The chemokine CXCL14 is a novel early prognostic biomarker for poor outcome in acetaminophen-induced acute liver failure

BACKGROUND AND AIMS

Patients with acetaminophen-induced acute liver failure are more likely to die while on the liver transplant waiting list than those with other causes of acute liver failure. Therefore, there is an urgent need for prognostic biomarkers that can predict the need for liver transplantation early after an acetaminophen overdose.

APPROACH AND RESULTS

We evaluated the prognostic potential of plasma chemokine C-X-C motif ligand 14 (CXCL14) concentrations in patients with acetaminophen (APAP) overdose (n=50) and found that CXCL14 is significantly higher in nonsurviving patients compared to survivors with acute liver failure ( p < 0.001). Logistic regression and AUROC analyses revealed that CXCL14 outperformed the MELD score, better discriminating between nonsurvivors and survivors. We validated these data in a separate cohort of samples obtained from the Acute Liver Failure Study Group (n = 80), where MELD and CXCL14 had similar AUC (0.778), but CXCL14 demonstrated higher specificity (81.2 vs. 52.6) and positive predictive value (82.4 vs. 65.4) for death or need for liver transplantation. Next, combining the patient cohorts and using a machine learning training/testing scheme to mimic the clinical scenario, we found that CXCL14 outperformed MELD based on AUC (0.821 vs. 0.787); however, combining MELD and CXCL14 yielded the best AUC (0.860).

CONCLUSIONS

We find in 2 independent cohorts of acetaminophen overdose patients that circulating CXCL14 concentration is a novel early prognostic biomarker for poor outcomes, which may aid in guiding decisions regarding patient management. Moreover, our findings reveal that CXCL14 performs best when measured soon after patient presentation to the clinic, highlighting its importance for early warning of poor prognosis.

Intestinal injury in paracetamol overdose (ATOM-8)

BACKGROUND AND AIM

Paracetamol, a widely used medication, is known for its delayed hepatotoxicity in cases of overdose. However, the potential for intestinal toxicity resulting from very high paracetamol concentrations during absorption is not well explored. This study aims to investigate the presence of intestinal toxicity and its correlation with observations in early and late paracetamol toxicity.

METHODS

Serial samples of 30 patients with acute paracetamol overdose (> 10 g or 200 mg/kg) were prospectively tested. Markers of enterocyte damage, including plasma intestinal fatty acid binding protein (IFABP) and selected gut-related microRNAs (miR-21, miR-122, miR-194, and miR-215), were analyzed. Sub-analysis was performed on patients presenting with hyperlactatemia defined as a lactate greater than 2 mmol/L within 12 h post ingestion.

RESULTS

In paracetamol overdose patients, median plasma IFABP was significantly elevated compared with healthy controls (720 μg/L [interquartile range, IQR, 533-1644] vs 270 μg/L [IQR 153-558], P < 0.001). Four patients had early hyperlactatemia and had significantly higher median plasma IFABP compared with those without early hyperlactatemia (3028 μg/L [IQR 1399-3556] vs 574 μg/L [IQR 526-943], P = 0.007). Furthermore, two microRNAs (miR-122 and miR-215) were downregulated in early hyperlactatemia (P = 0.019 and P = 0.006, respectively). Plasma IFABP concentrations correlated with paracetamol concentration (Spearman's r = 0.55) and lactate (r = 0.60).

CONCLUSIONS

Paracetamol overdose causes concentration-related intestinal toxicity, and this is a possible explanation for the early hyperlactatemia syndrome. Intestinal toxicity has potential impacts on pharmacokinetics of other agents ingested and on the evolution of hepatotoxicity. Further studies are required to explore the mechanisms and prognostic implications of intestinal toxicity.

Paracetamol overdose in Danish children and adolescents during the Covid-19 restrictions

INTRODUCTION

To assess the effect of long-term isolation on the mental state of Danish youth. This study aimed to investigate trends in paracetamol overdoses among people under 18 years of age in Denmark during Covid-19 restrictions as an indicator of mental health.

METHODS

All patients under the age of 18 years presenting with paracetamol overdose at one of the 18 paediatric departments in Denmark from 2016 to 2021 were included. They were identified in all Danish hospital databases using specific diagnostic codes.

RESULTS

From 2016 to 2021, a total of 3,217 people under 18 years of age were admitted for paracetamol overdose. Among these, 86% (n = 2,755) were girls and 14% (n = 462) were boys. During 2020, a slight (7%) decrease in admissions was observed among both boys and girls compared with the preceding four-year mean value. In 2021, the number of overdoses among girls exceeded by 35% the former all-time high from 2016. Furthermore, the number of overdoses among girls exceeded the pre-four-year period mean value by 43%. Among boys, an 8% increase was seen from the highest ever previous value recorded in 2019 and a 23% increase compared with the previous four-year mean value.

CONCLUSIONS

During the first year of restrictions, a slight decrease in paracetamol overdoses was observed, possibly associated with limited accessibility. The second year showed a considerable increase in paracetamol overdoses, which may imply an affected mental state among youth during the prolonged lockdown restrictions as seen in previous epidemics. Therefore, further studies are warranted to develop a pandemic preparedness plan to protect general mental health.

FUNDING

None.

TRIAL REGISTRATION

Not relevant.

Assessing the impact of a new medical toxicology service on the treatment of paracetamol overdose at a large tertiary care hospital

BACKGROUND

Paracetamol overdose is the most common cause of acute liver failure in the United States. Administration of acetylcysteine is the standard of care for this intoxication. Laboratory values and clinical criteria are used to guide treatment duration, but decision-making is nuanced and often complex and difficult. The purpose of this study was to evaluate the effect of the introduction of a medical toxicology service on the rate of errors in the management of paracetamol overdose.

METHODS

This was a single center, retrospective, cohort evaluation. Patients with suspected paracetamol overdose were divided into two groups: those attending in the 1 year period before and those in the 1 year after the introduction of the medical toxicology service. The primary outcome was the frequency of deviations from the established management of paracetamol intoxication, using international guidelines as a reference.

RESULTS

Fifty-four patients were eligible for the study (20 pre-toxicology-service, 34 post-toxicology-service). The frequency of incorrect therapeutic decisions was significantly lower in the post-toxicology service implementation versus the pre-implementation group (P = 0.005).

DISCUSSION

Our study suggests that a medical toxicology service reduces the incidence of management errors, including the number of missed acetylcysteine doses in patients with paracetamol overdose. The limitations include the retrospective study design and that the study was conducted at a single center, which may limit generalizability.

CONCLUSIONS

The implementation of a medical toxicology service was associated with a decrease in the number of errors in the management of paracetamol overdose.

Is Two Better Than Three? A Systematic Review of Two-bag Intravenous N-acetylcysteine Regimens for Acetaminophen Poisoning

Introduction

Acetaminophen poisoning is commonly treated by emergency physicians. First-line therapy is N-acetylcysteine (NAC), traditionally administered intravenously via a US Food and Drug Administration (FDA)-approved three-bag protocol in which each bag has a unique concentration and infusion duration. Recently, simplified, off-label two-bag NAC infusion protocols have become more common. The purpose of this review is to summarize the effectiveness and safety of two-bag NAC.

Methods

We undertook a comprehensive search of PubMed, EMBASE, and MEDLINE from inception to December 13, 2022, for articles describing human acetaminophen poisonings treated with two-bag NAC, defined as any regimen involving two discrete infusions in two separate bags. Outcomes included effectiveness (measured by incidence of liver injury); incidence of non-allergic anaphylactoid reactions (NAAR); gastrointestinal, cutaneous, and systemic reactions; treatments for NAARs; incidence of NAC-related medication errors; and delays or interruptions in NAC administration.

Results

Twelve articles met final inclusion, 10 of which compared two-bag NAC to the three-bag regimen. Nine articles evaluated the two-bag/20-hour regimen, a simplified version of the FDA-approved three-bag regimen in which the traditional first and second bags are combined into a single four-hour infusion. Nine articles assessed comparative effectiveness of two-bag NAC in terms of liver injury, most commonly assessed for by incidence of hepatotoxicity (aspartate aminotransferase or alanine aminotransferase >1,000 international units per liter). No difference in liver injury was observed between two-bag and three-bag regimens. Of nine articles comparing incidence of NAARs, eight demonstrated statistically fewer NAARs with two-bag regimens, and one showed no difference. In seven articles evaluating treatment for NAARs (antihistamines, corticosteroids, epinephrine), all showed that patients received fewer medications for NAARs with two-bag NAC. Three articles evaluated NAC-related medication errors; two demonstrated no difference, while one study evaluating only children showed fewer errors with two-bag NAC. Two studies evaluated delays and/or interruptions in NAC infusions; both favored two-bag NAC.

