Post-mortem toxico-kinetics of trazodone

Forensic Aspects of a Fatal Intoxication Involving Acetaminophen, Citalopram and Trazodone: A Case Report

We report the case of a young man, a former heroin addict, found dead at home by the Police Forces in an advanced state of decomposition. Numerous blisters and unpacked tablets of medications were found all over the bed and on the floor of the room. Multiple injuries to the face, left arm and neck of the deceased were noted. The latter damages were attributed to post-mortem dog bites, since no indications of a possible defense against the animal were observed. The autopsy findings were unremarkable. Toxicological investigations performed on peripheral blood and urine by gas chromatography-mass spectrometry (GC-MS) technique showed the presence of acetaminophen, citalopram and trazodone. Combined drug intoxication was proposed as the cause of death since acetaminophen and trazodone concentrations were comparable with the ones found in fatal cases. Moreover, citalopram concentration in peripheral blood was above the toxic range and in accordance with levels found in fatalities due to poly-drug intoxication.

A target concentration strategy to determine ibuprofen dosing in children

BACKGROUND

Ibuprofen is widely used for ductus arteriosus closure in premature neonates and for analgesia in children and adults. There are no maturation descriptors of clearance. This lack of maturation understanding limits dosing recommendations from premature neonates to adulthood.

METHODS

Published clearance estimates from different aged patients determined after administration from time-concentration profiles were used to construct a maturation model based on size and age. Curve fitting was performed using nonlinear mixed-effects models. A target concentration strategy was used to estimate maintenance dose at different ages.

RESULTS

There were three publications reporting an estimate of individual clearance estimates in premature neonates, three reporting population clearances in infants, 11 in children 2-15 years (1 with individual and 9 with population clearances), and 13 adult studies (1 with individual and 12 with population clearances). Clearance maturation, standardized to a 70 kg person was described using the Hill equation. Mature clearance was 3.81 (CV 15.5%, 95%CI 3.72, 3.92) L/h/70 kg. The maturation half-time was 36.8 (CV 9.2%, 95%CI 34.7, 40.9) weeks postmenstrual age and the Hill coefficient 11.5 (95%CI 8.1, 15). A target effect of four units (visual analogue scale 0-10) correlated with an effect site concentration of 6.3 mg/L: a concentration achieved at trough after 400 mg 8 hourly in adults.

CONCLUSION

Previously published pharmacokinetic parameters can be used to develop maturation models that address gaps in current knowledge regarding the influence of age on a drug's disposition. Maturation of ibuprofen clearance was rapid and was 90% of adult values by the first month of life in term neonates (ie, 44 weeks postmenstrual age) and 98% of standardized adult estimates by 3 months of age (53 weeks postmenstrual age). Clearance informed dosing predictions in all ages (premature neonate to adult) and matched those doses in common use in children older than 3 months.

Determination of Antidepressants and Antipsychotics in Dried Blood Spots (DBSs) Collected from Post-Mortem Samples and Evaluation of the Stability over a Three-Month Period

An LC-MS/MS method for the identification and quantification of antidepressants and antipsychotics was developed on dried blood spots (DBSs). Moreover, analyte stability on DBSs within a 3-month period was monitored. Aliquots of 85 µL of blood from autopsy cases were pipetted onto DBS cards, which were dried and stored at room temperature. DBSs were analyzed in triplicate immediately, within the following 3 weeks, and after 3 months. For each analysis, a whole blood stain was extracted in phosphate buffer and purified using Solid Phase Extraction (SPE) cartridges in order to avoid matrix effects and injected in the LC-MS/MS system. Thirty-nine molecules were screened. Limits of detection (LODs) ranged between 0.1 and 3.2 ng/mL (g) and 0.1 and 5.2 ng/mL (g) for antidepressants and antipsychotics, respectively. Limits of quantification (LOQs) varied from 5 to 10.0 ng/mL for both. Sixteen cases among the 60 analyzed resulted positive for 17 different analytes; for 14 of these the method was fully validated. A general good agreement between the concentrations on DBSs and those measured in conventional blood samples (collected concurrently and stored at -20 °C) was observed. The degradation/enhancement percentage for most of the substances was lower than 20% within the 3-month period. Our results, obtained from real post-mortem cases, suggest that DBSs can be used for routine sample storage.

