Post-Mortem Redistribution (PMR)
Definition
The phenomenon where drug and poison concentrations shift between body compartments after death, generally moving out of solid organs back into the central blood through passive diffusion. Cardiac blood concentrations can rise several-fold post-mortem; femoral (peripheral) blood is less affected and is the preferred matrix for quantitation.
- Cardiac blood increase
- Drug levels can rise 2 to 10 times post-mortem
- Mechanism
- Passive diffusion from organs to blood as cell membranes lose integrity
- Preferred specimen
- Femoral (peripheral) blood, which is less affected
Common questions
Why does cardiac blood give false high drug levels after death?+
After death, cell membranes lose integrity, allowing drugs to diffuse passively out of organ tissues (heart, liver, lung) back into the central blood. Cardiac blood sits in direct contact with these high-concentration organs, so drug levels there can rise 2 to 10 times within hours. This is why toxicologists prefer femoral (peripheral) blood, which stays more stable.
Which drugs show the strongest post-mortem redistribution?+
Lipophilic drugs with high volume of distribution (Vd) show the greatest PMR. Examples include tricyclic antidepressants (TCAs), fentanyl, methadone, and digoxin. These drugs accumulate in fat and organ tissue during life, so they have more depot stores to redistribute into blood after death.
Does femoral blood really avoid post-mortem redistribution?+
Femoral blood is less affected by PMR because it sits in peripheral vessels away from the high-concentration organs. While some redistribution still occurs throughout the body, femoral levels remain closer to true ante-mortem concentrations than cardiac blood, making it the preferred sampling site for accurate drug quantitation.
Related terms
- Viscera
- The standard set of organs and fluids collected at a suspected poisoning autopsy in India: stomach with contents, a length of upper...
- Vitreous Humour
- The gel-filled interior of the eye, anatomically isolated from hepatic and gastric post-mortem redistribution sources. In forensic toxicology of hooch deaths, vitreous...
- 6-Monoacetylmorphine (6-MAM)
- A transient diagnostic metabolite of heroin (diacetylmorphine) formed by the rapid hydrolysis of one acetyl group. Half-life is 6 to 25 minutes...
- Benzoylecgonine (BE)
- The major hydrolysis metabolite of cocaine, formed by carboxylesterase action on the methyl ester of cocaine. Half-life is around 6 hours in...
- BNSS Forwarding Form
- The viscera-forwarding requisition that accompanies sealed bottles from the autopsy mortuary to the SFSL or CFSL. Successor to the CrPC-era Form 65...
- Chain of Custody
- The documented chronological record of who collected, handled, transferred, and examined a piece of evidence. For digital evidence, chain of custody includes...
- Decontamination
- The wash protocol applied to hair or nails before extraction, intended to remove sweat, sebum and external contamination so that the assay...
- Femoral Blood
- Peripheral venous blood drawn from the femoral vein after clamping it off proximally. Considered the gold-standard antemortem-equivalent matrix because it is anatomically...
- Matrix
- The biological tissue or fluid (or non-biological substance) in which the analyte is suspended. The matrix decides extraction chemistry, recovery and the...
- Phase I Metabolism
- Functionalisation reactions (oxidation, reduction, hydrolysis) that introduce or expose a polar group on the drug molecule, mostly catalysed by cytochrome P450 isoenzymes...
- Phase II Metabolism
- Conjugation reactions (glucuronidation, sulphation, glutathione conjugation, acetylation, methylation, glycine conjugation) that attach a polar endogenous group to the drug or its Phase...
- Saturated NaCl
- Sodium chloride dissolved in distilled water to saturation, roughly 360 g/L at room temperature. The default preservative for solid viscera in Indian...
Explained in these topics
- Biological, Non-Biological and Viscera Matrices in ToxicologyThe diffusion of drugs out of high-concentration tissue (heart, lung, liver) into adjacent blood after death. PMR can raise cardiac blood concentrations by 2 t...
- Drug Metabolism, Distribution and Metabolite IdentificationThe movement of drugs from tissue depots into central blood compartments after death, driven by passive diffusion as cell membranes lose integrity. Basic lipop...
- Post-Mortem Examination and Viscera Collection in PoisoningThe phenomenon where drug and poison concentrations shift between body compartments after death, generally moving out of solid organs back into the central blo...