Postmortem Drug Redistribution: A Compilation of Postmortem/Antemortem Drug Concentration Ratios

Postmortem drug redistribution (PMR) is a well-known phenomenon in forensic toxicology with implications for medico-legal death investigations. Paired antemortem (AM) specimen and postmortem (PM) mortuary admission femoral blood drug concentrations from 811 coronial cases were used to construct a retrospective compilation of PM/AM drug concentration ratios for 42 parent drugs and metabolites. The median PM/AM ratios for all antidepressants were > 1 and consistent with PMR In contrast, the median PM/AM ratios of most benzodiazepines were < 1. The antipsychotics were varied (0.63-3.3) and suggest the mixed effects of PMR and drug instability. Amphetamines exhibited no trends (0.90-0.95) and are likely confounded by many factors. The PM/AM ratios of cardiovascular drugs, opioids and other drugs are also reported. This research represents an expansive retrospective compilation of paired AM and PM drug concentrations for many toxicologically relevant drugs. While the median PM/AM ratios demonstrate some drug-dependent trends, there was no obvious relationship between AM specimens and PM femoral blood taken at mortuary admission.

Oxycodone Concentrations and Metabolic Ratios in Femoral Blood from Fatal Intoxications and Other Causes of Death using LC-MS-MS

Oxycodone (OC) is an opioid with strong analgesic effects widely used to treat acute and chronic pain. Interpretation of OC concentrations in postmortem cases is complicated due to tolerance and overlapping concentrations for fatal and non-fatal levels. In this study, our aim was to develop and validate a method for OC and its three metabolites: noroxycodone (NOC), oxymorphone (OM) and noroxymorphone (NOM) in postmortem femoral blood. Our goal was to define reference concentrations for intoxications and non-intoxications and investigate metabolic ratios in different causes of death. A rapid LC-MS-MS method using protein-precipitated postmortem blood was developed. Lower limit of quantitation was 0.005 μg/g blood for all analytes; upper limit of quantitation was 1.0 μg/g for OC and NOC and 0.25 μg/g for OM and NOM. The method displayed high precision (3.3-7.7%) and low bias (-0.3 to 12%). In total, 192 cases were analyzed and concentrations ranged from 0.005 to 13 μg/g for OC, 0.005 to 2.0 μg/g for NOC, 0.005 to 0.24 μg/g for OM, and 0.005 to 0.075 μg/g for NOM. We found a significant difference in OC concentration between the cases where OC contributed and those where it did not. In spite of that, we do not recommend the use of a specific blood concentration to distinguish fatal intoxications. Instead, the percentiles from our data set suggest that concentrations >0.2 μg/g are likely to have contributed to toxicity, but that concentrations as high as 0.3 might be tolerated without toxic effects. In addition, we also found that a low NOC/OC ratio could point toward an acute fatal intoxication. In conclusion, the OC concentration alone may not be sufficient to diagnose a fatal intoxication.

Postmortem Brain-Blood Ratios of Codeine, Fentanyl, Oxycodone and Tramadol

The analgesics, codeine, fentanyl, oxycodone and tramadol, frequently occur in postmortem cases and determining their role in the cause of death can be challenging. However, postmortem blood is susceptible to redistribution and may not be available in cases of severe blood loss, putrefaction or burns. Brain tissue may serve as a viable supplement to blood or on its own, as it is resistant to postmortem redistribution and often available as a sample matrix when blood is not available. We present brain and blood concentrations and brain-blood ratios of the four analgesics from 210 autopsy cases. The cases were classified according to the presumed cause of death: A: The compound was believed to have solely caused a fatal intoxication. B: The compound was assumed to have contributed to a fatal outcome in combination with other drugs, alcohol or disease. C: The compound was not regarded as being related to the cause of death. Blood and brain samples were prepared by automatic solid phase extraction and quantified by liquid chromatography-mass spectrometry. The squared correlation coefficients between concentrations in brain tissue and blood ranged 0.45-0.91. The median brain-blood ratios were codeine 1.8 (range 0.47-4.6), fentanyl 2.1 (range 0.29-16), oxycodone 1.8 (range 0.11-6.0) and tramadol 1.8 (range 0.047-6.8). A significantly higher brain-blood ratio of codeine was observed in cases where heroin had been administered, although there was a wide overlap. Intravenous and transdermal fentanyl administration could not be distinguished based on the blood or brain concentration or the brain-blood ratio. The results of this study may benefit the toxicological investigation in postmortem cases where one of the four analgesics are suspected of having contributed to or caused a fatal intoxication.