Conclusion

For patients with acetaminophen poisoning, two-bag NAC regimens appear to have similar outcomes to the traditional three-bag regimen in terms of liver injury. Two-bag NAC regimens are associated with fewer adverse events and fewer treatments for those events than the three-bag regimen and fewer interruptions in antidotal therapy.

Chrysanthemi Flos extract alleviated acetaminophen-induced rat liver injury via inhibiting oxidative stress and apoptosis based on network pharmacology analysis

CONTEXT

Acetaminophen (APAP) overdose is the leading cause of drug-induced liver injury. Bianliang ziyu, a variety of Chrysanthemum morifolium Ramat. (Asteraceae), has potential hepatoprotective effect. However, the mechanism is not clear yet.

OBJECTIVE

To investigate the hepatoprotective activity and mechanism of Bianliang ziyu flower ethanol extract (BZE) on APAP-induced rats based on network pharmacology.

MATERIALS AND METHODS

Potential pathways of BZE were predicted by network pharmacology. Male Sprague-Dawley rats were pre-treated with BZE (110, 220 and 440 mg/kg, i.g.) for eight days, and then APAP (800 mg/kg, i.g.) was used to induce liver injury. After 24 h, serum and liver were collected for biochemical detection and western blot measurement.

RESULTS

Network pharmacology indicated that liver-protective effect of BZE was associated with its antioxidant and anti-apoptotic efficacy. APAP-induced liver pathological change was alleviated, and elevated serum AST and ALT were reduced by BZE (440 mg/kg) (from 66.45 to 22.64 U/L and from 59.59 to 17.49 U/L, respectively). BZE (440 mg/kg) reduced the ROS to 65.50%, and upregulated SOD and GSH by 212.92% and 175.38%, respectively. In addition, BZE (440 mg/kg) increased levels of p-AMPK, p-GSK3β, HO-1 and NQO1, ranging from 1.66- to 10.29-fold compared to APAP group, and promoted nuclear translocation of Nrf2. BZE also inhibited apoptosis induced by APAP through the PI3K-Akt pathway and restored the ability of mitochondrial biogenesis.

DISCUSSION AND CONCLUSIONS

Our study demonstrated that BZE protected rats from APAP-induced liver injury through antioxidant and anti-apoptotic pathways, suggesting BZE could be further developed as a potential liver-protecting agent.

Delayed administration of N-acetylcysteine blunts recovery after an acetaminophen overdose unlike 4-methylpyrazole

N-acetylcysteine (NAC) is the only clinically approved antidote against acetaminophen (APAP) hepatotoxicity. Despite its efficacy in patients treated early after APAP overdose, NAC has been implicated in impairing liver recovery in mice. More recently, 4-methylpyrazole (4MP, Fomepizole) emerged as a potential antidote in the mouse APAP hepatotoxicity model. The objective of this manuscript was to verify the detrimental effect of NAC and its potential mechanism and assess whether 4MP has the same liability. C57BL/6J mice were treated with 300 mg/kg APAP; 9h after APAP and every 12h after that, the animals received either 100 mg/kg NAC or 184.5 mg/kg 4MP. At 24 or 48h after APAP, parameters of liver injury, mitochondrial biogenesis and cell proliferation were evaluated. Delayed NAC treatment had no effect on APAP-induced liver injury at 24h but reduced the decline of plasma ALT activities and prevented the shrinkage of the areas of necrosis at 48h. This effect correlated with down-regulation of key activators of mitochondrial biogenesis (AMPK, PGC-1α, Nrf1/2, TFAM) and reduced expression of Tom 20 (mitochondrial mass) and PCNA (cell proliferation). In contrast, 4MP attenuated liver injury at 24h and promoted recovery at 48h, which correlated with enhanced mitochondrial biogenesis and hepatocyte proliferation. In human hepatocytes, 4MP demonstrated higher efficacy in preventing cell death compared to NAC when treated at 18h after APAP. Thus, due to the wider treatment window and lack of detrimental effects on recovery, it appears that at least in preclinical models, 4MP is superior to NAC as an antidote against APAP overdose.

A metabolomic analysis of thiol response for standard and modified N-acetyl cysteine treatment regimens in patients with acetaminophen overdose

N-acetylcysteine (NAC) is an antidote to prevent acetaminophen (paracetamol-APAP)-induced acute liver injury (ALI). The 3-bag licensed 20.25 h standard regimen, and a 12 h modified regimen, are used to treat APAP overdose. This study evaluated the redox thiol response and APAP metabolites, in patients with a single APAP overdose treated with either the 20.25 h standard or 12 h modified regimen. We used liquid chromatography tandem mass spectrometry to quantify clinically important oxidative stress biomarkers and APAP metabolites in plasma samples from 45 patients who participated in a randomized controlled trial (SNAP trial). We investigated the time course response of plasma metabolites at predose, 12 h, and 20.25 h post-start of NAC infusion. The results showed that the 12 h modified regimen resulted in a significant elevation of plasma NAC and cysteine concentrations at 12 h post-infusion. We found no significant alteration in the metabolism of APAP, mitochondrial, amino acids, and other thiol biomarkers with the two regimens. We examined APAP and purine metabolism in overdose patients who developed ALI. We showed the major APAP-metabolites and xanthine were significantly higher in patients with ALI. These biomarkers correlated well with alanine aminotransferase activity at admission. Receiver operating characteristic analysis showed that at admission, plasma APAP-metabolites and xanthine concentrations were predictive for ALI. In conclusion, a significantly higher redox thiol response with the modified NAC regimen at 12 h postdose suggests this regimen may produce greater antioxidant efficacy. At baseline, plasma APAP and purine metabolites may be useful biomarkers for early prediction of APAP-induced ALI.

Protective role of Chlorella vulgaris with Thiamine against Paracetamol induced toxic effects on haematological, biochemical, oxidative stress parameters and histopathological changes in Wistar rats

Paracetamol is extensively consumed as an analgesic and antipyretic drug, but at a high dose level, it leads to deleterious side effects, such as hepatic and nephrotoxicity. This research aimed to estimate the prophylactic efficacy of Chlorella vulgaris and/or thiamine against paracetamol (P) induced hepatorenal and cardiac toxicity. Forty-eight female Wistar rats were randomly divided into eight equal groups (n = 6 rats). Group 1, normal control group. Group 2, Paracetamol group. Groups 3, 4 and 5 were treated with Silymarin drug, Chlorella vulgaris alga, Chlorella vulgaris alga supplemented with thiamine, respectively daily for 7 successive days, then all were administered Paracetamol (2gm/kg. bwt.). While, Groups 6, 7 and 8 were treated by Silymarin, Chlorella vulgaris alga, Chlorella vulgaris supplemented with thiamine, respectively daily for 7 successive days without paracetamol administration. Our results clarified that Paracetamol toxicity caused significant adverse effects on hematological, serum biochemical parameters, and oxidant -antioxidant status as well as histopathological picture of heart, liver, and kidney. However, in the Paracetamol intoxicated groups pretreatment either with Chlorella vulgaris alone or plus thiamine successfully improved the undesirable deleterious effects of paracetamol, and restored almost all variables to near their control levels. This study has finished to that oxidative stress participates in the pathogenesis of paracetamol-induced toxicity in rats and using Chlorella vulgaris alga either alone or plus thiamine alongside their health benefits can protect against oxidative harmful effects induced by paracetamol through their free radical scavenging and powerful antioxidant effects, and they can be used as propylactic agents against paracetamol-induced toxicity.

Orostachys japonicus ameliorates acetaminophen-induced acute liver injury in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Orostachys japonicus A. Berger (O. japonicus), referred to as Wa-song in Korea is a traditional and herbal medicine. Even though it has been traditionally used to treat inflammation- and toxicity-related diseases, the effects of ethanol extract of O. japonicus (OJE) on acetaminophen (N-acetyl-p-aminophenol, APAP) overdose-induced hepatotoxicity have not been determined yet.

AIM OF THE STUDY

The present study was aimed to investigate the effects of OJE against APAP-induced acute liver injury (ALI) and explore the underlying mechanisms.

