Differences in amiodarone, digoxin, flecainide and sotalol concentrations between antemortem serum and femoral postmortem blood

Case report: An autopsy case of pilsicainide poisoning

We present a fatal case of pilsicainide poisoning. Quantitative toxicological analysis revealed that the concentrations of pilsicainide in femoral blood and urine samples were 17.5 μg/mL and 136.9 μg/mL, respectively. No morphological changes due to poisoning were observed. Based on the autopsy findings, results of the toxicological examination, and investigation by the authorities, we concluded that the cause of death was due to pilsicainide poisoning.

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.

The impact of the National Institute for Health Research Health Technology Assessment programme, 2003-13: a multimethod evaluation

BACKGROUND

The National Institute for Health Research (NIHR) Health Technology Assessment (HTA) programme supports research tailored to the needs of NHS decision-makers, patients and clinicians. This study reviewed the impact of the programme, from 2003 to 2013, on health, clinical practice, health policy, the economy and academia. It also considered how HTA could maintain and increase its impact.

METHODS

Interviews (n = 20): senior stakeholders from academia, policy-making organisations and the HTA programme. Bibliometric analysis: citation analysis of publications arising from HTA programme-funded research. Researchfish survey: electronic survey of all HTA grant holders. Payback case studies (n = 12): in-depth case studies of HTA programme-funded research.

RESULTS

We make the following observations about the impact, and routes to impact, of the HTA programme: it has had an impact on patients, primarily through changes in guidelines, but also directly (e.g. changing clinical practice); it has had an impact on UK health policy, through providing high-quality scientific evidence - its close relationships with the National Institute for Health and Care Excellence (NICE) and the National Screening Committee (NSC) contributed to the observed impact on health policy, although in some instances other organisations may better facilitate impact; HTA research is used outside the UK by other HTA organisations and systematic reviewers - the programme has an impact on HTA practice internationally as a leader in HTA research methods and the funding of HTA research; the work of the programme is of high academic quality - the Health Technology Assessment journal ensures that the vast majority of HTA programme-funded research is published in full, while the HTA programme still encourages publication in other peer-reviewed journals; academics agree that the programme has played an important role in building and retaining HTA research capacity in the UK; the HTA programme has played a role in increasing the focus on effectiveness and cost-effectiveness in medicine - it has also contributed to increasingly positive attitudes towards HTA research both within the research community and the NHS; and the HTA focuses resources on research that is of value to patients and the UK NHS, which would not otherwise be funded (e.g. where there is no commercial incentive to undertake research). The programme should consider the following to maintain and increase its impact: providing targeted support for dissemination, focusing resources when important results are unlikely to be implemented by other stakeholders, particularly when findings challenge vested interests; maintaining close relationships with NICE and the NSC, but also considering other potential users of HTA research; maintaining flexibility and good relationships with researchers, giving particular consideration to the Technology Assessment Report (TAR) programme and the potential for learning between TAR centres; maintaining the academic quality of the work and the focus on NHS need; considering funding research on the short-term costs of the implementation of new health technologies; improving the monitoring and evaluation of whether or not patient and public involvement influences research; improve the transparency of the priority-setting process; and continuing to monitor the impact and value of the programme to inform its future scientific and administrative development.

Amiodarone exposure during modest inflammation induces idiosyncrasy-like liver injury in rats: role of tumor necrosis factor-alpha

Amiodarone [2-butyl-3-(3′,5′-diiodo-4’α-diethylaminoethoxybenzoyl)-benzofuran] (AMD), a class III antiarrhythmic drug, is known to cause idiosyncratic hepatotoxic reactions in human patients. One hypothesis for the etiology of idiosyncratic adverse drug reactions is that a concurrent inflammatory stress results in decreased threshold for drug toxicity. To explore this hypothesis in an animal model, male Sprague-Dawley rats were treated with nonhepatotoxic doses of AMD or its vehicle and with saline vehicle or lipopolysaccharide (LPS) to induce low-level inflammation. Elevated alanine aminotransferase (ALT), aspartate aminotransferase, alkaline phosphatase, and gamma-glutamyltransferase activities as well as increased total bile acid concentrations in serum and midzonal hepatocellular necrosis were observed only in AMD/LPS-cotreated rats. The time interval between AMD and LPS administration was critical: AMD injected 16 h before LPS led to liver injury, whereas AMD injected 2–12 h before LPS failed to cause this response. The increase in ALT activity in AMD/LPS cotreatment showed a clear dose-response relationship with AMD as well as LPS. The metabolism and hepatic accumulation of AMD were not affected by LPS coexposure. Serum concentration of tumor necrosis factor-alpha (TNF) was significantly increased by LPS and was slightly prolonged by AMD. In Hepac1c7 cells, addition of TNF potentiated the cytotoxicity of both AMD and its primary metabolite, mono-N-desethylamiodarone. In vivo inhibition of TNF signaling by etanercept attenuated the AMD/LPS-induced liver injury in rats. In summary, AMD treatment during modest inflammation induced severe hepatotoxicity in rats, and TNF contributed to the induction of liver injury in this animal model of idiosyncratic AMD-induced liver injury.

Post-mortem clinical pharmacology

Clinical pharmacology assumes that deductions can be made about the concentrations of drugs from a knowledge of the pharmacokinetic parameters in an individual; and that the effects are related to the measured concentration. Post-mortem changes render the assumptions of clinical pharmacology largely invalid, and make the interpretation of concentrations measured in post-mortem samples difficult or impossible. Qualitative tests can show the presence of substances that were not present in life, and can fail to detect substances that led to death. Quantitative analysis is subject to error in itself, and because post-mortem concentrations vary in largely unpredictable ways with the site and time of sampling, as a result of the phenomenon of post-mortem redistribution. Consequently, compilations of 'lethal concentrations' are misleading. There is a lack of adequate studies of the true relationship between fatal events and the concentrations that can be measured subsequently, but without such studies, clinical pharmacologists and others should be wary of interpreting post-mortem measurements.