Position Paper: Recommendations for the Investigation, Diagnosis, and Certification of Deaths Related to Opioid and Other Drugs

The National Association of Medical Examiners convened an expert panel to update the association's evidence-based recommendations for investigating and certifying deaths associated with opioids and other misused substances to improve death certificate and mortality data for public health surveillance. The recommendations are as follows:1. Autopsy provides the best information on a decedent's medical condition for optimal interpretation of toxicology results, circumstances surrounding death, medical history, and scene findings. The panel considers autopsy an essential component of investigating apparent overdose deaths.2. Scene investigation includes reconciling prescription information and medication counts. Investigators should note drug paraphernalia or other evidence of using intoxicating substances.3. Retain blood, urine, and vitreous humor whenever available. Blood from the iliofemoral vein is preferable to blood from more central sites.4. A toxicological panel should be comprehensive, including potent depressant, stimulant, and antidepressant medications. Detecting novel substances present in the community may require special testing.5. When death is attributed to a drug or combination of drugs (as cause or contributing factor), the certifier should list the drugs by generic name in the autopsy report and death certificate.6. The best classification for manner of death in an overdose without any apparent intent of self-harm is "accident."

A Novel Bioanalytical Method for the Determination of Opioids in Blood and Pericardial Fluid

Opioids are the drugs most commonly detected in overdose deaths and the second most consumed worldwide. An analytical methodology has been optimized and fully validated for the determination of codeine, morphine, 6-acetylmorphine, 6-acetylcodeine, oxycodone, oxymorphone and fentanyl in whole blood and pericardial fluid. The internal standards used were codeine-d3, morphine-d3, 6-acetylmorphine-d3 and fentanyl-d5. Before solid-phase extraction, volumes of 250 μL of blood and pericardial fluid were subjected to a protein precipitation (with 750 μL of ice-cold acetonitrile) and a microwave-induced oximation was performed using a solution of 1% aqueous hydroxylamine hydrochloride in phosphate-buffered saline (1:2, v/v). Finally, the dried extracts were further derivatized with a solution of n-methyl-n-(trimethylsilyl) trifluoroacetamide + 5% trimethylchlorosilane under microwave irradiation. The chromatographic analysis was carried out using gas chromatography–mass spectrometry operating in electron impact and selected ion monitoring mode. For all analytes, the method was linear between 5 and 1,000 ng/mL with determination coefficients (r2) &gt;0.99. Depending on the analyte and matrix, the limit of detection varies between 3 and 4 ng/mL. Intra- and intermediate precision (&lt;20%) and bias (±20%) were acceptable for all analytes in both matrices. The stability of the substances in the studied matrices was guaranteed, at least, 24 h in the autosampler, 4 h at room temperature and 30 days after three freeze/thaw cycles. This methodology was applied to real samples from the Laboratory of Chemistry and Forensic Toxicology, Centre Branch, of the National Institute of Legal Medicine and Forensic Sciences, Portugal.