MATERIALS AND METHODS

Mice were treated orally with OJE (50, 100, or 200 mg/kg) for seven days before APAP (300 mg/kg) injection. After 12 h of APAP treatment, serum and liver tissues were collected. An in vitro system using primary hepatocytes was also applied in this study.

RESULTS

Pretreatment with OJE, especially at a dose of 200 mg/kg, reduced APAP overdose-induced ALI in mice, as evidenced by decreased serum alanine/aspartate aminotransferase levels, histopathological damage, and inflammation. Consistently, OJE pretreatment reduced the gene transcription of cytochrome P450 (CYP) 3A11 and CYP1A2 in livers of mice injected with or without APAP, at least in part, via inactivation of nuclear receptor pregnane X receptor (PXR). Furthermore, the role of PXR in mediating the OJE regulation of CYPs was confirmed in primary hepatocytes, which showed that OJE pretreatment inhibited PXR activity and APAP hepatotoxicity enhanced by pregnenolone 16α-carbonitrile, a mouse agonist of PXR. Besides, the antioxidative activity provided by OJE, involving increases in hepatic glutathione (GSH) content and decreases in malondialdehyde levels, has been shown to exert hepatoprotective effects in normal and injured livers. Moreover, APAP-activated c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) in mice liver were indirectly inhibited by pretreatment with OJE.

CONCLUSIONS

Taken together, our findings showed that OJE attenuated APAP-induced ALI by decreasing APAP-metabolizing enzymes via inactivation of PXR and the restoration of hepatic GSH content. Therefore, OJE could be a promising hepatoprotective agent.

Paracetamol self-poisoning: Epidemiological study of trends and patient characteristics from the multicentre study of self-harm in England

BACKGROUND

Paracetamol is frequently used for intentional self-poisoning, especially in the UK, despite pack size restrictions introduced in 1998. Knowing more about paracetamol self-poisoning may identify further approaches to prevention.

METHODS

We used data from the Multicentre Study of Self-harm in England for 2004-2014 to calculate incidence rates of presentations to Emergency Departments following self-poisoning with pure paracetamol alone. National estimates for England for 2011-2014 were extrapolated using indirect age-standardised rates. The characteristics of individuals taking paracetamol overdoses and the size of the overdoses were investigated.

RESULTS

A third of 54,863 intentional overdoses presenting to the five Emergency Departments involved paracetamol without other drugs (N = 18,011), taken by 13,171 individuals (63.4% female).  The proportion of paracetamol self-poisonings was similar in the three centres. Extrapolation suggested there were approximately 50,000 paracetamol overdoses in England annually during 2011-2014. Females had higher rates of paracetamol overdose than males.  Males and older individuals took larger overdoses.  Nearly a quarter of individuals (24.2%) consumed more than 32 tablets. Alcohol was involved in 53.7% of paracetamol overdoses.

LIMITATIONS

Data were collected in three centres with predominantly urban populations. Extrapolation from local to national rates should be interpreted with caution.

CONCLUSIONS

Paracetamol overdose remains a major problem in the UK. It is more common in females and younger patients, but males and older patients consume larger overdoses. Consideration should be given to further restriction in pack sizes and sources of sales, in keeping with those of several other European countries.

The Clinical Value of Routine Acetaminophen Level Screening in Pediatric Patients Presenting to the Emergency Department

BACKGROUND

Acetaminophen is the most common drug involved in pediatric poisonings, both intentionally and accidentally, and is the leading cause of acute liver failure among all age groups.

OBJECTIVES

To define the characteristics of patients admitted to a pediatric emergency department (ED) where serum acetaminophen concentrations were measured, and to determine which variables are associated with significant risk of acetaminophen toxicity.

METHODS

Acetaminophen serum concentrations were measured, in a retrospective case series, of patients younger than 18 years who had been admitted to the ED at Shamir Medical Center between 1 January 2008 and 31 December 2015.

RESULTS

During the study period 180,174 children were admitted to the ED. Acetaminophen serum concentrations were measured in 209 (0.12%) patients. Mean age was 12.4 ± 5.9 years. Elevated liver enzymes were found in 12 patients, 5 of whom had documented acute liver injury. All five were older than 11years.Two cases of acute liver injury were attributable to acetaminophen ingestion. In both cases the cause was intentional overdose. Univariate analysis showed a significant (P < 0.05) correlation between detectable acetaminophen blood level and a positive history of drug or acetaminophen ingestion, and suicide attempt. Not all children with non-severe acetaminophen poisoning had been diagnosed during the study period. A positive history of acetaminophen ingestion was associated with a 28-fold higher risk for detectable acetaminophen blood level.

CONCLUSIONS

In the absence of a positive history of acetaminophen ingestion and in young children with accidental intoxication, the risk of hepatotoxicity is relatively low.

Regulation of macrophage activation in the liver after acute injury: Role of the fibrinolytic system

The liver functions, in part, to prevent exposure of the body to potentially harmful substances ingested in the diet. While it is highly efficient at accomplishing this, it is frequently prone to liver injury due to the biotransformation of xenobiotics into toxic metabolites. To counter this injury, the liver has evolved a unique capacity to rapidly and efficiently repair itself. Successful resolution of acute liver injury relies on hepatic macrophage populations that orchestrate the reparative response. After injury, Kupffer cells, the resident macrophages of the liver, become activated and secrete proinflammatory cytokines. These cytokines recruit other immune cells, including monocyte-derived macrophages, to the liver where they contribute to the repair process. Monocyte-derived macrophages traffic into the necrotic foci where they rapidly phagocytose dead cell debris. Simultaneous with this process, these cells change phenotype from a proinflammatory macrophage to a pro-restorative macrophage that produce pro-mitogenic growth factors and anti-inflammatory cytokines. Ultimately this process triggers resolution of inflammation, and along with proliferation of other hepatic cells, restores the liver architecture and function. While the mechanisms regulating specific macrophage functions during repair remain to be elucidated, recent studies indicate a key role for the fibrinolytic system in coordinating macrophage function during repair. In this review, we will highlight the function and role of hepatic macrophages in repair after acute liver injury, and will discuss the role of the fibrinolytic enzyme, plasmin, in regulation of these various processes.

Trends in emergency department visits for acetaminophen-related poisonings: 2011-2019

We examined trends in emergency department (ED) presentation rates for acetaminophenrelated poisonings across Canada. A total of 27123 cases of poisoning were seen in the electronic Canadian Hospitals Injury Reporting and Prevention Program (eCHIRPP) sentinel sites between April 2011 and February 2019; of these, 13.7% were related to acetaminophen use. A significant decreasing trend for both sexes was observed for unintentional poisonings (males: -10.3%; females: -8.0%). For intentional poisonings, there was a significant decrease among females only (-5.9%). Females have consistently displayed higher rates of ED presentations for both unintentional and intentional poisoning.

Circulating microRNA Profiles in Acetaminophen Toxicity

INTRODUCTION

Acetaminophen toxicity has been associated with elevation of microRNAs. The present study was to evaluate overall microRNA profiles and previously identified microRNAs to differentiate acetaminophen (APAP) toxicity from other causes of transaminase elevation.

METHODS

This was an observational study of adults with presumed acetaminophen toxicity at presentation. Serum samples were collected every 12 hours during hospitalization. Total miRNAs were extracted from plasma and levels of 327 microRNAs were quantified using real-time polymerase chain reaction. A standard measure of miRNA expression (delta-delta cycle threshold) was calculated for each microRNAs. A two-level cluster analysis was performed using a random k-means algorithm. Demographic and clinical characteristics of each cluster were compared using ANOVA, Wilcoxon rank sum, Kruskal-Wallis, and chi-square tests. Performance of specific miRNAs of interest was also evaluated.

RESULTS

Twenty-seven subjects were enrolled (21 with a final diagnosis of acetaminophen toxicity), and a total of 61 samples were analyzed. Five clusters were identified, two of which demonstrated clear clinical patterns and included specific elevated miRNAs previously reported to be elevated in APAP toxicity patients. Features associated with clusters 1 and 5 included confirmed acetaminophen toxicity, high peak alanine aminotransferase, and late presentation. Clusters 2-4 contained lower peak microRNAs, lower peak alanine aminotransferase, and heterogeneous clinical characteristics.

CONCLUSIONS

Severe cases of acetaminophen toxicity showed two distinct patterns of microRNA elevation which were similar to previous work, while less severe cases were difficult to distinguish from non-acetaminophen-associated cases. Further work is needed to incorporate microRNA profiles into the diagnostic algorithm of acetaminophen toxicity.

