Effect of the UK's revised paracetamol poisoning management guidelines on admissions, adverse reactions and costs of treatment

Patterns of acetaminophen toxicity among patients with low-risk serum concentrations

OBJECTIVE

In 2012, the Commission on Human Medicines mandated lowering the acetaminophen toxicity nomogram treatment threshold in the UK to 100 µg/ml at 4 h post-ingestion. The present study aim was to evaluate biochemical and liver toxicity patterns in patients who presented with acetaminophen overdose and had low serum acetaminophen concentrations (<150 µg/ml).

METHODS

Patients admitted to the emergency department with a clear history of acute acetaminophen overdose with or without other medication or ethanol were consecutively enrolled into this retrospective cohort study. Patients with serum acetaminophen concentration >150 µg/ml or an unknown ingestion time were excluded. Data were extracted from electronic medical records and are presented as mean ± SD or median (interquartile range).

RESULTS

A total of 103 patients were included (median age, 17 [4-21] years) and 80 (78%) were female. The median ingested acetaminophen dose was 5000 (2850-7650) mg. At baseline, the median serum acetaminophen concentration was 42 (4.5-64.8) µg/ml, and median alanine aminotransferase and aspartate aminotransferase levels were 22 (17-28) and 27 (16-45) IU/L, respectively. Twenty patients were treated with acetylcysteine, with none developing adverse reactions. No patient developed hepatotoxicity, including patients with initial multiple product ingestion or other risk factors.

CONCLUSIONS

Patients presenting with an acute acetaminophen overdose with acetaminophen level <150 µg/ml, including patients with other risk factors, are at low risk of hepatotoxicity.

Clinically relevant therapeutic approaches against acetaminophen hepatotoxicity and acute liver failure

Liver injury and acute liver failure caused by an acetaminophen (APAP) overdose is a significant clinical problem in western countries. With the introduction of the mouse model of APAP hepatotoxicity in the 1970 s, fundamental mechanisms of cell death were discovered. This included the recognition that part of the APAP dose is metabolized by cytochrome P450 generating a reactive metabolite that is detoxified by glutathione. After the partial depletion of glutathione, the reactive metabolite will covalently bind to sulfhydryl groups of proteins, which is the initiating event of the toxicity. This insight led to the introduction of N-acetyl-L-cysteine, a glutathione precursor, as antidote against APAP overdose in the clinic. Despite substantial progress in our understanding of the pathomechanisms over the last decades viable new antidotes only emerged recently. This review will discuss the background, mechanisms of action, and the clinical prospects of the existing FDA-approved antidote N-acetylcysteine, of several new drug candidates under clinical development [4-methylpyrazole (fomepizole), calmangafodipir] and examples of additional therapeutic targets (Nrf2 activators) and regeneration promoting agents (thrombopoietin mimetics, adenosine A2B receptor agonists, Wharton's Jelly mesenchymal stem cells). Although there are clear limitations of certain therapeutic approaches, there is reason to be optimistic. The substantial progress in the understanding of the pathophysiology of APAP hepatotoxicity led to the consideration of several drugs for development as clinical antidotes against APAP overdose in recent years. Based on the currently available information, it is likely that this will result in additional drugs that could be used as adjunct treatment for N-acetylcysteine.

Paracetamol (acetaminophen) poisoning: The early years

Paracetamol (acetaminophen) was marketed in the 1950s as a nonprescription analgesic/antipyretic without any preclinical toxicity studies. It became used increasingly for self-poisoning, particularly in the UK and was belatedly found to cause acute liver damage, which could be fatal. Management of poisoned patients was difficult as maximum abnormalities of liver function were delayed for 3 days or more after an overdose. There was no treatment and the mechanism of hepatotoxicity was not known. The paracetamol half-life was prolonged with liver damage occurring when it exceeded 4 h and the Rumack-Matthew nomogram was an important advance that allowed stratification of patients into separate zones of risk. It is used to guide prognosis and treatment and its predictive value could be increased by combining it with the paracetamol half-life. The problems of a sheep farmer in Australia in the early 1970s led to the discovery of the mechanism of paracetamol hepatotoxicity, and the first effective treatment of overdosage with intravenous (IV) cysteamine. This had unpleasant side effects and administration was difficult. N-acetylcysteine soon became the treatment of choice for paracetamol overdose and given early it was very effective when administered either IV or orally. N-acetylcysteine could cause anaphylactoid reactions, particularly early during IV administration when the concentrations were highest. Simpler and shorter regimes with slower initial rates of infusion have now been introduced with a reduced incidence of these adverse effects. In addition, there has been a move to use larger doses of N-acetylcysteine given over longer periods for patients who are more severely poisoned and those with risk factors. There has been much interest recently in the search for novel biomarkers such as microRNAs, procalcitonin and cyclophilin that promise to have greater specificity and sensitivity than transaminases. Paracetamol-protein adducts predict hepatotoxicity and are specific biomarkers of toxic paracetamol metabolite exposure. Another approach would be measurement of the plasma levels of cysteine and inorganic sulfate. It is 50 years since the first effective treatment for paracetamol poisoning and, apart from liver transplantation, there is still no effective treatment for patients who present late.

Fifty years of paracetamol (acetaminophen) poisoning: the development of risk assessment and treatment 1973-2023 with particular focus on contributions published from Edinburgh and Denver

INTRODUCTION

Fifty years ago, basic scientific studies and the availability of assay methods made the assessment of risk in paracetamol (acetaminophen) poisoning possible. The use of the antidote acetylcysteine linked to new methods of risk assessment transformed the treatment of this poisoning. This review will describe the way in which risk assessment and treatments have developed over the last 50 years and highlight the remaining areas of uncertainty.

METHODS

A search of PubMed and its subsidiary databases revealed 1,166 references published in the period 1963-2023 using the combined terms "paracetamol", "poisoning", and "acetylcysteine". Focused searches then identified 170 papers dealing with risk assessment of paracetamol poisoning, 141 with adverse reactions to acetylcysteine and 114 describing different acetylcysteine regimens. To manage the extensive literature, we focused mainly on contributions made by the authors during their time in Edinburgh and Denver.

DOSE AND CONCENTRATION RESPONSE

The key relationship between paracetamol dose and toxicity risk was established in 1971 and led to the development of the Rumack-Matthew nomogram from data collected in Edinburgh.

MECHANISMS OF TOXICITY

A series of papers on the mechanisms of toxicity were published in 1973, and these showed that paracetamol hepatotoxicity was caused by the formation of a toxic intermediate epoxide metabolite normally detoxified by glutathione but which, in excess, was bound covalently to hepatic enzymes and proteins. An understanding of the relationship between the rate of paracetamol metabolism, paracetamol concentration, and toxic hazard in humans soon followed.

ANTIDOTE DEVELOPMENT AND EFFICACY IN PATIENTS

These discoveries were followed by the testing of a range of sulfhydryl-donors in animals and "at risk" patients. Acetylcysteine was developed as the lead intravenous antidote in the United Kingdom. The license holder in the United States refused to make an intravenous formulation. Thus, oral acetylcysteine became the antidote trialed in the United States National Multicenter Study. Intravenous acetylcysteine regimens used initially in the United Kingdom and subsequently in the United States used loading doses of 150 mg/kg over 15 minutes or one hour, 50 mg/kg over four hours, and 100 mg/kg over 16 hours. These regimens were associated with adverse drug reactions (nausea, vomiting and anaphylactoid reactions) and hence, treatment interruption. Newer dosing regimens now give loading doses more slowly. One, the Scottish and Newcastle Anti-emetic Pretreatment protocol, using an acetylcysteine regimen of 100 mg/kg over two hours followed by 200 mg/kg over 10 hours, has been widely adopted in the United Kingdom. A cohort comparison study suggests this regimen has comparable efficacy to standard regimens and offers opportunities for selective higher acetylcysteine dosing.

RISK ASSESSMENT AT PRESENTATION

No dose-ranging studies with acetylcysteine were done, and no placebo-controlled studies were performed. Thus, there is uncertainty regarding the optimal dose of acetylcysteine, particularly in patients ingesting very large overdoses of paracetamol. The choice of intervention concentration on the Rumack-Matthew nomogram has important consequences for the proportion of patients treated. The United States National Multicenter Study used a "treatment" line starting at 150 mg/L (992 µmol/L) at 4 hours post overdose, extending to 24 hours with a half-life of 4 hours, now standard there, and subsequently adopted in Australia and New Zealand. In the United Kingdom, the treatment line was initially 200 mg/L (1,323 µmol/L) at 4 hours (the Rumack-Matthew "risk" line). In 2012, the United Kingdom Medicines and Healthcare products Regulatory Agency lowered the treatment line to 100 mg/L (662 µmol/L) at 4 hours for all patients, increasing the number of patients admitted and treated at a high cost. Risk assessment is a key issue for ongoing study, particularly following the development of potential new antidotes that may act in those at greatest risk. The development of biomarkers to assess risk is ongoing but has yet to reach clinical trials.