Ethanol Reversal of Tolerance to the Antinociceptive Effects of Oxycodone and Hydrocodone

This study compared the development of tolerance to two orally bioavailable prescription opioids, oxycodone and hydrocodone, to that of morphine, and the reversal of this tolerance by ethanol. Oxycodone (s.c.) was significantly more potent in the mouse tail-withdrawal assay than either morphine or hydrocodone. Oxycodone was also significantly more potent in this assay than hydrocodone when administered orally. Tolerance was seen following chronic subcutaneous administration of each of the three drugs and by the chronic administration of oral oxycodone, but not following the chronic oral administration of hydrocodone. Ethanol (1 g/kg i.p.) significantly reversed the tolerance to the subcutaneous administration of each of the three opioids that developed when given 30 minutes prior to challenge doses. It took twice as much ethanol, when given orally, to reverse the tolerance to oxycodone. We investigated whether the observed tolerance to oxycodone and its reversal by ethanol were due to biodispositional changes or reflected a true neuronal tolerance. As expected, a relationship between brain oxycodone concentrations and activity in the tail-immersion test existed following administration of acute oral oxycodone. Following chronic treatment, brain oxycodone concentrations were significantly lower than acute concentrations. Oral ethanol (2 g/kg) reversed the tolerance to chronic oxycodone, but did not alter brain concentrations of either acute or chronic oxycodone. These studies show that there is a metabolic component of tolerance to oxycodone; however, the reversal of that tolerance by ethanol is not due to an alteration of the biodisposition of oxycodone, but rather is neuronal in nature.

Complete republication: National Association of Medical Examiners position paper: Recommendations for the investigation, diagnosis, and certification of deaths related to opioid drugs

The American College of Medical Toxicology and the National Association of Medical Examiners convened an expert panel to generate evidence-based recommendations for the practice of death investigation and autopsy, toxicological analysis, interpretation of toxicology findings, and death certification to improve the precision of death certificate data available for public health surveillance. The panel finds the following: 1. A complete autopsy is necessary for optimal interpretation of toxicology results, which must also be considered in the context of the circumstances surrounding death, medical history, and scene findings. 2. A complete scene investigation extends to reconciliation of prescription information and pill counts. 3. Blood, urine, and vitreous humor, when available, should be retained in all cases. Blood from the femoral vein is preferable to blood from other sites. 4. A toxicological panel should be comprehensive and include opioid and benzodiazepine analytes, as well as other potent depressant, stimulant, and anti-depressant medications. 5. Interpretation of postmortem opioid concentrations requires correlation with medical history, scene investigation, and autopsy findings. 6. If death is attributed to any drug or combination of drugs (whether as cause or contributing factor), the certifier should list all the responsible substances by generic name in the autopsy report and on the death certificate. 7. The best classification for manner of death in deaths due to the misuse or abuse of opioids without any apparent intent of self-harm is "accident." Reserve "undetermined" as the manner for the rare cases in which evidence exists to support more than one possible determination.

National Association of Medical Examiners Position Paper: Recommendations for the Investigation, Diagnosis, and Certification of Deaths Related to Opioid Drugs

The American College of Medical Toxicology and the National Association of Medical Examiners convened an expert panel to generate evidence-based recommendations for the practice of death investigation and autopsy, toxicological analysis, interpretation of toxicology findings, and death certification to improve the precision of death certificate data available for public health surveillance. The panel finds the following: 1. A complete autopsy is necessary for optimal interpretation of toxicology results, which must also be considered in the context of the circumstances surrounding death, medical history, and scene findings. 2. A complete scene investigation extends to reconciliation of prescription information and pill counts. 3. Blood, urine, and vitreous humor, when available, should be retained in all cases. Blood from the femoral vein is preferable to blood from other sites. 4. A toxicological panel should be comprehensive and include opioid and benzodiazepine analytes, as well as other potent depressant, stimulant, and anti-depressant medications. 5. Interpretation of postmortem opioid concentrations requires correlation with medical history, scene investigation, and autopsy findings. 6. If death is attributed to any drug or combination of drugs (whether as cause or contributing factor), the certifier should list all the responsible substances by generic name in the autopsy report and on the death certificate. 7. The best classification for manner of death in deaths due to the misuse or abuse of opioids without any apparent intent of self-harm is “accident.” Reserve “undetermined” as the manner for the rare cases in which evidence exists to support more than one possible determination.