The MicroRNA-based Liquid Biopsy Improves Early Assessment of Lethal Acetaminophen Poisoning: A Case Report

BACKGROUND Acetaminophen overdose is the most common cause of acute liver failure. Nevertheless, new biomarker approaches enabling early prediction of the outcome of the acetaminophen overdose are needed. Recently, using next-generation sequencing analysis of serum from human study participants we uncovered injury-specific signatures of circulating microRNAs (miRNAs) that represented underlying molecular mechanisms of toxicity. This case study is first to show the application of miRNA profiling to assess prognosis of acetaminophen poisoning. CASE REPORT The patient was admitted to the hospital following supra therapeutic acetaminophen ingestion. The patient showed elevated levels of biomarkers of hepatocellular injury alanine aminotransferase, aspartate transaminase, and glutamate dehydrogenase. Even though treatment with N-acetyl cysteine was initiated 24 hours post-ingestion, levels of alanine-aminotransferase and aspartate transaminase peaked at about 40 hours post ingestion of acetaminophen. We analyzed global circulating miRNA levels from 24 consecutive serum samples from this study participant covering the period from admission to time of death. CONCLUSIONS The resulting global miRNA profiles were compared with profiles from study participants with non-lethal acetaminophen poisoning and healthy controls. At the admission, the miRNA profiles of both lethal and non-lethal acetaminophen poisoning showed induction of cellular stress and oxidative damage. Later, the miRNA profiles of the lethal poisoning featured fibrosis and coagulation pathways while profiles of non-lethal cases resembled those of healthy study participants. Although additional confirmatory studies are needed, our case study is first to indicate that global miRNA profiles to be used as liquid biopsies have potential to facilitate the assessment of acetaminophen poisoning.

Acetaminophen poisoning-induced heart injury: a case-based review

PURPOSE

Acetaminophen (Paracetamol, APAP) poisoning is frequently implicated in self-harm. Cases of acetaminophen-associated cardiotoxicity are rare in relation to the number of patients with acetaminophen poisoning. A review of acetaminophen cardiotoxicity in 1996 concluded that there was no decisive evidence demonstrating that acetaminophen overdose has a cardiotoxic effect. This review study aimed to determine whether acetaminophen could induce heart injury.

METHODS

We searched for keywords of acetaminophen, paracetamol, cardiotoxicity, heart injury, heart damage, myocarditis, pericarditis, myocardial infarction, and myocardial ischemia in Web of Science, PubMed, Scopus, Embase, Google Scholar, and Persian databases. The search included articles published from January 1950 to October 2018 with no language restrictions.

RESULTS

The search yielded 64 citations in English; 36 of the articles were excluded as they were not relevant; 5 articles were excluded since they were duplicates, leaving 23 articles. Full-text articles of the 23 citations were obtained and reviewed. Myocardial infarction, heart dysfunction and failure, cardiac arrhythmias, pericarditis, heart cell necrosis, and sudden cardiac death were reported in acetaminophen overdose.

CONCLUSIONS

Ddysrhythmias, heart failure, and various other cardiac effects could occur following acetaminophen induced hepatic failure. However, the evidence for direct injury on cardiac tissue is weak. Graphical abstract Potential mechanisms for cardiotoxicity of acetaminophen.

Fomepizole as an Adjunctive Treatment in Severe Acetaminophen Toxicity

A 33-year-old male presented to the emergency department with a chief complaint of abdominal pain after taking #50 500 mg acetaminophen tablets over the preceding two days. He was tachycardic and tachypneic, and the initial labs were notable for acetaminophen level, 337 mg/L; AST, 137 IU/L; ALT, 194 IU/L; ABG pH, 7.24; and lactate, 4.1 mmol/L. The patient was started on IV N-Acetylcysteine (NAC) as well as given a single dose of 15 mg/kg fomepizole. The patient did remarkably well, with a peak AST of 198 IU/L, peak ALT of 301 IU/L, and peak INR of 3.1. Biochemical and animal data support fomepizole having hepatoprotective effects in acetaminophen poisoning. To our knowledge, this is the first human case of an intentional dual NAC/fomepizole regimen for severe acetaminophen toxicity.

[Simplified N-acetylcystein treatment after paracetamol overdose - new recommendations from Swedish Poisons Information Centre]

Since the late 1970s N-acetylcystein has been used as an antidote after paracetamol intoxication. The treatment is traditionally given as three consecutive infusions for 20 hours and 15 minutes. The total dose given is 300 mg/kg. Half of this amount is given as a bolus during the first 15 minutes of treatment.  This regime has proven very efficient in avoiding liver injury. However, side effects, caused by histamine release, are common (10-15%). Symptoms as flush, urticaria and, in rare cases, bronchospasm, angioedema and circulatory shock typically appear during the bolus dose and may lead to interrupted and inadequate treatment. In addition, the regime is complicated leading to a risk of administration errors. During the last years several publications have described the use of a model with two infusions instead of three. The first and the second infusions are merged and given over four hours. The third infusion and the total dose are left unchanged. This modified regime has been shown to reduce side effects and seems not to increase the risk of liver injury. As of November 1, 2019, the Swedish Poisons Information Centre will change its recommendations to the new two-infusion protocol.

Acute liver failure

Acute liver failure is a rare and severe consequence of abrupt hepatocyte injury, and can evolve over days or weeks to a lethal outcome. A variety of insults to liver cells result in a consistent pattern of rapid-onset elevation of aminotransferases, altered mentation, and disturbed coagulation. The absence of existing liver disease distinguishes acute liver failure from decompensated cirrhosis or acute-on-chronic liver failure. Causes of acute liver failure include paracetamol toxicity, hepatic ischaemia, viral and autoimmune hepatitis, and drug-induced liver injury from prescription drugs, and herbal and dietary supplements. Diagnosis requires careful review of medications taken, and serological testing for possible viral exposure. Because of its rarity, acute liver failure has not been studied in large, randomised trials, and most treatment recommendations represent expert opinion. Improvements in management have resulted in lower mortality, although liver transplantation, used in nearly 30% of patients with acute liver failure, still provides a life-saving alternative to medical management.

The hepatokine Tsukushi is released in response to NAFLD and impacts cholesterol homeostasis

Nonalcoholic fatty liver disease (NAFLD) prevails in obesity and is linked to several health complications including dyslipidemia and atherosclerosis. How exactly NAFLD induces atherogenic dyslipidemia to promote cardiovascular diseases is still elusive. Here, we identify Tsukushi (TSK) as a hepatokine induced in response to NAFLD. We show that both endoplasmic reticulum stress and inflammation promote the expression and release of TSK in mice. In humans, hepatic TSK expression is also associated with steatosis, and its circulating levels are markedly increased in patients suffering from acetaminophen-induced acute liver failure (ALF), a condition linked to severe hepatic inflammation. In these patients, elevated blood TSK levels were associated with decreased transplant-free survival at hospital discharge, suggesting that TSK could have a prognostic significance. Gain- and loss-of-function studies in mice revealed that TSK impacts systemic cholesterol homeostasis. TSK reduces circulating HDL cholesterol, lowers cholesterol efflux capacity, and decreases cholesterol-to-bile acid conversion in the liver. Our data identify the hepatokine TSK as a blood biomarker of liver stress that could link NAFLD to the development of atherogenic dyslipidemia and atherosclerosis.

[Improved and harmonised laboratory analysis of paracetamol provides safer assessment of poisoning cases]

Toxicological analysis is an important part of the acute treatment of various intoxications. Rapid laboratory responses are important for the patient to be assessed and treated correctly, and also to exclude poisoning and thus avoid unjustified and costly overtreatment. In Sweden, paracetamol (acetaminophen) is one of the most common pharmaceuticals in drug poisoning. Paracetamol overdose can cause severe liver damage unless treated early with the antidote acetylcysteine. A nation-wide initiative for improved laboratory measurement of paracetamol in plasma/serum samples has resulted in a marked reduction in the inter-laboratory coefficient of variation to generally below 10%. The introduction of a harmonized national reporting range for plasma/serum paracetamol covering at least 50-5 000 µmol/l was also recommended. This initiative will hopefully contribute to better healthcare from both a patient and health resource perspective in cases of paracetamol poisoning.