CONCLUSION

Even after 50 years, there are still areas of uncertainty. These include appropriate acetylcysteine doses in patients who ingest different paracetamol doses or multiple (staggered) ingestions, early identification of at-risk patients, and optimal treatment of late presenters.

A comprehensive review of Dynamic Chemical Labelling on Luminex xMAP technology: a journey towards Drug-Induced Liver Injury testing

Drug-Induced Liver Injury (DILI) is a grave global adverse event that can result in fatal consequences, causing drug failures, market withdrawals, and regulatory warnings, leading to substantial financial losses. The early detection of DILI remains a significant challenge in global healthcare. Although circulating microRNAs (miRs) show promise as clinical biomarkers for DILI, the current analytical methods for their measurement are insufficient. There is a pressing need for rapid and reliable miR detection methods that eliminate the need for nucleic acid extraction and PCR-based amplification. This review highlights recent advancements achieved by integrating Dynamic Chemical Labelling (DCL) with Luminex xMAP technology. This powerful combination has resulted in groundbreaking bead-based assays that allow (1) the direct, multiplex detection of miRs, and (2) the simultaneous testing of miR and protein biomarkers. This triple capability enables a comprehensive assessment that significantly enhances the detection and analysis of crucial biomarkers, thus improving the understanding and diagnosis of DILI. In conclusion, this review offers valuable insights into the capabilities and potential applications of these groundbreaking assays in DILI research, as well as their potential use in other diagnostic and research domains that require direct or multiplex analysis of miRs or analysis of miRs in combination with proteins.

Effective strategy to cope the pain and discomfort among women undergoing mammography - A randomized controlled trial

Objectives

To evaluate the role of paracetamol in reducing pain and discomfort during the mammography procedure.

Methods

This randomized double-blind placebo-controlled trial was conducted at DIR, Ojha and LEJ Campus of DUHS from November 2019 to May 2021. All females aged above 40 years undergoing first time mammogram (screening or diagnostic) were enrolled. Of 639 included participants, 321 were included in paracetamol and 318 in placebo group. Patients in both the groups took medication orally which was customized by the Dow Pharmacy. The degree of pain felt during the mammography procedure was the outcome variable that was measured using Visual Analogue Scale.

Results

The overall pain was found in 506 (79.19%) women. Pain was significantly higher in women who were in placebo group as compared to patients who were in paracetamol group, i.e., 280 (55.3%) and 226 (44.7%) (p-value <0.001). After adjustment of other covariates, the odds of pain was 3.64 times significantly higher in women who were in placebo group than that of women in paracetamol group (OR 3.64, 95% CI 2.31-5.74). Moreover, >25kg/m2 BMI was 2.84 times, 22.6-25 kg/m2 BMI was 2.29 times, nulligravida was 3.56 times, menopausal status was 2.23 times, pre-menopausal status was 4.51 times, and family history of breast cancer was 2.33 times significantly more likely to have pain. No post-trial complications were observed in both the groups.

Conclusion

The use of paracetamol prior to the mammography procedure was found to be an effective intervention to reduce the pain among women.Clinical Trials: Identifier: NCT04381104.

Paracetamol (acetaminophen) overdose and hepatotoxicity: mechanism, treatment, prevention measures, and estimates of burden of disease

INTRODUCTION

Paracetamol is one of the most used medicines worldwide and is the most common important poisoning in high-income countries. In overdose, paracetamol causes dose-dependent hepatotoxicity. Acetylcysteine is an effective antidote, however despite its use hepatotoxicity and many deaths still occur.

AREAS COVERED

This review summarizes paracetamol overdose and toxicity (including mechanisms, risk factors, risk assessment, and treatment). In addition, we summarize the epidemiology of paracetamol overdose worldwide. A literature search on PubMed for poisoning epidemiology and mortality from 1 January 2017 to 26 October 2022 was performed to estimate rates of paracetamol overdose, liver injury, and deaths worldwide.

EXPERT OPINION

Paracetamol is widely available and yet is substantially more toxic than other analgesics available without prescription. Where data were available, we estimate that paracetamol is involved in 6% of poisonings, 56% of severe acute liver injury and acute liver failure, and 7% of drug-induced liver injury. These estimates are limited by lack of available data from many countries, particularly in Asia, South America, and Africa. Harm reduction from paracetamol is possible through better identification of high-risk overdoses, and better treatment regimens. Large overdoses and those involving modified-release paracetamol are high-risk and can be targeted through legislative change.

Toxicology in the emergency department: what's new?

Intentional and accidental drug overdose, recreational drug use and exposure to toxic substances are common reasons for people presenting to emergency departments. Although the mortality rate associated with these presentations is low in the UK, they can lead to significant morbidity and prolonged hospital admissions.

This review discusses new developments in the management of paracetamol overdose. Several new protocols for the infusion of acetylcysteine, the antidote for paracetamol overdose, have been proposed in the past decade and evaluated in clinical studies. The 12-hour Scottish and Newcastle Acetylcysteine Protocol regimen and 20-hour Australian two-infusion bag protocol have been widely adopted into clinical practice and endorsed in national guidelines because of their shorter duration, reduction in adverse effects and efficacy in treating overdose. This article includes a care pathway that can facilitate the implementation of the Scottish and Newcastle Acetylcysteine Protocol.

This article also discusses the emergency management of ingested button batteries, describes the emerging threat of novel psychoactive substances, and provides an update on new UK antidote guidelines. Further up-to-date guidance on management of clinical toxicology is available to healthcare professionals on the internet database TOXBASE.

Has the time come to stop routine N-acetylcysteine treatment in young children in Denmark? A review of 300 suspected paracetamol overdoses in children aged 0-6 years

AIM

To evaluate the prevalence of potentially hepatoxic paracetamol ingestion and associated N-acetylcysteine treatment in young children suspected of paracetamol poisoning.

METHODS

A retrospective cohort study of children aged 0-6 years suspected of paracetamol poisoning with a related plasma-paracetamol measurement in the Capital Region of Denmark in the period 2010-2017. Data from the clinical laboratory system were linked to data from electronic patient records via the unique identification number given to all Danish residents.

RESULTS

Of 297 children included, suspected single paracetamol overdoses were present in 281 (95%). Sixty-nine per cent were treated with N-acetylcysteine, and the mean treatment period was 20.3 h (SD 20.8). A maximum of 6 (2%) of the children suspected of single overdose had plasma-paracetamol concentrations that exceeded the recommended treatment thresholds. No cases of severe hepatotoxicity were registered. Adverse events to N-acetylcysteine-treatment were registered in 3 (2%) children including one anaphylactoid reaction (0.5%).

CONCLUSION

This study shows that initiating N-acetylcysteine as a 'one size fit all' treatment regimen in all children aged 0-6 years with a suspected single paracetamol overdose leads to substantial overtreatment. The data support that it is feasible to initiate N-acetylcysteine within 10 h based on an early plasma-paracetamol test.

Sensitivity of dose-estimations for acute acetaminophen overdose in predicting hepatotoxicity risk using the Rumack-Matthew Nomogram

Timely assessment of acetaminophen concentration in overdose situations is not always available in resource-poor settings. The 150 mg/kg dose-estimate for acetaminophen is widely considered as criterion for acetaminophen overdose. Its sensitivity and specificity when compared to the 150 mg/L treatment line on the Rumack-Matthew Nomogram (150-treatment line) has rarely been evaluated. This is a retrospective chart review of acute acetaminophen overdose patients. We evaluated the sensitivity and specificity of the 150, 200 mg/kg and 8- and 10-g dose-estimates by plotting the serum acetaminophen levels and using 150-treatment line on the Nomogram as the treatment cut-off. A comparison of medical care costs was performed. We enrolled 784 cases for analysis. Median (IQR) age was 23 (20-28) years (81.9% female). There were 545 cases (69.5%) where the estimated ingested acetaminophen dose were ≥150 mg/kg and 406 cases (51.8%) with concentrations ≥150-treatment line. Hepatotoxicity and acute liver injury (ALI) occurred in 7.3% and 23.9%, respectively. The sensitivity and specificity of 150 mg/kg dose-estimate for the 150-treatment line were 92.6% (95% CI 89.6, 94.8) and 55.3% (95% CI 50.3, 60.2). Among patients with dose-estimate below150 mg/kg, none developed hepatotoxicity and 17 (7.1%) develop ALI. The administration of activated charcoal significantly decreased the risk of being above the 150-treatment line by half. In resource-poor setings, the use of 150 mg/kg dose-estimate as a stand-alone criteria for initiation of N-acetylcysteine therapy is satisfactory, especially when combined with decontamination with activated charcoal and follow up of aminotransferase at 24 h.