Post-mortem redistribution of three beta-blockers in the rabbit

To consider the role of the physico-chemical properties of drugs in their post-mortem redistribution, we designed the present study to investigate the influence of lipophilicity using an experimental rabbit model. Three beta-blockers (BB), atenolol, metoprolol and propranolol, with a similar dissociation constant (pK (a)) and increasing partition coefficient (K (p)) were administered intravenously to 18 rabbits. One hour after the last administration, the animals were killed by thiopental injection and placed in a supine position at room temperature. Autopsies were performed at 0, 2, 6, 12, 24 and 48 h post-mortem. Concentrations of the three BB were determined in fluids (right and left cardiac blood, peripheral blood, urine, bile, stomach content, vitreous humour) and tissues (cardiac muscle, lungs, liver, brain, diaphragm, iliopsoas muscle) using a previously published, validated liquid chromatography-electrospray-mass spectrometry method. Our results show that lipophilicity influences post-mortem redistribution of the molecules in a certain number of anatomical sites such as the stomach, lungs, cardiac muscle, cardiac blood or liver, but does not appear to intervene in other sites such as the brain or the vitreous humour.

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.

Preanalytic aspects in postmortem toxicology

The preanalytic phase has been recognized to have a substantial role for the quality and reliability of analytical results, which very much depend on the type and quality of specimens provided. There are several unique challenges to select and collect specimens for postmortem toxicology investigation. Postmortem specimens may be numerous, and sample quality may be quite variable. An overview is given on specimens routinely collected as well as on alternative specimens that may provide additional information on the route of administration, a long term or a recent use/exposure to a drug or poison. Autolytic and putrefactive changes limit the selection and utility of specimens. Some data from case reports as well as experimental investigations on drug degradation and/or formation during putrefaction are discussed. Diffusion processes as well as postmortem degradation or formation may influence ethanol concentration in autopsy specimens. Formalin fixation of specimens or embalmment of the corpse may cause considerable changes of initial drug levels. These changes are due to alterations of the biological matrix as well as to dilution of a sample, release or degradation of the drug or poison. Most important seems a conversion of desmethyl metabolites to the parent drug. Some general requirements for postmortem sampling are given based on references about specimen collection issues, for a harmonized protocol for sampling in suspected poisonings or drug-related deaths does not exist. The advantages and disadvantages of specimen preservation are shortly discussed. Storage stability is another important issue to be considered. Instability can either derive from physical, chemical or metabolic processes. The knowledge on degradation mechanisms may enable the forensic toxicologist to target the right substance, which may be a major break down product in the investigation of highly labile compounds. Although it is impossible to eliminate all interfering factors or influences occurring during the preanalytic phase, their consideration should facilitate the assessment of sample quality and the analytical result obtained from that sample.

Post-mortem toxicology: what the dead can and cannot tell us

The evaluation of postmortem laboratory assays of drugs needs to be performed in a systematic manner. The condition of the body, drug characteristics, matrix and site analysis are factors which need to be considered in the proper interpretation of an autopsy specimen result.

Flecainide toxicity: cause and contribution to death

In this report, we describe in detail one fatality in which flecainide toxicity was considered to be the primary cause of death and discuss the possible contribution of flecainide in another case. The concentration of flecainide in postmortem specimens is discussed in relation to other drugs as well as some of the difficulties associated with the interpretation of postmortem drug levels.

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.

Fatal flecainide intoxication

A fatal case attributed to flecainide acetate (Tambocor), a class Ic antiarrythmic drug, is presented. Flecainide was detected by GC/MS in gastric contents, blood and liver as well. The urine analysis revealed the presence of its dealkylated metabolite. Body fluids and tissue concentrations determined by GC/ECD were 7.7 mg/kg in femoral blood, 0.26 mg/kg in bile, 18 mg/kg in liver, 0.17 mg/kg in cerebrospinal fluid, 0.22 mg/kg in brain cortex and 28.9 mg/kg in urine. The total amount of flecainide in gastric contents was about 43 mg. Even taking into account the postmortem redistribution of flecainide, its blood level still remains in the toxic range.

Postmortem digoxin-like immunoreactive substances (DLIS) in patients not treated with digoxin

Endogenous digoxin-like immunoreactive substances (DLIS) cross-react in immunoassays of digoxin. The postmortem rise in digoxin levels in patients treated with the drug may be due to its redistribution. It is unclear what is the contribution of DLIS to this increase and whether DLIS are present postmortem in patients not treated with digoxin. The objectives of this study were to determine whether DLIS are present after death in patients not treated with digoxin, whether a postmortem increase in DLIS is detectable and whether sampling site can affect DLIS concentrations. DLIS (measured as digoxin, TDx Abott) were determined in blood samples drawn antemortem from ICU patients; postmortem samples from femoral artery and cardiac chambers were taken at least 12 h after the death of these same patients. DLIS concentrations > or = 0.2 ng/ml were measured in 44 and 40% of patients antemortem and postmortem (femoral), respectively. No difference was found in DLIS levels between antemortem and postmortem femoral and cardiac samples. Age, ICU stay and postmortem sampling time did not affect the postmortem increase in DLIS. None of the levels was in the toxic range. DLIS may be present after death and their concentration does not increase postmortem. The interpretation of postmortem digoxin concentrations that fall in the therapeutic range should be done cautiously; such measurable levels do not necessarily indicate misuse or malicious intent even in patients who had not been treated with the drug.