Hepatoprotective Actions of Ascorbic Acid, Alpha Lipoic Acid and Silymarin or Their Combination Against Acetaminophen-Induced Hepatotoxicity in Rats

Background and objectives: Ascorbic acid, alpha lipoic acid (ALA) and silymarin are well-known antioxidants that have hepatoprotective effects. This study aims to investigate the effects of these three compounds combined with attenuating drug-induced oxidative stress and cellular damage, taking acetaminophen (APAP)-induced toxicity in rats as a model both in vivo and in vitro. Materials and Methods: Freshly cultured primary rat hepatocytes were treated with ascorbic acid, ALA, silymarin and their combination, both with and without the addition of APAP to evaluate their in vitro impact on cell proliferation and mitochondrial activity. In vivo study was performed on rats supplemented with the test compounds or their combination for one week followed by two toxic doses of APAP. Results: Selected liver function tests and oxidative stress markers including superoxide dismutase (SOD), malondialdehyde (MDA) and oxidized glutathione (GSSG) were detected. The in vivo results showed that all three pretreatment compounds and their combination prevented elevation of SOD and GSSG serum levels indicating a diminished burden of oxidative stress. Moreover, ascorbic acid, ALA and silymarin in combination reduced serum levels of liver enzymes; however, silymarin markedly maintained levels of all parameters to normal ranges. Silymarin either alone or combined with ascorbic acid and ALA protected cultured rat hepatocytes and increased cellular metabolic activity. The subjected agents were capable of significantly inhibiting the presence of oxidative stress induced by APAP toxicity and the best result for protection was seen with the use of silymarin. Conclusions: The measured liver function tests may suggest an augmented hepatoprotection of the combination preparation than when compared individually.

[Acute renal failure in a healthy 19-year-old woman after intake of 7 g of paracetamol]

In this case report, a 19-year-old woman was admitted with delayed acute renal failure due to a paracetamol intake of 7 g. No liver damage was present, and the renal function recovered spontaneously after a few weeks. Paracetamol is the most common cause of medical induced overdose or death. It is well known, that poisoning from paracetamol may cause liver damage, but the risk of renal toxicity is known to a lesser extent. Acute renal failure due to paracetamol overdose may easily be missed due to the delayed manifestation.

The Relationship Between Circulating Acetaminophen-Protein Adduct Concentrations and Alanine Aminotransferase Activities in Patients With and Without Acetaminophen Overdose and Toxicity

INTRODUCTION

Measurement of serum acetaminophen-protein adducts (APAP-CYS) has been suggested to support or refute a diagnosis of acetaminophen (APAP)-induced hepatotoxicity when ingestion histories are unreliable or unavailable and when circulating APAP concentrations are low or undetectable. Non-APAP overdose patients commonly have used APAP products in non-toxic quantities and, thus, will have measurable APAP-CYS concentrations, even when hepatic injury results from other causes, such as ischemic hepatitis. The relationship between alanine aminotransferase (ALT) activity and APAP-CYS concentration might assist in distinguishing between toxic and non-toxic APAP doses in patients suspected of drug overdose.

METHODS

We measured serial levels of serum APAP-CYS and ALT activities in 500 overdose patients in whom APAP toxicity was suspected on inpatient admission, but who were then classified at time of discharge and before results of APAP-CYS concentrations were available into three groups: 1) definite APAP group; 2) definitely not APAP group; and 3) indeterminate group. Subjects in the definite and definitely not APAP groups were selected in whom a plasma ALT activity was measured within ± 4 h of a serum APAP-CYS concentration. Regressions with correlation coefficients between APAP-CYS and ALT were calculated for repeat measures in the 335 subjects (908 blood samples) in the definite APAP group and 79 subjects (231 samples) in the definitely not APAP group, with an emphasis on APAP-CYS concentrations and calculation of 95% prediction intervals when ALT was ≥ 1000 IU/L.

RESULTS

A strong correlation was found between APAP-CYS and ALT in the definite APAP group over all ALT activities (r = 0.93, p < 0.001; N = 335), and when ALT was > 1000 IU/L (r = 0.82, p < 0.001, N = 144). In the 79 definitely not APAP subjects, no significant correlation was found when ALT exceeded 1000 IU/L (r = 0.04; p = 0.84, N = 32). All subjects in the definitely not APAP group displayed APAP-CYS concentrations < 3 μM. In definitely not APAP subjects, the great majority of APAP-CYS levels were below the 95% prediction interval for APAP-CYS concentrations in definite APAP group subjects when ALT was ≥ 1000 IU/L. However, some definitely not APAP group subjects who had ingested non-toxic doses of APAP displayed APAP-CYS concentrations as high as 2.8 μM in the face of ALT elevation from ischemic hepatitis.

CONCLUSION

The interpretation of serum APAP-CYS concentrations must always be made in light of detailed clinical information and the population being tested, especially because of some overlap in APAP-CYS levels in subjects with and without APAP toxicity.

First aid interventions by laypeople for acute oral poisoning

BACKGROUND

Oral poisoning is a major cause of mortality and disability worldwide, with estimates of over 100,000 deaths due to unintentional poisoning each year and an overrepresentation of children below five years of age. Any effective intervention that laypeople can apply to limit or delay uptake or to evacuate, dilute or neutralize the poison before professional help arrives may limit toxicity and save lives.

OBJECTIVES

To assess the effects of pre-hospital interventions (alone or in combination) for treating acute oral poisoning, available to and feasible for laypeople before the arrival of professional help.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL, ISI Web of Science, International Pharmaceutical Abstracts, and three clinical trials registries to 11 May 2017, and we also carried out reference checking and citation searching.

SELECTION CRITERIA

We included randomized controlled trials comparing interventions (alone or in combination) that are feasible in a pre-hospital setting for treating acute oral poisoning patients, including but potentially not limited to activated charcoal (AC), emetics, cathartics, diluents, neutralizing agents and body positioning.

DATA COLLECTION AND ANALYSIS

Two reviewers independently performed study selection, data collection and assessment. Primary outcomes of this review were incidence of mortality and adverse events, plus incidence and severity of symptoms of poisoning. Secondary outcomes were duration of symptoms of poisoning, drug absorption, and incidence of hospitalization and ICU admission.

MAIN RESULTS

We included 24 trials involving 7099 participants. Using the Cochrane 'Risk of bias' tool, we assessed no study as being at low risk of bias for all domains. Many studies were poorly reported, so the risk of selection and detection biases were often unclear. Most studies reported important outcomes incompletely, and we judged them to be at high risk of reporting bias.All but one study enrolled oral poisoning patients in an emergency department; the remaining study was conducted in a pre-hospital setting. Fourteen studies included multiple toxic syndromes or did not specify, while the other studies specifically investigated paracetamol (2 studies), carbamazepine (2 studies), tricyclic antidepressant (2 studies), yellow oleander (2 studies), benzodiazepine (1 study), or toxic berry intoxication (1 study). Eighteen trials investigated the effects of activated charcoal (AC), administered as a single dose (SDAC) or in multiple doses (MDAC), alone or in combination with other first aid interventions (a cathartic) and/or hospital treatments. Six studies investigated syrup of ipecac plus other first aid interventions (SDAC + cathartic) versus ipecac alone. The collected evidence was mostly of low to very low certainty, often downgraded for indirectness, risk of bias or imprecision due to low numbers of events.First aid interventions that limit or delay the absorption of the poison in the bodyWe are uncertain about the effect of SDAC compared to no intervention on the incidence of adverse events in general (zero events in both treatment groups; 1 study, 451 participants) or vomiting specifically (Peto odds ratio (OR) 4.17, 95% confidence interval (CI) 0.30 to 57.26, 1 study, 25 participants), ICU admission (Peto OR 7.77, 95% CI 0.15 to 391.93, 1 study, 451 participants) and clinical deterioration (zero events in both treatment groups; 1 study, 451 participants) in participants with mixed types or paracetamol poisoning, as all evidence for these outcomes was of very low certainty. No studies assessed SDAC for mortality, duration of symptoms, drug absorption or hospitalization.Only one study compared SDAC to syrup of ipecac in participants with mixed types of poisoning, providing very low-certainty evidence. Therefore we are uncertain about the effects on Glasgow Coma Scale scores (mean difference (MD) -0.15, 95% CI -0.43 to 0.13, 1 study, 34 participants) or incidence of adverse events (risk ratio (RR) 1.24, 95% CI 0.26 to 5.83, 1 study, 34 participants). No information was available concerning mortality, duration of symptoms, drug absorption, hospitalization or ICU admission.This review also considered the added value of SDAC or MDAC to hospital interventions, which mostly included gastric lavage. No included studies investigated the use of body positioning in oral poisoning patients.First aid interventions that evacuate the poison from the gastrointestinal tractWe found one study comparing ipecac versus no intervention in toxic berry ingestion in a pre-hospital setting. Low-certainty evidence suggests there may be an increase in the incidence of adverse events, but the study did not report incidence of mortality, incidence or duration of symptoms of poisoning, drug absorption, hospitalization or ICU admission (103 participants).In addition, we also considered the added value of syrup of ipecac to SDAC plus a cathartic and the added value of a cathartic to SDAC.No studies used cathartics as an individual intervention.First aid interventions that neutralize or dilute the poison No included studies investigated the neutralization or dilution of the poison in oral poisoning patients.The review also considered combinations of different first aid interventions.