Evaluation of cut-off values in acute paracetamol overdose following the United Kingdom guidelines

Background

The United Kingdom guideline for acute paracetamol overdose has recommended the use of ‘100-treatment line’. Emergency medical centers in some developing countries lack the resources for timely reporting of paracetamol concentrations, hence treatment depends on reported dose. This study aimed to examine whether using an reported dose is safe to predict concentration above the 100-line.

Methods

Data were retrieved from two emergency medical centers retrospectively, between 2010 and 2017. The inclusion criteria were single acute paracetamol overdose, presentation within 15 h, and age ≥ 14 years. Multiple linear regression was performed to determine the effect of ingested dose on paracetamol concentration. Subgroups were created based on ingested dose, rate of concentration above 100-line were investigated.

Results

One hundred and seventy-two patients were enrolled in the primary analysis; median dose was 133.3 mg/kg and 46 (37.8%) had concentration above 100-line in the first test. Only dose per weight was moderately correlated with the first concentration (R² = 0.410, p < 0.001). In the ≤200 mg/kg ingestion group, 18 patients showed concentration above 100-line and 8 showed acute liver injury. The cut-off value of 150 mg/kg showed 82.6% sensitivity and 73.8% specificity to predict concentration above 100-line.

Conclusion

Where paracetamol concentration is not available and activated charcoal is readily used, following United Kingdom guideline, it is safe to use an ingested dose of > 150 mg/kg as the cut-off value for N-acetylcysteine treatment with risk stratification for hepatotoxicity if the patient is ≥14 years and visit the ED within 15 h after an acute paracetamol overdose.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-021-00547-1.

Detection of paracetamol binding to albumin in blood serum using 2D-IR spectroscopy

Two-Dimensional Infrared (2D-IR) spectroscopy is used to detect binding of paracetamol with proteins in blood serum. Quantitative peak patterns are observed indicating structural changes of the albumins' secondary structure when paracetamol bound.

Fifteen-minute update: International normalised ratio as the treatment end point in children with acute paracetamol poisoning

Paracetamol is one of the most frequent reasons for poisonings across the UK with an estimated 90,000 patients and 150 deaths annually. International normalised ratio (INR) may be elevated due to hepatocellular damage and is frequently used to monitor progress on N-acetyl cysteine. N-acetyl cysteine is associated with reduced activity of vitamin K dependent clotting factors leading to a benign elevation of INR. In asymptomatic children with normal aspartate transaminase/alanine transaminase, isolated borderline elevation of INR following paracetamol overdose should be reviewed for possible N-acetyl cysteine induced elevation of INR. Due to these factors, in those with borderline persistent elevation of INR, N-acetyl cysteine can be safety stopped if INR is falling on two or more consecutive tests and is <3.0.

Plasma Concentration of Taurine Changes following Acetaminophen Overdose in Male Patients during Hospitalization

Changes in plasma concentration of taurine during hospitalization of acetaminophen poisoned patients have not been studied. Hepatotoxicity is a common consequence of acetaminophen overdose that may lead to acute liver failure. Numerous biomarkers for drug-induced liver injury have been explored. All biomarkers are usually obtainable 48 h following acetaminophen overdose. We have already introduced taurine as a non-specific early biomarker of acetaminophen overdose. This study aimed to follow up changes in plasma concentration of taurine during the first three days of acetaminophen overdose. Sixty-four male patients suffering from acetaminophen overdose were selected for the study. Four blood samples were taken from the patients every 12 h. Sixty blood samples were also taken from sixty healthy humans. The plasma concentration of taurine in both groups was analyzed an already developed HPLC method. Analysis of regression showed a significant correlation between means of plasma concentrations of taurine and acetaminophen, aspartate aminotransferase, Alanine aminotransferase, glutathione peroxidase, and prothrombin time during hospitalization. The high plasma concentration of taurine, 6 h or more after acetaminophen overdose, could be a useful early indicator of liver damage.

Plasma procalcitonin may be an early predictor of liver injury in acetaminophen poisoning: A prospective cohort study

Background and Aims

Acetaminophen is a common cause of poisoning and liver injury worldwide; however, patient stratification is suboptimal. We aimed to assess the contribution of admission plasma procalcitonin concentration (PCT) to better identify acetaminophen‐poisoned patients likely to develop liver injury.

Methods

We conducted a prospective observational cohort study including all acetaminophen‐poisoned patients requiring N‐acetylcysteine admitted in a toxicological intensive care unit between 2012 and 2017. Multivariate analysis was performed using a Cox regression model to investigate factors associated with liver injury, defined as an increase in alanine aminotransferase (ALT) >100 IU/L.

Results

One hundred seventeen patients (age, 32 years (21–53), median [25th–75th percentiles]) were included after self‐ingesting 16 g (9–30) acetaminophen and received N‐acetylcysteine infusion administered within a median 6 h‐delay (4–12) from exposure. Co‐ingestions were reported in 77% of patients. Rumack–Matthew nomogram was non‐interpretable in 47% cases. Liver injury occurred in 38 patients (32%) with a median peak ALT of 2020 IU/L (577–4248). In liver injury patients, admission PCT was significantly increased in comparison to patients without liver injury (21.5 ng/ml (3.2–44.9) versus 0.1 ng/ml (0–0.4), respectively, p < 0.01). The increase in PCT preceded the increase in ALT by 33 h (10–74). In a multivariate analysis, PCT > 1 ng/ml was significantly associated with liver injury (hazard ratio, 7.2 [95% confidence interval, 2.3–22.6; p < 0.001]). PCT (area under the receiver‐operating characteristics curve, 0.91 [95%CI: 0.84–0.97]) predicted liver injury with sensitivity, specificity, negative, and positive predictive values of 0.92, 0.84, 0.96, and 0.73, respectively.

Conclusion

PCT on admission is associated with liver injury in acetaminophen poisoning. PCT might be used as a predictive tool of liver injury to improve clinical decision‐making.

Management of pharmaceutical and recreational drug poisoning

BACKGROUND

Poisoning is one of the leading causes of admission to the emergency department and intensive care unit. A large number of epidemiological changes have occurred over the last years such as the exponential growth of new synthetic psychoactive substances. Major progress has also been made in analytical screening and assays, enabling the clinicians to rapidly obtain a definite diagnosis.

METHODS

A committee composed of 30 experts from five scientific societies, the Société de Réanimation de Langue Française (SRLF), the Société Française de Médecine d'Urgence (SFMU), the Société de Toxicologie Clinique (STC), the Société Française de Toxicologie Analytique (SFTA) and the Groupe Francophone de Réanimation et d'Urgences Pédiatriques (GFRUP) evaluated eight fields: (1) severity assessment and initial triage; (2) diagnostic approach and role of toxicological analyses; (3) supportive care; (4) decontamination; (5) elimination enhancement; (6) place of antidotes; (7) specificities related to recreational drug poisoning; and (8) characteristics of cardiotoxicant poisoning. Population, Intervention, Comparison, and Outcome (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. Analysis of the literature and formulation of recommendations were then conducted according to the GRADE® methodology.

RESULTS

The SRLF-SFMU guideline panel provided 41 statements concerning the management of pharmaceutical and recreational drug poisoning. Ethanol and chemical poisoning were excluded from the scope of these recommendations. After two rounds of discussion and various amendments, a strong consensus was reached for all recommendations. Six of these recommendations had a high level of evidence (GRADE 1±) and six had a low level of evidence (GRADE 2±). Twenty-nine recommendations were in the form of expert opinion recommendations due to the low evidences in the literature.

CONCLUSIONS

The experts reached a substantial consensus for several strong recommendations for optimal management of pharmaceutical and recreational drug poisoning, mainly regarding the conditions and effectiveness of naloxone and N-acetylcystein as antidotes to treat opioid and acetaminophen poisoning, respectively.