Plasma vs heart tissue concentration in humans - literature data analysis of drugs distribution

Little is known about the uptake of drugs into the human heart, although it is of great importance nowadays, when science desires to predict tissue level behavior rather than to measure it. Although the drug concentration in cardiac tissue seems a better predictor for physiological and electrophysiological changes than its level in plasma, knowledge of this value is very limited. Tissue to plasma partition coefficients (Kp) come to rescue since they characterize the distribution of a drug among tissues as being one of the input parameters in physiologically based pharmacokinetic (PBPK) models. The article reviews cardiac surgery and forensic medical studies to provide a reference for drug concentrations in human cardiac tissue. Firstly, the focus is on whether a drug penetrates into heart tissue at a therapeutic level; the provided values refer to antibiotics, antifungals and anticancer drugs. Drugs that directly affect cardiomyocyte electrophysiology are another group of interest. Measured levels of amiodarone, digoxin, perhexiline and verapamil in different sites in human cardiac tissue where the compounds might meet ion channels, gives an insight into how these more lipophilic drugs penetrate the heart. Much data are derived from postmortem studies and they provide insight to the cardiac distribution of more than 200 drugs. The analysis depicts potential problems in defining the active concentration location, what may indirectly suggest multiple mechanisms involved in the drug distribution within the heart. Copyright © 2015 John Wiley & Sons, Ltd.

The evaluation of doxepin concentrations in postmortem blood as optional cause of death

The problems concerning an unstable data basis with regard to lethal Doxepin concentrations have been manifested based on a case about a 39-year-old man, who was found dead in his apartment with strangulation marks on his neck, for which a lethal Doxepin intoxication entered the differential diagnosis discussion. For a long time it has been known that postmortem redistribution leads to a falsely inflated concentration as measured in cardiac blood, while the concentrations in peripheral postmortem blood change comparatively little. Despite this, most of the current literature relies on published case report, which fails to mention the location of blood sampling, whereby it is fairly safe to assume that a central sample is intended. Only 9 cases of an isolated lethal Doxepin intoxication have been found, in which the concentrations in blood samples from peripheral vessels had been measured. These values lie between 1.5 and 7.0 mg/L, which is in the lowest quarter of the span of lethal concentrations mentioned in literature without specific mention of the location of the blood sample.

Interpretation of analytical toxicology results in life and at postmortem

Interpretation of analytical toxicology results from live patients is sometimes difficult. Possible factors may be related to: (i) the nature of the poison(s) present; (ii) sample collection, transport and storage; (iii) the analytical methodology used; (iv) the circumstances of exposure; (v) mechanical factors such as trauma or inhalation of stomach contents; and (vi) pharmacological factors such as tolerance or synergy. In some circumstances, detection of a drug or other poison may suffice to prove exposure. At the other extreme, the interpretation of individual measurements may be simplified by regulation. Examples here include whole blood alcohol (ethanol) in regard to driving a motor vehicle and blood lead assays performed to assess occupational exposure. With pharmaceuticals, the plasma or serum concentrations of drugs and metabolites attained during treatment often provide a basis for the interpretation of quantitative measurements. With illicit drugs, comparative information from casework may be all that is available. Postmortem toxicology is an especially complex area since changes in the composition of fluids such as blood depending on the site of collection from the body and the time elapsed since death, amongst other factors, may influence the result obtained. This review presents information to assist in the interpretation of analytical results, especially regarding postmortem toxicology. Collection and analysis of not only peripheral blood, but also other fluids/tissues is usually important in postmortem work. Alcohol, for example, can be either lost from, or produced in, blood especially if there has been significant trauma, hence measurements in urine or vitreous humour are needed to confirm the reliability of a blood result. Measurement of metabolites may also be valuable in individual cases.