AUTHORS' CONCLUSIONS

The studies included in this review provided mostly low- or very low-certainty evidence about the use of first aid interventions for acute oral poisoning. A key limitation was the fact that only one included study actually took place in a pre-hospital setting, which undermines our confidence in the applicability of these results to this setting. Thus, the amount of evidence collected was insufficient to draw any conclusions.

Efficient diagnosis and treatment of acute paracetamol poisoning: cost-effectiveness analysis of approaches based on a hospital toxicovigilance program

OBJECTIVES

To evaluate 5 diagnostic-therapeutic strategies for suspected acute paracetamol poisoning in terms of cost-effectiveness in a tertiary university hospital with an active, validated poisoning surveillance program (SAT-HULP).

MATERIAL AND METHODS

Cost-effectiveness analysis of the 5 diagnostic-therapeutic alternatives considered when attending patients with suspected paracetamol poisoning. The alternatives were chosen by means of a decision tree. We studied patients detected by the SAT-HULP program between April 1, 2011, and January 31, 2015. The diagnostic-therapeutic alternatives were as follows: 1) systematic treatment of all patients with N-acetylcysteine (NAC), 2) NAC treatment according to the reported dose; 3) NAC treatment according to a Rümack-Matthew nomogram; 4) NAC treatment according to urine test results confirmed by a blood test, and 5) treatment according to elimination half-life calculation. Probability data were obtained from the SAT-HULP program and validation studies corresponding to the diagnostic tests. Deterministic and probabilistic sensitivity analyses were performed.

RESULTS

The approaches that were most cost-effective were those guided by reported doses and nomograms. The incremental cost-effectiveness of treatment according to reported dose was €5985.37. The sensitivity analysis showed that the model was highly dependent on variations in the main variables; the probabilistic sensitivity analysis indicated an incremental cost-effectiveness of €25 111.06 (SD, €1 534 420.16; range, €42 136.03-€92 358.75) between the first approach (treat all cases) and last (calculate elimination half-life); half-life calculation was the more efficient.

CONCLUSION

Treating according to nomogram was the most efficient diagnostic-therapeutic approach to treating paracetamol poisoning in our hospital. However, when the prevalence of paracetamol poisoning is higher and uncertainty is greater, it would be more efficient to treat based on calculating the half-life.

DNA Damage Response Regulates Initiation of Liver Regeneration Following Acetaminophen Overdose

Acetaminophen (APAP) overdose is the leading cause of acute liver failure (ALF) with limited treatment options. It is known that liver regeneration following APAP-induced ALF is a deciding factor in the final outcome. Previous studies from our laboratory using an incremental dose model involving a regenerating (300 mg/kg, APAP300) and a nonregenerating (600 mg/kg, APAP600) dose of APAP in mice have revealed several proregenerative pathways that regulate regeneration after APAP overdose. Here we report that DNA damage and repair mechanisms regulate initiation of liver regeneration following APAP overdose. Mice treated with nonregenerating APAP600 dose showed prolonged expression of pH2AX, a marker of the DNA double-strand break (DSB), compared with APAP300. In regenerating APAP300 dose-treated mice, H2AX was rapidly dephosphorylated at Tyr142, indicating timely DNA repair. Expression of several DNA repair proteins was substantially lower with APAP600. Poly(ADP) ribose polymerase (PARP) activation, involved in DNA repair, was significantly higher in the APAP300 group compared to the APAP600 group. Activation of p53, the major cell cycle checkpoint protein, was significantly higher with APAP600 as demonstrated by substantially higher expression of its target genes. Taken together, these data show that massive DNA DSB occurs in high-dose APAP toxicity, and lack of prompt DSB repair after APAP overdose leads to prolonged growth arrest and proliferative senescence, resulting in inhibited liver regeneration.

Plasminogen Activator Inhibitor-1 Reduces Tissue-Type Plasminogen Activator-Dependent Fibrinolysis and Intrahepatic Hemorrhage in Experimental Acetaminophen Overdose

Acetaminophen (APAP)-induced liver injury in mice is associated with activation of the coagulation cascade and deposition of fibrin in liver. Plasminogen activator inhibitor-1 (PAI-1) is an important physiological inhibitor of tissue-type plasminogen activator (tPA) and plays a critical role in fibrinolysis. PAI-1 expression is increased in both experimental APAP-induced liver injury and patients with acute liver failure. Prior studies have shown that PAI-1 prevents intrahepatic hemorrhage and mortality after APAP challenge, but the downstream mechanisms are not clear. We tested the hypothesis that PAI-1 limits liver-related morbidity after APAP challenge by reducing tPA-dependent fibrinolysis. Compared with APAP-challenged (300 mg/kg) wild-type mice, hepatic deposition of cross-linked fibrin was reduced, with intrahepatic congestion and hemorrhage increased in PAI-1-deficient mice 24 hours after APAP overdose. Administration of recombinant wild-type human PAI-1 reduced intrahepatic hemorrhage 24 hours after APAP challenge in PAI-1-/- mice, whereas a mutant PAI-1 lacking antiprotease function had no effect. Of interest, tPA deficiency alone did not affect APAP-induced liver damage. In contrast, fibrinolysis, intrahepatic congestion and hemorrhage, and mortality driven by PAI-1 deficiency were reduced in APAP-treated tPA-/-/PAI-1-/- double-knockout mice. The results identify PAI-1 as a critical regulator of intrahepatic fibrinolysis in experimental liver injury. Moreover, the results suggest that the balance between PAI-1 and tPA activity is an important determinant of liver pathology after APAP overdose.

Parasuicide in Central London 1984-1988

Experience of a central London unit dedicated to the care of patients following parasuicide between 1984 and 1988 is reviewed. There were 1160 admissions, which accounted for 11% of all acute adult medical admissions. The female to male ratio was 1.3, with a peak rate for females below 25 years and for males between 20 and 35. Unemployment was found to be a risk factor for parasuicide in men. Benzodiazepines were the most frequently used drug in parasuicide (35%), followed by paracetamol (13%) and aspirin (9%).

Interventions for paracetamol (acetaminophen) overdose

BACKGROUND

Paracetamol (acetaminophen) is the most widely used non-prescription analgesic in the world. Paracetamol is commonly taken in overdose either deliberately or unintentionally. In high-income countries, paracetamol toxicity is a common cause of acute liver injury. There are various interventions to treat paracetamol poisoning, depending on the clinical status of the person. These interventions include inhibiting the absorption of paracetamol from the gastrointestinal tract (decontamination), removal of paracetamol from the vascular system, and antidotes to prevent the formation of, or to detoxify, metabolites.

OBJECTIVES

To assess the benefits and harms of interventions for paracetamol overdosage irrespective of the cause of the overdose.

SEARCH METHODS

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register (January 2017), CENTRAL (2016, Issue 11), MEDLINE (1946 to January 2017), Embase (1974 to January 2017), and Science Citation Index Expanded (1900 to January 2017). We also searched the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov database (US National Institute of Health) for any ongoing or completed trials (January 2017). We examined the reference lists of relevant papers identified by the search and other published reviews.

SELECTION CRITERIA

Randomised clinical trials assessing benefits and harms of interventions in people who have ingested a paracetamol overdose. The interventions could have been gastric lavage, ipecacuanha, or activated charcoal, or various extracorporeal treatments, or antidotes. The interventions could have been compared with placebo, no intervention, or to each other in differing regimens.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from the included trials. We used fixed-effect and random-effects Peto odds ratios (OR) with 95% confidence intervals (CI) for analysis of the review outcomes. We used the Cochrane 'Risk of bias' tool to assess the risks of bias (i.e. systematic errors leading to overestimation of benefits and underestimation of harms). We used Trial Sequential Analysis to control risks of random errors (i.e. play of chance) and GRADE to assess the quality of the evidence and constructed 'Summary of findings' tables using GRADE software.