Amplification-free profiling of microRNA-122 biomarker in DILI patient serums, using the luminex MAGPIX system

Dynamic chemical labelling is a single-base specific method to enable detection and quantification of micro-Ribonucleic Acids in biological fluids without extraction and pre-amplification. In this study, dynamic chemical labelling was combined with the Luminex MAGPIX system to profile levels of microRNA-122 biomarker in serum from patients with Drug-Induced Liver Injury.

Liver injury induced by paracetamol and challenges associated with intentional and unintentional use

Drug induced liver injury (DILI) is a common cause of acute liver injury. Paracetamol, also known as acetaminophen, is a widely used anti-pyretic that has long been established to cause liver toxicity once above therapeutic levels. Hepatotoxicity from paracetamol overdose, whether intentional or non-intentional, is the most common cause of DILI in the United States and remains a global issue. Given the increased prevalence of combination medications in the form of pain relievers and antihistamines, paracetamol can be difficult to identify and remains a significant cause of acute hepatotoxicity, as evidenced by its contribution to over half of all acute liver failure cases in the United States. This is especially concerning given that, when co-ingested with other medications, the rise in serum paracetamol levels may be delayed past the 4-hour post-ingestion mark that is currently used to determine patients that require medical therapy. This review serves to describe the clinical and pathophysiologic features of hepatotoxicity secondary to paracetamol and provide an update on current available knowledge and treatment options.

An Appraisal of Antidotes' Effectiveness: Evidence of the Use of Phyto-Antidotes and Biotechnological Advancements

Poisoning is the greatest source of avoidable death in the world and can result from industrial exhausts, incessant bush burning, drug overdose, accidental toxication or snake envenomation. Since the advent of Albert Calmette’s cobra venom antidote, efforts have been geared towards antidotes development for various poisons to date. While there are resources and facilities to tackle poisoning in urban areas, rural areas and developing countries are challenged with poisoning management due to either the absence of or inadequate facilities and this has paved the way for phyto-antidotes, some of which have been scientifically validated. This review presents the scope of antidotes’ effectiveness in different experimental models and biotechnological advancements in antidote research for future applications. While pockets of evidence of the effectiveness of antidotes exist in vitro and in vivo with ample biotechnological developments, the utilization of analytic assays on existing and newly developed antidotes that have surpassed the proof of concept stage, as well as the inclusion of antidote’s short and long-term risk assessment report, will help in providing the required scientific evidence(s) prior to regulatory authorities’ approval.

Incidence and general hospital costs of self-harm across England: estimates based on the multicentre study of self-harm

AIMS

The aim of this study was to estimate incidence of self-harm presentations to hospitals and their associated hospital costs across England.

METHODS

We used individual patient data from the Multicentre Study of Self-harm in England of all self-harm presentations to the emergency departments of five general hospitals in Oxford, Manchester and Derby in 2013. We also obtained cost data for each self-harm presentation from the hospitals in Oxford and Derby, as well as population and geographical estimates from the Office for National Statistics. First, we estimated the rate of self-harm presentations by age and gender in the Multicentre Study and multiplied this with the respective populations to estimate the number of self-harm presentations by age and gender for each local Clinical Commissioning Group (CCG) area in England. Second, we performed a regression analysis on the cost data from Oxford and Derby to predict the hospital costs of self-harm in Manchester by age, gender, receipt of psychosocial assessment, hospital admission and type of self-harm. Third, the mean hospital cost per age year and gender were combined with the respective number of self-harm presentations to estimate the total hospital costs for each CCG in England. Sensitivity analysis was performed to address uncertainty in the results due to the extrapolation of self-harm incidence and cost from the Multicentre Study to England.

RESULTS

There were 228 075 estimated self-harm presentations (61% were female) by 159 857 patients in 2013 in England. The largest proportions of self-harm presentations were in the age group 40-49 years (30%) for men and 19-29 years (28%) for women. Associated hospital costs were approximately £128.6 (95% CI 117.8-140.9) million in 2013. The estimated incidence of self-harm and associated hospital costs were lower in the majority of English coastal areas compared to inland regions but the highest costs were in Greater London. Costs were also higher in more socio-economically deprived areas of the country compared with areas that are more affluent. The sensitivity analyses provided similar results.

CONCLUSIONS

The results of this study highlight the extent, hospital costs and distribution of self-harm presentations to hospitals in England and identify potential sub-populations that might benefit from targeted actions to help prevent self-harm and assist those who have self-harmed. They can support national as well as local health stakeholders in allocating funds and prioritising interventions in areas with the greatest need for preventing and managing self-harm.

Efficacy of a two bag acetylcysteine regimen to treat paracetamol overdose (2NAC study)

BACKGROUND

Previous studies of paracetamol overdose treatment show that a 2-bag, 20-h intravenous (IV) acetylcysteine regimen decreased the incidence of non-allergic anaphylactic reactions compared to the 3-bag, 21 h IV regimen, but have not examined efficacy of the 20-h 2 bag regimen.

METHODS

This was a multi-centre observational study of paracetamol overdose presentations treated with a 2-bag IV acetylcysteine regimen (200 mg/kg over 4 h, 100 mg/kg over 16 h) compared to a 3-bag regimen, performed from 2009 to 2019. Patients were referred from the emergency department to the inpatient toxicology units for continued management. For the primary non-inferiority analysis: subjects had single, acute ingestions, a serum paracetamol-concentration performed 4 to 8-h post-ingestion. The primary outcome was development of acute liver injury (ALI), defined as peak ALT>150 U/L; and > double admission baseline ALT (for presentations within 24 h post-overdose). Secondary outcomes included adverse reactions to acetylcysteine (cutaneous and systemic).

FINDING

Out of 6419 paracetamol overdoses, 2763 received acetylcysteine. For the primary analysis, 1003 received the 2-bag and 783 the 3-bag acetylcysteine regimen. When presentation bloods were performed 4 to 8-h post-overdose, 21 (3.1%) developed ALI with the 2-bag regimen vs 16 (2.9%) with the 3-bag regimen (Difference: 0.2%, 95%CI:-1.6 to 2.2). The incidence of hepatotoxicity was: 1.2% (n = 8) with the two-bag regimen and 1.6% (n = 9) with the three-bag regimen (Difference -0.4%, 95%CI -1.75, 0.91). When presentation bloods were performed 8 to 24-h post-overdose, 70 (21%) developed ALI with the 2-bag regimen vs 46 (23%) with the 3-bag regimen (Difference: -2%, 95%CI -9.12 to 5.36). There were significantly less cutaneous and systemic non-allergic anaphylactic reactions recorded after treatment with the two-bag than the three-bag regimen (1.3% [n = 17] and 7.1% [n = 65], Difference: -5.8%, 95%CI -7.6 to -4.0, p < 0.0001), respectively.

INTERPRETATION

A two-bag intravenous acetylcysteine regimen was found to be non-inferior to the three-bag regimen with regards to efficacy in preventing acute liver injury for early presentations of paracetamol overdose. No important differences were seen for any other presentations. The two-bag regimen also decreased the incidence of both non-allergic anaphylactic reactions and gastrointestinal adverse events from acetylcysteine treatment.

FUNDING

AW is funded by a National Health and Medical Research Council (NHMRC) Early Career Fellowship ID 1159907. GI is funded by a NHMRC Senior Research Fellowship ID 1061041. The NHMRC had no role in the design, writing of this manuscript. The corresponding author (AW) had full access to all the data in the study and final responsibility for the decision to submit the manuscript for publication.

Exploring characteristics and risk of repetition in people who fail to report previous hospital presentations for self-harm: A case-control study using data from The Manchester Self-Harm Project

BACKGROUND

As a risk factor for future self-harm and suicide, questions about past self-harm are typically included in assessments that help inform management of people who self-harm. However, little is known about people with a history of self-harm who do not report it. This study aimed to describe and compare (i) characteristics of people who did or did not accurately report previous self-harm, and (ii) 12-month repetition of self-harm.

METHODS

Data on all self-harm presentations to three hospital emergency departments in England were collected from 2003 to 2015. A 1:5 matched case-control design included 374 cases where previous self-harm was not reported and 1,870 controls where previous self-harm was reported. Data were analysed using conditional logistic regression and survival analysis.

RESULTS

Cases were more likely to be male (OR 1.42; 95% CI 1.13-1.77), middle-aged (OR 1.41; 95% CI 1.08-1.83), employed (OR 1.51; 95% CI 1.15-1.98), and less likely be referred to psychiatric services (OR 0.53; 95% CI 0.35-0.80). Twelve-month repetition was similar in cases and controls (30% vs 31%).