Fatal blood and tissue concentrations of more than 200 drugs

Fatal drug concentrations in body fluids and tissue samples are presented for more than 200 drugs and chemicals of toxicologic interest. Additionally, a reference list is added with more than 600 original papers concerning intoxications with a lethal outcome. The data can be helpful for the interpretation and plausibility control in own cases of intoxication. However, they should be used with caution, because use of drug data without sufficient knowledge about the patient or victim, the circumstances of the case, and about toxicokinetics and toxicodynamics might give a wrong interpretation in a special case.

Treatment of sleep disturbance in alcohol recovery: a national survey of addiction medicine physicians

Sleep disturbance is common among patients in recovery from alcoholism and can precipitate relapse. Though sleep complaints are commonly managed with medication, little is known about their management among recovering alcoholic patients. We performed a postal survey of a self-weighted, random systematic sample of 503 members of the American Society of Addiction Medicine (ASAM) to examine addiction medicine physicians' medical management of sleep disturbance among patients in early recovery from alcoholism. After 3 mailings, 311 (62%) responded. Of responents, 64% have offered pharmacological treatment to an insomniac, alcoholic patient in the first 3 months after detoxification, but only 22% offered medication to more than half of such patients. Trazodone was the preferred therapy, chosen first by 38% of respondents, followed by other sedating antidepressants (12%), and antihistamines (12%). The mean duration of therapy for trazodone and other sedating antidepressants exceeded one month. Experts in addiction medicine appear reluctant to prescribe medication to sleep-disturbed patients in early recovery from alcoholism. When they do prescribe, trazodone, other sedating antidepressants and antihistamines are favored, despite limited evidence for or against this indication. Although the treatment of disordered sleep among alcoholic patients in early recovery may have merit to prevent relapse, controlled studies of these sleep agents are needed.

Estimating antemortem drug concentrations from postmortem blood samples: the influence of postmortem redistribution

AIMS

To compare blood drug concentrations during life with postmortem drug concentrations measured from a peripheral site and a central site.

METHODS

Coroner's cases from October 1990 to July 1997 were reviewed. Six cases had data on both antemortem and postmortem blood drug concentrations. The postmortem to antemortem ratio was compared with the postmortem central to peripheral ratio, using cardiac blood as a central site and femoral blood as a peripheral site.

RESULTS

Drugs that have a high postmortem central to peripheral ratio; that is, drugs that exhibit considerable postmortem redistribution, also have high postmortem to antemortem ratios.

CONCLUSIONS

A large degree of error can arise from attempting to estimate antemortem drug concentrations and the ingested dose from postmortem measurements. The chosen site and technique for postmortem blood sampling can greatly influence the concentration of drug measured.

Postmortem changes in blood tranylcypromine concentration: competing redistribution and degradation effects

Site and temporal changes in tranylcypromine (TCP) and lithium concentrations in blood were studied in a human poisoning case. Blood samples from peripheral vessels and six central vessels were obtained at 0, 6, 24, 48 and 72 h after starting the autopsy. Nine tissue samples were obtained on completion. TCP showed preferential concentration in liver (2.21 micrograms/g) and brainstem (2.46 micrograms/g). There was a moderate post mortem redistribution phenomenon with TCP concentrations lowest in peripheral blood (0.17 micrograms/ml) at 0 h and highest in central vessels at 24 h (0.52 micrograms/ml). At 72 h blood TCP concentrations fell below those at 0 time but the samples showed marked putrefactive changes. Control blood samples spiked with TCP and incubated for 48 h at 37 degrees C showed a 58% fall in drug concentration. By contrast with TCP, lithium, which has a small Vd (0.8 l/kg) and is chemically stable, did not show this pattern of change in blood concentration. The site and temporal differences in TCP concentration in blood can be explained by the competing effects of post mortem redistribution and drug degradation. Redistribution is an early post mortem phenomenon characterised by diffusion, along a concentration gradient, from drug reservoirs in solid organs into adjacent blood vessels. Drug degradation is a later phenomenon associated with putrefactive change.