MAIN RESULTS

We identified 11 randomised clinical trials (of which one acetylcysteine trial was abandoned due to low numbers recruited), assessing several different interventions in 700 participants. The variety of interventions studied included decontamination, extracorporeal measures, and antidotes to detoxify paracetamol's toxic metabolite; which included methionine, cysteamine, dimercaprol, or acetylcysteine. There were no randomised clinical trials of agents that inhibit cytochrome P-450 to decrease the activation of the toxic metabolite N-acetyl-p-benzoquinone imine.Of the 11 trials, only two had two common outcomes, and hence, we could only meta-analyse two comparisons. Each of the remaining comparisons included outcome data from one trial only and hence their results are presented as described in the trials. All trial analyses lack power to access efficacy. Furthermore, all the trials were at high risk of bias. Accordingly, the quality of evidence was low or very low for all comparisons. Interventions that prevent absorption, such as gastric lavage, ipecacuanha, or activated charcoal were compared with placebo or no intervention and with each other in one four-armed randomised clinical trial involving 60 participants with an uncertain randomisation procedure and hence very low quality. The trial presented results on lowering plasma paracetamol levels. Activated charcoal seemed to reduce the absorption of paracetamol, but the clinical benefits were unclear. Activated charcoal seemed to have the best risk:benefit ratio among gastric lavage, ipecacuanha, or supportive treatment if given within four hours of ingestion. There seemed to be no difference between gastric lavage and ipecacuanha, but gastric lavage and ipecacuanha seemed more effective than no treatment (very low quality of evidence). Extracorporeal interventions included charcoal haemoperfusion compared with conventional treatment (supportive care including gastric lavage, intravenous fluids, and fresh frozen plasma) in one trial with 16 participants. The mean cumulative amount of paracetamol removed was 1.4 g. One participant from the haemoperfusion group who had ingested 135 g of paracetamol, died. There were no deaths in the conventional treatment group. Accordingly, we found no benefit of charcoal haemoperfusion (very low quality of evidence). Acetylcysteine appeared superior to placebo and had fewer adverse effects when compared with dimercaprol or cysteamine. Acetylcysteine superiority to methionine was unproven. One small trial (low quality evidence) found that acetylcysteine may reduce mortality in people with fulminant hepatic failure (Peto OR 0.29, 95% CI 0.09 to 0.94). The most recent randomised clinical trials studied different acetylcysteine regimens, with the primary outcome being adverse events. It was unclear which acetylcysteine treatment protocol offered the best efficacy, as most trials were underpowered to look at this outcome. One trial showed that a modified 12-hour acetylcysteine regimen with a two-hour acetylcysteine 100 mg/kg bodyweight loading dose was associated with significantly fewer adverse reactions compared with the traditional three-bag 20.25-hour regimen (low quality of evidence). All Trial Sequential Analyses showed lack of sufficient power. Children were not included in the majority of trials. Hence, the evidence pertains only to adults.

AUTHORS' CONCLUSIONS

These results highlight the paucity of randomised clinical trials comparing different interventions for paracetamol overdose and their routes of administration and the low or very low level quality of the evidence that is available. Evidence from a single trial found activated charcoal seemed the best choice to reduce absorption of paracetamol. Acetylcysteine should be given to people at risk of toxicity including people presenting with liver failure. Further randomised clinical trials with low risk of bias and adequate number of participants are required to determine which regimen results in the fewest adverse effects with the best efficacy. Current management of paracetamol poisoning worldwide involves the administration of intravenous or oral acetylcysteine which is based mainly on observational studies. Results from these observational studies indicate that treatment with acetylcysteine seems to result in a decrease in morbidity and mortality, However, further evidence from randomised clinical trials comparing different treatments are needed.

Risk stratification after paracetamol overdose using mechanistic biomarkers: results from two prospective cohort studies

BACKGROUND

Paracetamol overdose is common but patient stratification is suboptimal. We investigated the usefulness of new biomarkers that have either enhanced liver specificity (microRNA-122 [miR-122]) or provide mechanistic insights (keratin-18 [K18], high mobility group box-1 [HMGB1], and glutamate dehydrogenase [GLDH]). The use of these biomarkers could help stratify patients for their risk of liver injury at hospital presentation.

METHODS

Using data from two prospective cohort studies, we assessed the potential for biomarkers to stratify patients who overdose with paracetamol. We completed two independent prospective studies: a derivation study (MAPP) in eight UK hospitals and a validation study (BIOPAR) in ten UK hospitals. Patients in both cohorts were adults (≥18 years in England, ≥16 years in Scotland), were diagnosed with paracetamol overdose, and gave written informed consent. Patients who needed intravenous acetylcysteine treatment for paracetamol overdose had circulating biomarkers measured at hospital presentation. The primary endpoint was acute liver injury indicating need for continued acetylcysteine treatment beyond the standard course (alanine aminotransferase [ALT] activity >100 U/L). Receiver operating characteristic (ROC) curves, category-free net reclassification index (cfNRI), and integrated discrimination index (IDI) were applied to assess endpoint prediction.

FINDINGS

Between June 2, 2010, and May 29, 2014, 1187 patients who required acetylcysteine treatment for paracetamol overdose were recruited (985 in the MAPP cohort; 202 in the BIOPAR cohort). In the derivation and validation cohorts, acute liver injury was predicted at hospital presentation by miR-122 (derivation cohort ROC-area under the curve [AUC] 0·97 [95% CI 0·95-0·98]), HMGB1 (0·95 [0·93-0·98]), and full-length K18 (0·95 [0·92-0·97]). Results were similar in the validation cohort (miR-122 AUC 0·97 [95% CI 0·95-0·99], HMGB1 0·98 [0·96-0·99], and full-length K18 0·93 [0·86-0·99]). A combined model of miR-122, HMGB1, and K18 predicted acute liver injury better than ALT alone (cfNRI 1·95 [95% CI 1·87-2·03], p<0·0001 in the MAPP cohort; 1·54 [1·08-2·00], p<0·0001 in the BIOPAR cohort).

INTERPRETATION

Personalised treatment pathways could be developed by use of miR-122, HMGB1, and full-length K18 at hospital presentation for patient stratification. This prospective study supports their use for hepatic safety assessment of new medicines.

FUNDING

Edinburgh and Lothians Health Foundation, UK Medical Research Council.

Acetaminophen (APAP) hepatotoxicity-Isn't it time for APAP to go away?

Acetaminophen (APAP) is the most commonly used drug for the treatment of pain and fever around the world. At the same time, APAP can cause dose-related hepatocellular necrosis, responsible for nearly 500 deaths annually in the United States (US) alone, as well as 100,000 calls to US Poison Control Centers, 50,000 emergency room visits and 10,000 hospitalisations per year. As an over-the-counter and prescription product (with opioids), APAP toxicity dwarfs all other prescription drugs as a cause of acute liver failure in the US and Europe, but it is not regulated in any significant way. In this review the ongoing controversy surrounding the proper role for this ubiquitous pain reliever: its history, pathogenesis, clinical challenges in recognition and management, and current regulatory status are highlighted. A new solution to a 50-year-old problem is proposed.

Supra-Therapeutic Oral Paracetamol Overdose in Adults: An Update for the Dental Team

Paracetamol (acetaminophen) is a commonly used analgesic; its 'over the counter' availability, low cost and popularity amongst patients often make it the first choice for dental pain. It is in this that its potential toxicity, made more complicated by the ever extending range of paracetamol-containing products, make the understanding of this medication key to the safe management of patients presenting to surgery with dental pain. Clinical relevance: The purpose of this article is to supply dental practitioners with the knowledge to manage patients who present having taken an oral supra-therapeutic paracetamol overdose. Consideration is given to those patients who can be treated safely in primary care and to those who require transfer to Accident and Emergency (A&E).

Effects of rosmarinic acid on acetaminophen-induced hepatotoxicity in male Wistar rats

CONTEXT

Drug-induced liver injury is a significant worldwide clinical problem. Rosmarinic acid (RA), a natural phenol, has antioxidant effects.

OBJECTIVE

The effects of RA against acetaminophen (N-acetyl-p-amino-phenol (APAP))-induced oxidative damage and hepatotoxicity in rats were investigated.