LIMITATIONS

Self-harm not resulting in a hospital presentation could not be verified and individuals with a single episode in the study database were therefore excluded.

CONCLUSIONS

Previous self-harm is an important risk factor for repetition in people who accurately recall and report it and those who fail to report it. Those who do not report previous self-harm are less likely to be referred to psychiatric services, emphasising the need for careful assessment of every self-harm presentation to emergency departments.

Direct Detection of miR-122 in Hepatotoxicity Using Dynamic Chemical Labeling Overcomes Stability and isomiR Challenges

Circulating microRNAs are biomarkers reported to be stable and translational across species. MicroRNA-122 (miR-122) is a hepatocyte-specific microRNA biomarker for drug-induced liver injury (DILI). We developed a single molecule, dynamic chemical labeling (DCL) assay to directly detect miR-122 in blood. The DCL assay specifically measured miR-122 directly from 10 μL of serum or plasma without any extraction steps, with a limit of detection of 1.32 pM that enabled the identification of DILI. Testing of 192 human serum samples showed that DCL accurately identified patients at risk of DILI after acetaminophen overdose (area under ROC curve 0.98 (95% CI; 0.96-1), P < 0.0001). The DCL assay also identified liver injury in rats and dogs. The use of specific captured beads had the additional benefit of stabilizing miR-122 after sample collection, with no signal loss after 14 days at room temperature, in contrast to PCR that showed significant loss of signal. RNA sequencing demonstrated the presence of multiple miR-122 isomiRs in the serum of patients with DILI that were at low concentration or not present in healthy individuals. Sample degradation over time produced more isomiRs, particularly rapidly with DILI. PCR was inaccurate when analyzing miR-122 isomiRs, whereas the DCL assay demonstrated accurate quantification. We conclude that the DCL assay can accurately measure miR-122 to diagnose liver injury in humans and other species and can overcome microRNA stability and isomiR challenges.

Impact of medicines regulatory risk communications in the UK on prescribing and clinical outcomes: Systematic review, time series analysis and meta-analysis

AIMS

Regulatory risk communications are important to ensure medication safety, but their impact is poorly understood. The aim was to quantify the impact of UK risk communications on medication use and other outcomes.

METHODS

We conducted a systematic review of studies reporting prescribing/health outcome data relevant to UK regulatory risk communication. Data were reanalysed using interrupted time series regression 12 months after each regulatory intervention. Mean changes were pooled using random-effects generic inverse variance examining the following subgroups: drug withdrawals; restrictions/changes in indications; be aware messages without specific recommendations for action; communication via direct healthcare practitioner communications; communication via drug bulletins.

RESULTS

Of 11 466 articles screened, 40 studies examining 25 UK regulatory risk communications were included. Product withdrawals, restriction in indications and be aware communications were associated with relative mean changes of -78% (95% confidence interval [CI] -60 to -96%), -34% (95% confidence interval [CI] -12 to -55%) and -11% (95%CI -8 to -15%) in targeted drug prescribing respectively. Direct healthcare professional communications were associated with relative mean changes of -47% (95%CI -27 to -68%) compared to -13% (95%CI -6 to -20%) for drug bulletins. Of 7 studies examining unique health outcomes related to the safety concern, risk communications were associated with a mean -10% (95%CI -3 to -16%) decrease in intended and a 7% (95%CI 4 to 10%) increase in unintended health outcomes.

DISCUSSION

UK regulatory risk communications were associated with significant changes in targeted prescribing and potential changes in clinical outcomes. Further research is needed to systematically study the impact of regulatory interventions.

Reply to the ‘Comment on “Acetylcysteine in paracetamol poisoning: a perspective of 45 years of use”’ by M. E. Mullins, M. C. Yarema, M. L. A. Sivilotti, M. Thompson, D. A. Algren, M. C. Beuhler and C. P. Holstege, Toxicol. Res., 2019, 8, DOI: 10.1039/C9TX00158A

Mullins et al. made a comment on our article (DOI: ; 10.1039/C9TX00002J) stating they noticed the omission of the one-bag, standard concentration protocol which is shared by several centers in North America when we discussed IV acetylcysteine protocols. In this reply we clarify that we did not include this methodology as it is a technical adaption of the way in which a 2-bag NAC regimen in administered and there is insufficient comparative data with other regimens.

Adults with acute poisoning admitted to a university hospital in Belgium in 2017: cost analysis benchmarked with national data

Objective: Aims were to (1) analyse the direct cost charged by a university hospital to the government and the patient in case of an admission for acute poisoning, (2) identify the factors associated with the cost, and (3) compare the cost in the hospital studied with national data from the government.Methods: Patient records and invoices of all poisoning-related episodes of patients 14 years or older admitted to the Emergency Department (ED) of Ghent University Hospital (GUH) in 2017 were analysed. A generalised linear model with gamma loglink was applied to assess the variables associated with the cost. Our GUH data collected in 2017 were compared with national data 2016 for all Belgian hospitals on the one hand, and for the subgroup of GUH 2016 data on the other hand. To do this, we used data provided by the Technical Unit of the Federal Public Service Health, containing All Patient Refined Diagnosis Related Groups 812 (poisoning by medicinal agents) and 816 (toxic effects by non-medicinal substances).Results: The total direct cost for the treatment of 1,175 poisoned patients amounted to $1,830,870. Median direct cost per patient was $512 per episode, with $199 for ambulatory patients, $1,575 for patients admitted to the ED-observation-unit, $3,398 for hospitalised patients and $4,859 for patients treated in the intensive care unit. Factors associated with the cost were gender, degree of severity, type of hospitalisation, intentionality, and involvement of ethanol, paracetamol, antidepressants or amphetamines. Median hospitalisation cost per admission in GUH for medicinal agents was 70.5% higher than the cost reported in national hospitalisation data. Median cost per admission in case of non-medicinal agents was 54.5% higher than the national median 2016.Conclusion: The type of hospitalisation has a high impact on the cost, a.o. primarily due to the length of hospital stay, with accommodation accounting for a large proportion of the costs. It is important to benchmark individual hospital data with (inter)national data to evaluate its own cost management in the context of continuous improvement.

Acetylcysteine in paracetamol poisoning: a perspective of 45 years of use

Paracetamol poisoning was first reported in 1966. The development of antidotes followed within 10 years, and by 1980 acetylcysteine (NAC) was acknowledged as the optimal therapy available. This article examines the history of the development of NAC and recent developments in its use. We offer suggestions for improvements in the way NAC may be administered and outline new developments that should have major impacts on the way we manage paracetamol poisoning in the near future.

SIRT1 Modulators in Experimentally Induced Liver Injury

This article is directed at highlighting the involvement of the endogenous stress sensor SIRT1 (silent information regulator T1) as a possible factor involved in hepatoprotection. The selective SIRT1 modulators whether activators (STACs) or inhibitors are being tried experimentally and clinically. We discuss the modulation of SIRT1 on cytoprotection or even cytotoxicity in the liver chemically injured by hepatotoxic agents in rats, to shed light on the crosstalk between SIRT1 and its modulators. A combination of D-galactosamine and lipopolysaccharide (D-GalN/LPS) downregulated SIRT1 expression, while SIRT1 activators, SRT1720, resveratrol, and quercetin, upregulated SIRT1 and alleviated D-GalN/LPS-induced acute hepatotoxicity. Liver injury markers exhibited an inverse relationship with SIRT1 expression. However, under subchronic hepatotoxicity, quercetin decreased the significant increase in SIRT1 expression to lower levels which are still higher than normal ones and mitigated the liver-damaging effects of carbon tetrachloride. Each of these STACs was hepatoprotective and returned the conventional antioxidant enzymes to the baseline. Polyphenols tend to fine-tune SIRT1 expression towards normal in the liver of intoxicated rats in both acute and subchronic studies. Together, all these events give an impression that the cytoprotective effects of SIRT1 are exhibited within a definite range of expression. The catalytic activity of SIRT1 is important in the hepatoprotective effects of polyphenols where SIRT1 inhibitors block and the allosteric SIRT1 activators mimic the hepatoprotective effects of polyphenols. Our findings indicate that the pharmacologic modulation of SIRT1 could represent both an important move in alleviating hepatic insults and a future major step in the treatment of xenobiotic-induced hepatotoxicity.