Recommendations for the Investigation, Diagnosis, and Certification of Deaths Related to Opioid Drugs

The American College of Medical Toxicology and the National Association of Medical Examiners convened an expert panel to generate evidence-based recommendations for the practice of death investigation and autopsy, toxicological analysis, interpretation of the toxicology findings, and death certification to improve the precision of death certificate data available for public health surveillance. The panel finds the following: 1. A complete autopsy is necessary for optimal interpretation of toxicology results, which must also be considered in the context of the circumstances surrounding death, medical history, and scene findings. 2. A complete scene investigation extends to reconciliation of prescription information and pill counts. 3. Blood, urine, and vitreous humor, when available, should be retained in all cases. Blood from the femoral vein is preferable to blood from other sites. 4. A toxicological panel should be comprehensive and include opioid and benzodiazepine analytes, as well as other potent depressant, stimulant, and antidepressant medications. 5. Interpretation of postmortem opioid concentrations requires correlation with medical history, scene investigation, and autopsy findings. 6. If death is attributed to any drug or combination of drugs (whether as cause or contributing factor), the certifier should list all the responsible substances by generic name in the autopsy report and on the death certificate. 7. The best classification for manner in deaths due to the misuse or abuse of opioids without any apparent intent of self-harm is “accident.” Reserve “undetermined” as the manner for the rare cases in which evidence exists to support more than one possible determination.

Oxycodone overdose causes naloxone responsive coma and QT prolongation

BACKGROUND

Although there are limited data on oxycodone overdose, it has been suggested that, in addition to central nervous system (CNS) depression, oxycodone may cause QT prolongation. Given the high prescription rate and increasing use of oxycodone, an understanding of its effects and treatment in overdose is necessary.

AIM

To investigate the clinical features, electrocardiogram (ECG) parameters and treatment of oxycodone overdose.

DESIGN

Retrospective review of a clinical database.

METHODS

One hundred and thirty-seven oxycodone overdoses were identified from admissions to a toxicology unit between January 2001 and May 2011. Demographic information, details of ingestion, clinical effects, ECG parameters [heart rate (HR), QT and QRS], naloxone use and length of stay (LOS) were extracted from a clinical database. QT was measured manually and plotted on a QT nomogram. LOS was extracted for all overdoses over the same period.

RESULTS

From 137 oxycodone overdoses, 79 (58%) ingested immediate release (IR) and 58 (42%) ingested sustained release (SR) or a combination of IR and SR. The median age was 40 years [interquartile range (IQR): 33-49 years], and 87 were female (64%). The median ingested dose of IR oxycodone was 70 mg (IQR: 40-100, range: 5-200), compared to 240 mg (IQR: 80-530, range: 30-1600) for SR oxycodone. Benzodiazepines were the most frequent co-ingested drug in 52 (38%) cases. No arrhythmias were recorded. Twenty-four patients (18%) had bradycardia of which five had a HR < 50 beats/min. From 116 available ECGs, the median QRS was 95 ms (IQR: 90-102 ms), and there were 20 (17%) abnormal QT-HR pairs. Naloxone boluses were required in 65 admissions (47%), and 34 (25%) required a naloxone infusion. There was higher overall naloxone use with SR and IR + SR (32/58, 55%) compared to IR oxycodone (33/79, 42%). The median LOS was 18 h (IQR: 12-35), which was greater than the median LOS for all toxicology admissions at 15 h (IQR: 8-24) over the same period. Patients requiring a naloxone infusion had an even greater LOS of 36 h (IQR: 20-62 h).

CONCLUSION

In addition to the expected CNS depression, the opioid oxycodone can cause bradycardia and QT prolongation in overdose. The SR formulation is associated with the use of naloxone infusions and a longer LOS.