• Existing TIAFT serum-based therapeutic drug levels show significant discrepancies with postmortem blood reference intervals.
• Postmortem redistribution necessitates a greater focus on postmortem-derived drug reference intervals.
• Development of a reliable database of postmortem blood drug reference intervals is essential for the forensic community.