MicroRNA from a 12-h versus 20-h acetylcysteine infusion for paracetamol overdose

Paracetamol overdose is common and microRNA (miR)-122 expression is increased with liver injury. We aimed to measure miR-122 in the setting of an abbreviated paracetamol overdose treatment regimen. We compared miRNA expression in patients treated for paracetamol poisoning with an abbreviated 12-h intravenous acetylcysteine regimen (200 mg/kg over 4 h, 50 mg/kg over 8 h) or a 20-h regimen (200 mg/kg over 4 h, 100 mg/kg over 16 h) (NACSTOP trial). miR-122 expression is increased (decreased cycle threshold (Ct) values) with paracetamol liver injury. We assessed miR-122 expression in patients receiving the two acetylcysteine regimens and in a separate group with acute liver injury (ALI). We examined 121 blood samples in 38 patients. After 20 h of acetylcysteine, median alanine transaminase (ALT) was 12 U/L (18, 14) versus 16 U/L (11, 21) ( p = 0.17) and median miR-122 Ct was 30.1 (interquartile range (IQR): 28.9, 33.3) versus 31.4 (28.9, 33.9) ( p = 0.7) in the NACSTOP abbreviated and control groups, respectively. Median normalized miR-122 Ct after 20 h of acetylcysteine was 2.2 (IQR 1.9, 6.4), 1.1 (0.7, 2.9), 63.9 (2.5, 168), 123.2 (40.9, 207.8) in the NACSTOP-abbreviated, NACSTOP-control, ALI and hepatotoxicity groups, respectively. There was no significant difference in ALT or miRNA between NACSTOP treatment groups and no signal of increased liver injury from an abbreviated 12-h acetylcysteine regimen. These findings suggest that an abbreviated acetylcysteine regimen in low-risk patients who have overdosed on paracetamol is safe. Further study is required to validate this finding utilizing miRNA as a comparative biomarker.

Effect of chrysin on the formation of N-acetyl-p-benzoquinoneimine, a toxic metabolite of paracetamol in rats and isolated rat hepatocytes

Paracetamol (N-acetyl-para amino phenol) is the most commonly used analgesic and antipyretic around the world. Its causes hepatotoxicity and nephrotoxicity at overdose or even at therapeutic doses. It is primarily metabolized by glucuronidation and sulfate conjugation. It is also metabolized by cytochrome-P450 system (CYP2E1, CYP1A2 and CYP 3A4), leading to the formation of N-acetyl-p-benzoquinoneimine (NAPQI). The present study was planned to investigate the influence of chrysin (known CYP2E1 and CYP3A4 inhibitor) on the bioactivation of paracetamol to NAPQI using rat liver microsomes in vitro and rats in vivo. Paracetamol (80 mg/kg) was administered orally without or with silymarin (100 mg/kg), a known CYP2E1 inhibitor and chrysin (100 and 200 mg/kg) to rats for 15 consecutive days. The area under the plasma concentration-time curve (AUC_0-∞) and the peak plasma concentration (C_max) of paracetamol were dose-dependently increased with chrysin (100 and 200 mg/kg) compared to paracetamol control group. On the other hand, the AUC_0-∞ and C_max of NAPQI were decreased significantly with chrysin (100 and 200 mg/kg). The elevated liver and kidney function markers were significantly reduced by chrysin and silymarin compared to paracetamol control group (P < 0.01). Histopathological studies of liver and kidney also well correlated with liver and kidney function tests. Chrysin also reduced the formation of NAPQI in the incubation samples of rat hepatocytes. The present study (both in vivo and in vitro) results revealed that chrysin might be inhibited the CYP2E1, CYP1A2 and CYP3A4-mediated metabolism of paracetamol; thereby decreased the formation of NAPQI and protected the liver and kidney.

Acetaminophen aggravates fat accumulation in NAFLD by inhibiting autophagy via the AMPK/mTOR pathway

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease which affects millions of people worldwide. Acetaminophen (APAP) overdose is the leading cause of acute liver failure. In this study, APAP (50, 100, 200 mg/kg) were employed on mice fed with a high-fat diet, and APAP (2, 4, 8 mM) were cultured with L02 cells in the presence of alcohol and oleic acid. APAP treatment significantly aggravated hepatic lipid accumulation, increased the serum levels of triglyceride (TG), alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and increased hepatic lipid accumulation in H&E and Oil red O staining results. Transmission electron microscopy (TEM) found fewer number of autophagosomes in APAP (100 mg/kg) treated group. Immunohistochemistry analysis showed the intensity of hepatic mTOR was increased and AMPK was decreased in 200 mg/kg APAP treated group. Western blot analysis showed APAP treatment decreased the levels of LC3-Ⅱ, Beclin1 and AMPK, while increased the levels of mTOR and SREBP-1c, respectively. In vitro study showed APAP treatment obviously increased TG activities in cell supernatant, and Oil red O staining had the same results. Western blot analysis demonstrated APAP treatment decreased the levels of LC3-Ⅱ, Beclin1 and AMPK, increased the levels of mTOR and SREBP-1c, but rapamycin treatment significantly reversed these effects of APAP. In conclusion, therapeutic dosages of APAP aggravates fat accumulation in NAFLD, the potential mechanism might be involved in inhibiting autophagy associated with the AMPK/mTOR pathway, and patients with NAFLD should use a lower dose of APAP.

Central nervous system-active drug abused and overdose in children: a worldwide exploratory study using the WHO pharmacovigilance database

Recent epidemiological studies have reported an increase in central nervous system (CNS)-active drug abuse rates in paediatric settings, raising several public health concerns. No study to date has explored this issue worldwide. We performed an extensive analysis of drugs abuse/overdose reported for children in the last decade by using the largest pharmacovigilance database, i.e. the VigiBase, collecting adverse drug reaction reports that involved at least one suspect drug belonging to the Anatomical Therapeutic Chemical code "Nervous System" through the Standardised Medical Dictionary for Drug Regulatory Affairs Queries for Drug abuse. 8.682 reports matched our criteria. An increase in reporting activity was observed, starting from 2014; an intentional overdose was reported more frequently than an accidental one, with a difference between age groups. We retrieved 997 reports with death outcome. These referred more to adolescents (n = 538) than subjects of any other paediatric age group. Paracetamol and opioid analgesics were the most common suspect drugs in deaths across all age groups due to hypoxic-ischaemic encephalopathy, brain death, and cardio-respiratory arrest.Conclusion: The number of reports associated with drug abuse and overdose is increasing (for opioid and paracetamol-containing products) and a considerable number of adverse drug reactions are serious. Data on the patterns of use of such medicines from each country may help in implementing strategies of risk-minimisation and renewing healthcare recommendations worldwide. An increased clinical awareness of drug abuse and overdose is warranted, while continuing to provide effective treatments. What is Known: • The large increase in paediatric prescriptions for CNS-active drugs in the last 20 years has recently raised public health concerns about drug abuse and overdose. • No study to date has examined this issue in paediatric patients worldwide. What is New: • The number of paediatric reports associated with CNS drug abuse and intentional overdose is increasing, including those with fatal outcome; over 4 years; more than 35% of the reports was entered from European countries. • Opioid and paracetamol were most frequently suspected for ADRs with fatal outcome across all age groups, due to hypoxic-ischaemic encephalopathy and cardio-respiratory arrest, suggesting the need to implement strategies of risk-minimisation.

Paracetamol metabolite concentrations following low risk overdose treated with an abbreviated 12-h versus 20-h acetylcysteine infusion

CONTEXT

To compare degree of liver injury and paracetamol metabolite concentrations after treatment with standard of care (20-h) vs. abbreviated (12-h) acetylcysteine regimens used in paracetamol overdose (NACSTOP trial).

METHODS

Timed blood samples from a cohort of subjects enrolled in the cluster-controlled NACSTOP trial evaluating a 12-h acetylcysteine regimen (200 mg/kg over 4 h, 50 mg/kg over 8 h) were assayed for paracetamol metabolites as a pilot study, using liquid chromatography/mass spectrometry. Control group subjects received a 20-h course of acetylcysteine (200 mg/kg over 4 h, 100 mg/kg over 16 h). The intervention group received a 12-h acetylcysteine regimen (stopped after at least 12 h of treatment). Positive control groups not in the trial with acute liver injury (ALI) or hepatotoxicity were also studied.

RESULTS

One hundred and forty-one blood samples were collected from 40 patients receiving acetylcysteine after paracetamol overdose. Median ALT after 20 h of acetylcysteine was 12 U/L (IQR 8.14) in the abbreviated regimen group, compared to the control group 16 U/L (IQR 11.21) (p = .46). There was no significant difference in median metabolite concentrations on presentation and after 20 h of acetylcysteine between these two groups (p > .05). Presentation median sum CYP-metabolite/total metabolite percentages were 2.5 and 3.0 in the abbreviated and control NACSTOP groups, respectively.

CONCLUSIONS

An abbreviated 12-h acetylcysteine regimen for paracetamol overdose used in the NACSTOP trial had similar circulating metabolite concentrations compared to a 20-h regimen in selected subjects with low risk of hepatotoxicity. This suggests that further acetylcysteine may not be needed in the abbreviated group at time of cessation.

Systems Toxicology Approach to Identifying Paracetamol Overdose

Paracetamol (acetaminophen (APAP)) is one of the most commonly used analgesics in the United Kingdom and the United States. However, exceeding the maximum recommended dose can cause serious liver injury and even death. Promising APAP toxicity biomarkers are thought to add value to those used currently and clarification of the functional relationships between these biomarkers and liver injury would aid clinical implementation of an improved APAP toxicity identification framework. The framework currently used to define an APAP overdose is highly dependent upon time since ingestion and initial dose; information that is often highly unpredictable. A pharmacokinetic/pharmacodynamic (PK/PD) APAP model has been built in order to understand the relationships between a panel of biomarkers and APAP dose. Visualization and statistical tools have been used to predict initial APAP dose and time since administration. Additionally, logistic regression analysis has been applied to histology data to provide a prediction of the probability of liver injury.

Anaphylactoid Reactions to Intravenous N-Acetylcysteine during Treatment for Acetaminophen Poisoning

BACKGROUND

Anaphylactoid reactions to intravenous (IV) N-acetylcysteine (NAC) are well-recognized adverse events during treatment for acetaminophen (APAP) poisoning. Uncertainty exists regarding their incidence, severity, risk factors, and management. We sought to determine the incidence, risk factors, and treatment of anaphylactoid reactions to IV NAC in a large, national cohort of patients admitted to hospital for acetaminophen overdose.

METHODS

This retrospective medical record review included all patients initiated on the 21-h IV NAC protocol for acetaminophen poisoning in 34 Canadian hospitals between February 1980 and November 2005. The primary outcome was any anaphylactoid reaction, defined as cutaneous (urticaria, pruritus, angioedema) or systemic (hypotension, respiratory symptoms). We examined the incidence, severity and timing of these reactions, and their association with patient and overdose characteristics using multivariable analysis.

RESULTS

An anaphylactoid reaction was documented in 528 (8.2%) of 6455 treatment courses, of which 398 (75.4%) were cutaneous. Five hundred four (95.4%) reactions occurred during the first 5 h. Of 403 patients administered any medication for these reactions, 371 (92%) received an antihistamine. Being female (adjusted OR 1.24 [95%CI 1.08, 1.42]) and having taken a single, acute overdose (1.24 [95%CI 1.10, 1.39]) were each associated with more severe reactions, whereas higher serum APAP concentrations were associated with fewer reactions (0.79 [95%CI 0.68, 0.92]).

CONCLUSION

Anaphylactoid reactions to the 21-h IV NAC protocol were uncommon and involved primarily cutaneous symptoms. While the protective effects of higher APAP concentrations are of interest in understanding the pathophysiology, none of the associations identified are strong enough to substantially alter the threshold for NAC initiation.

Fewer adverse effects with a modified two-bag acetylcysteine protocol in paracetamol overdose

OBJECTIVE

Acetylcysteine (NAC), an effective antidote for paracetamol poisoning, is commonly associated with adverse reactions. This has been postulated to be related to the rapid initial infusion rate (150 mg/kg over 1 h) of the traditional three-bag protocol. We hypothesized that a slower rate would result in fewer adverse reactions. Our institution in Western Sydney moved to a modified two-bag protocol in February 2015 - first bag: 200 mg/kg over 4 h (50 mg/kg/h) and second bag: (100 mg/kg over 16 h).

METHODS

Data was extracted from our database on paracetamol overdoses treated with NAC from August 2010 to September 2016. We compared adverse reactions in patients receiving the modified two-bag protocol with a historical control (traditional three-bag regimen with initial bolus of 150 mg/kg/h).

RESULTS

Over the study period 1011 paracetamol poisonings presented to our toxicology service, of which 476 required NAC (three-bag = 313, two-bag = 163). Demographic characteristics of the two groups were similar. Fewer anaphylactoid reactions (itch, rash, and swelling) occurred using the two-bag regimen (14% versus 5%, p = .002), a relative reduction of 66%. Similarly, there were fewer prescriptions of anti-allergy medications in the two-bag group (11% versus 4%, p = .01). There was no difference in incidence of hepatotoxicity.

CONCLUSIONS

Adverse reactions to NAC were less common with the two-bag regimen. These results add to the accumulating evidence that reducing the initial NAC infusion rate reduces the risk of adverse reactions.

Development of an organ failure score in acute liver failure for transplant selection and identification of patients at high risk of futility

INTRODUCTION

King's College Hospital criteria are currently used to select liver transplant candidates in acetaminophen-related acute liver failure (ALF). Although widely accepted, they show a poor sensitivity in predicting pre-transplant mortality and cannot predict the outcome after surgery. In this study we aimed to develop a new prognostic score that can allow patient selection for liver transplantation more appropriately and identify patients at high risk of futile transplantation.

METHODS

We analysed consecutive patients admitted to the Royal Free and Beaujon Hospitals between 1990 and 2015. Clinical and laboratory data at admission were collected. Predictors of 3-month mortality in the non-transplanted patients admitted to the Royal Free Hospital were used to develop the new score, which was then validated against the Beaujon cohort. The Beaujon-transplanted group was also used to assess the ability of the new score in identifying patients at high risk of transplant futility.

RESULTS

152 patients were included of who 44 were transplanted. SOFA, CLIF-C OF and CLIF-ACLF scores were the best predictors of 3-month mortality among non-transplanted patients. CLIF-C OF score and high dosages of norepinephrine requirement were the only significant predictors of 3-month mortality in the non-transplanted patients, and therefore were included in the ALF-OFs score. In non-transplanted patients, ALF-OFs showed good performance in both exploratory (AUC = 0.89; sensitivity = 82.6%; specificity = 89.5%) and the validation cohort (AUC = 0.988; sensitivity = 100%; specificity = 92.3%). ALF-OFs score was also able to identify patients at high risk of transplant futility (AUC = 0.917; sensitivity = 100%; specificity = 79.2%).

CONCLUSION

ALF-OFs is a new prognostic score in acetaminophen-related ALF that can predict both the need for liver transplant and high risk of transplant futility, improving candidate selection for liver transplantation.

Are some people at increased risk of paracetamol-induced liver injury? A critical review of the literature

Purpose

Paracetamol is one of the world’s most commonly used drugs. In overdose, it is well established to be hepatotoxic. The aim of this review was to identify factors that have been, or actually are, associated with the development of liver injury after paracetamol exposure in humans.

Method

Google Scholar and PubMed were searched on various dates between December 2016 and March 2017. Papers identified had their references analysed for further studies that might be relevant.

Results

At the time of writing, there was little good quality clinical evidence—from studies of paracetamol overdose or therapeutic use—to suggest that any groups of people are relatively protected from, or are at greater risk of, liver injury. The factors that were historically used to indicate higher risk in the UK have no good quality clinical evidence to support their re-introduction into clinical practice. The safe (and still effective) oral dose of paracetamol in patients weighing less than 50 kg has not been established.

Conclusion

There is no patient group that is unequivocally at elevated risk of paracetamol-induced liver toxicity. We propose two clinical scenarios that warrant further research. Firstly, there is a need to establish whether the dose of paracetamol should be reduced in patients with low body weight. Secondly, if or when genomic information regarding individual patients becomes readily available to inform prescribing, we propose the contribution of the genome to paracetamol toxicity should be re-investigated with robustly designed studies. Such studies could enhance the safe use of one of the most frequently taken drugs.

Electronic supplementary material

The online version of this article (10.1007/s00228-017-2356-6) contains supplementary material, which is available to authorized users.

General hospital costs in England of medical and psychiatric care for patients who self-harm: a retrospective analysis

BACKGROUND

Self-harm is an extremely common reason for hospital presentation. However, few estimates have been made of the hospital costs of assessing and treating self-harm. Such information is essential for planning services and to help strengthen the case for investment in actions to reduce the frequency and effects of self-harm. In this study, we aimed to calculate the costs of hospital medical care associated with a self-harm episode and the costs of psychosocial assessment, together with identification of the key drivers of these costs.

METHODS

In a retrospective analysis, we estimated hospital resource use and care costs for all presentations for self-harm to the John Radcliffe Hospital (Oxford, UK), between April 1, 2013, and March 31, 2014. Episode-related data were provided by the Oxford Monitoring System for Self-harm and we linked these with financial hospital records to quantify costs. We assessed time and resources allocated to psychosocial assessments through discussion with clinical and managerial staff. We then used generalised linear models to investigate the associations between hospital costs and methods of self-harm.

FINDINGS

Between April 1, 2013, and March 31, 2014, 1647 self-harm presentations by 1153 patients were recorded. Of these, 1623 (99%) presentations by 1140 patients could be linked with hospital finance records. 179 (16%) patients were younger than 18 years. 1150 (70%) presentations were for self-poisoning alone, 367 (22%) for self-injury alone, and 130 (8%) for a combination of methods. Psychosocial assessments were made in 75% (1234) of all episodes. The overall mean hospital cost per episode of self-harm was £809. Costs differed significantly between different types of self-harm: self-injury alone £753 (SD 2061), self-poisoning alone £806 (SD 1568), self-poisoning and self-injury £987 (SD 1823; p<0·0001). Costs were mainly associated with the type of health-care service contact such as inpatient stay, intensive care, and psychosocial assessment. Mean costs of psychosocial assessments were £228 for adults and £392 for individuals younger than 18 years.

INTERPRETATION

If our findings are extrapolated to England, the estimated overall annual cost of general hospital management of self-harm is £162 million per year. More use of psychosocial assessment and other preventive measures, especially for young people and against self-poisoning, could potentially lower future costs at a time of major cost pressures in the NHS.

FUNDING

National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research, Care Oxford at Oxford Health NHS Foundation Trust, and Department of Health.

Student-selected component in the medical curriculum: investigations and psychiatric referral for paracetamol overdose in an accident and emergency department

BACKGROUND

A student-selected component (SSC) of the medical curriculum requires the student to be self-directed in locating and undertaking a placement in a clinical specialty of their choosing and completing a project. The clinical area for experience was an accident and emergency department, and our topic was a focused audit on the investigations and referral for paracetamol overdose. The purpose of this paper is twofold: to reflect on the education value to medical students of an SSC in a medical curriculum, and to highlight learning and understanding through completion of an audit.

MATERIALS AND METHODS

An audit approach was applied. The aim of the project study was to investigate the level of compliance with best-practice guidelines for investigations and psychiatric referral in paracetamol overdose.

RESULTS

A total of 40 cases meeting the inclusion criteria were randomly selected. The sample had a mean age of 27 years, of whom 70.5% were female, and the ingested dose of paracetamol ranged from 0.864 to 80 g. Paracetamol abuse may present as intentional and unintentional overdose. In our study, 85% of cases were identified as intentional overdose and 76% had a history of psychiatric illness. Generally, medical management was compliant with guidelines, with some minor irregularities. The international normalized ratio was the most underperformed test.

CONCLUSION

Our choice of topic, paracetamol overdose, contributed to our understanding of the breadth of factors to be considered in the emergency medical management of a patient. In this regard, we had the benefit of understanding how the diagnostic and therapeutic factors, when applied in accordance with best-practice guidelines, work very effectively. The SSC impacted positively on our cognitive, personal, and professional development. In facilitating the student with choice, the SSC encouraged self-direction and proactivity. We gained experience in the discipline of research and acquired some skills in independent thinking and analysis.

Oral paracetamol (acetaminophen) for cancer pain

BACKGROUND

Pain is a common symptom with cancer, and 30% to 50% of all people with cancer will experience moderate to severe pain that can have a major negative impact on their quality of life. Non-opioid drugs are commonly used to treat mild to moderate cancer pain, and are recommended for this purpose in the WHO cancer pain treatment ladder, either alone or in combination with opioids.A previous Cochrane review that examined the evidence for nonsteroidal anti-inflammatory drugs (NSAIDs) or paracetamol, alone or combined with opioids, for cancer pain was withdrawn in 2015 because it was out of date; the date of the last search was 2005. This review, and another on NSAIDs, updates the evidence.

OBJECTIVES

To assess the efficacy of oral paracetamol (acetaminophen) for cancer pain in adults and children, and the adverse events reported during its use in clinical trials.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase from inception to March 2017, together with reference lists of retrieved papers and reviews, and two online study registries.

SELECTION CRITERIA

We included randomised, double-blind, studies of five days' duration or longer, comparing paracetamol alone with placebo, or paracetamol in combination with an opioid compared with the same dose of the opioid alone, for cancer pain of any intensity. Single-blind and open studies were also eligible for inclusion. The minimum study size was 25 participants per treatment arm at the initial randomisation.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched for studies, extracted efficacy and adverse event data, and examined issues of study quality and potential bias. We did not carry out any pooled analyses. We assessed the quality of the evidence using GRADE and created a 'Summary of findings' table.

MAIN RESULTS

Three studies in adults satisfied the inclusion criteria, lasting up to one week; 122 participants were randomised initially, and 95 completed treatment. We found no studies in children. One study was parallel-group, and two had a cross-over design. All used paracetamol as an add-on to established treatment with strong opioids (median daily morphine equivalent doses of 60 mg, 70 mg, and 225 mg, with some participants taking several hundred mg of oral morphine equivalents daily). Other non-paracetamol medication included non-steroidal anti-inflammatory drugs (NSAIDs), tricyclic antidepressants, or neuroleptics. All studies were at high risk of bias for incomplete outcome data and small size; none was unequivocally at low risk of bias.None of the studies reported any of our primary outcomes: participants with pain reduction of at least 50%, and at least 30%, from baseline; participants with pain no worse than mild at the end of the treatment period; participants with Patient Global Impression of Change (PGIC) of much improved or very much improved (or equivalent wording). What pain reports there were indicated no difference between paracetamol and placebo when added to another treatment. There was no convincing evidence of paracetamol being different from placebo with regards to quality of life, use of rescue medication, or participant satisfaction or preference. Measures of harm (serious adverse events, other adverse events, and withdrawal due to lack of efficacy) were inconsistently reported and provided no clear evidence of difference.Our GRADE assessment of evidence quality was very low for all outcomes, because studies were at high risk of bias from several sources.

AUTHORS' CONCLUSIONS

There is no high-quality evidence to support or refute the use of paracetamol alone or in combination with opioids for the first two steps of the three-step WHO cancer pain ladder. It is not clear whether any additional analgesic benefit of paracetamol could be detected in the available studies, in view of the doses of opioids used.

Sirtuin-Activating Compounds (STACs) Alleviate D-Galactosamine/Lipopolysaccharide-Induced Hepatotoxicity in Rats: Involvement of Sirtuin 1 and Heme Oxygenase 1

Sirtuin activating compounds (STACs) attenuate various type of liver insults through mechanisms which are not fully understood. In the present study, we investigated the ameliorative potential of quercetin (natural polyphenol) and SRT1720 (synthetic SIRT1 activator) against D-galactosamine/lipopolysaccharide-induced hepatotoxicity (an experimental model of acute liver failure). Moreover, we compared and contrasted the roles of stress responsive enzymes, sirtuin 1 (SIRT1) and heme oxygenase 1 (HO-1) in hepatoprotection/ hepatotoxicity. Liver injury was induced in male Wistar rats by intraperitoneal injection of D-galactosamine (400 mg/kg) and lipopolysaccharide (10 µg/kg). Some animals were pretreated with quercetin (50 mg/kg i.p.) or SRT1720 (5 mg/kg i.p.). Twenty-four hours later, the effects of these treatments were evaluated by biochemical studies and Western blot. D-GalN/LPS treatment upregulated HO-1 expression, downregulated SIRT1 expression, decreased AST:ALT ratio and markedly increased bilirubin, catalase and conjugated diene levels. Pretreatment of D-GalN/LPS rats with either quercetin or SRT1720 returned SIRT1 expression, HO-1 expression and all the aforementioned markers towards normal. Collectively, these findings suggest that elevated HO-1 and low SIRT1 expressions are involved in the pathogenesis of D-GalN/LPS-induced hepatotoxicity. Drugs that downregulate HO-1 and/or upregulate SIRT1 seem to have antihepatotoxic effects and need further exploration.