MATERIALS AND METHODS

Male Wistar rats were pretreated with RA (10, 50 and 100 mg/kg, i.g.) for one week. On day 7, rats received APAP (500 mg/kg, i.p.). Then aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin, total protein, malondialdehyde (MDA), glutathione (GSH), total antioxidant capacity (TAC), glutathione S-transferase (GST), cytochrome CYP450 and histopathological changes were determined.

RESULTS

APAP-induced oxidative stress in liver by a significant increase in the level of MDA (7.6 ± 0.21 nmol/mg) as well as a decrease in the contents of TAC (1.75 ± 0.14 μmol/g), GSH (1.9 ± 0.22 μmol/g) and GST) 3.2 ± 0.28 U/mg). RA treatment decreased MDA (4.32 ± 0.35 nmol/mg) but increased the contents of TAC (3.51 ± 0.34 μmol/g), GSH (3.42 ± 0.16 μmol/g) and GST (5.71 ± 0.71 μmol/g) in APAP group. RA 100 mg/kg decreased ALT (91.5 ± 1.5 U/L), AST (169 ± 8.8 U/L) and CYP450 (3 ± 0.2 nmol/min/mg) in APAP group. Histologically RA attenuated hepatic damage by decreasing necrosis, inflammation, and haemorrhage in liver sections of APAP group.

DISCUSSION AND CONCLUSIONS

This is the first report that oral administration of RA dose-dependently elicited significant hepatoprotective effects in rats through inhibition of hepatic CYP2E1 activity and lipid peroxidation. RA-protected hepatic GSH and GST reserves and total tissue antioxidant capacity.

[Access to rapid laboratory analytical services in cases of acute poisoning provides better and safer patient care]

Access to rapid laboratory analytical services in cases of acute poisoning provides better and safer patient care The Swedish Poisons Information Centre, a nationwide 24/7 service to healthcare providers and the public, answers many questions about serious cases of acute poisoning. In some of these, prompt and proper treatment recommendations can be crucial for the clinical outcome. In cases where self-reported information is missing or considered unreliable, more emphasis is placed on the clinical symptoms and results of toxicological analyses. However, rapid access to toxicological analysis for the most common set of poisoning agents varies between hospitals and laboratories. A priority list of toxic agents for which improved analytical techniques could offer a more widespread availability and rapid access to clinically important test results is presented.

EASL Clinical Practical Guidelines on the management of acute (fulminant) liver failure

The term acute liver failure (ALF) is frequently applied as a generic expression to describe patients presenting with or developing an acute episode of liver dysfunction. In the context of hepatological practice, however, ALF refers to a highly specific and rare syndrome, characterised by an acute abnormality of liver blood tests in an individual without underlying chronic liver disease. The disease process is associated with development of a coagulopathy of liver aetiology, and clinically apparent altered level of consciousness due to hepatic encephalopathy. Several important measures are immediately necessary when the patient presents for medical attention. These, as well as additional clinical procedures will be the subject of these clinical practice guidelines.

Acetaminophen overdoses, active component, U.S. Armed Forces, 2006-2015

Acetaminophen, a drug commonly used to relieve pain and fever, is generally safe and effective when used as directed. However, acetaminophen overdose can cause serious adverse events, including liver damage and death. From 2006 through 2015, a total of 2,588 cases of acetaminophen overdose were identified in active component military members. Rates of acetaminophen overdose declined during this 10-year surveillance period, from 2.2 cases per 10,000 person-years (p-yrs) in 2006 to 1.2 cases per 10,000 p-yrs in 2015. Rates of overdose were higher among females, members of the Army, and service members younger than 25 years of age. Despite the apparent decline in acetaminophen overdose in the active component, continued surveillance is warranted to monitor this trend.

Hypokalaemia following paracetamol overdose in two teenage girls

We report on two teenage girls presenting following significant paracetamol overdoses (>28 g paracetamol). Both presented within 4 h of the overdose and both were treated with N-acetylcysteine, in accordance with the National Poisons Information Service protocol. Within 8 h of presentation both had developed significant hypokalaemia with serum potassium concentrations <3.0 mmol/L and were treated with intravenous potassium chloride. Potassium concentrations returned to within reference limits (>3.5 mmol/L) after commencing potassium chloride supplementation. An audit of potassium concentrations in 254 patients presenting with significant paracetamol overdose (paracetamol >0.5 mmol/L) admitted through four A&E departments in the West of Scotland showed a significant decline in mean serum potassium from 3.9 mmol/L on admission to 3.6 mmol/L ( P = <0.001) over the next 36 h. The mechanism for this hypokalaemia in these two individuals is unclear, however regular monitoring of potassium is advocated in such patients during their initial treatment.

Hypercoagulable State Due to Alcohol-Paracetamol Syndrome Producing Acute Limb Ischemia

The authors describe a man with alcohol-paracetamol syndrome and hepatic failure who presented with acute arterial thrombosis of the left limb. The patient has jaundice, increased serum transaminase levels, and significant coagulopathy, with elevated international normalized ratio and prolonged prothrombin time. A transient hypercoagulable state due to liver failure is documented, characterized by acquired deficiencies of antithrombin III, protein C, and protein S. Laboratory and molecular testing for inherited hypercoagulable disorders during the follow-up period is positive for increased levels of factor VIII. The patient undergoes successful thrombectomy and receives intensive symptomatic and causal treatment, resulting in complete recovery. The patient is discharged 20 days after admission on a regimen of acenocoumarol.

Non-accidental non-fatal poisonings attended by emergency ambulance crews: an observational study of data sources and epidemiology

BACKGROUND

Non-accidental non-fatal poisoning (NANFP) is associated with high risk of repeat episodes and fatality. This cross-sectional study aims to describe the data sources and epidemiology of non-fatal poisonings (NFPs) presenting to the emergency ambulance service.

METHODS

We assessed incidents of NFP across Wales from electronic ambulance call centre records and paper records completed by attending ambulance crews, December 2007 to February 2008. We descriptively analysed data completed by attending crews.

RESULTS

92 331 calls were made to the ambulance call centre, of which 3923 (4.2%) were coded as 'overdose' or 'poisoning'. During the same period, ambulance crews recorded 1827 attended NANFP incidents in those categories, of which 1287 (70.4%) had been identified in the call centre. 76.1% (1356/1782) were aged 15-44 years and 54.2% (991/1827) were female. 75.0% (1302/1753) of incidents occurred in areas from the lower 2 quintiles of deprivation in Wales. Substance taken was reported in 90% of cases (n=1639). Multiple ingestion was common (n=886, 54.1%). Psychotropic was the most frequently taken group of substances (n=585, 32.0%) and paracetamol (n=484, 26.5%) was the most frequently taken substance prehospital. Almost half of patients had taken alcohol alongside other substances (n=844, 46.2%). Naloxone was the most frequently administered treatment (n=137, 7.5%). Only 142/1827 (7.8%) patients were not transported to hospital, of whom 4 were recorded to have been given naloxone.

CONCLUSIONS

We report new data on the epidemiology of NFP across substance types at national level, highlighting deficiencies in information systems and high levels of multiple ingestion. In order to develop policy and practice for this patient group prehospital and further along the care pathway, information systems need to be developed to allow accurate routine monitoring of volume, presentation and outcomes.

Double-peaked Acetaminophen Concentration Secondary to Intestinal Trauma

BackgroundReduced gastrointestinal motility can alter the toxicokinetics of acetaminophen poisoning. We report a case of altered acetaminophen toxicokinetics due to delayed gastrointestinal absorption, likely secondary to intestinal trauma/surgery.  Case ReportA 37-year-old woman ingested an unknown amount of acetaminophen and ethanol then stabbed herself in the abdomen. The initial acetaminophen was 1,285.9 μmol/L and the time of ingestion was not known. Intravenous acetylcysteine protocol was started. She developed an ileus post-surgery for the stab wounds. At 31 hours post-presentation, the acetaminophen returned undetectable, and the transaminases were normal. After the resolution of the ileus, repeated acetaminophen peaked at 363.3 μmol/L 52 hours post-admission. At 76 hours post-admission, the acetaminophen was undetectable, and transaminases and coagulation parameters were normal. ConclusionsReduction in gastrointestinal motility secondary to trauma and/or surgery must be considered when determining when to initiate or discontinue treatment as well as how long to monitor acetaminophen concentrations.

Prothrombin time prolongation in paracetamol poisoning: a relevant marker of hepatic failure?

The association between paracetamol overdose and prolonged prothrombin time due to hepatic failure is well recognized. However, little is known of the possibility that paracetamol overdose can prolong the prothrombin time without overt hepatic failure. The few data from the literature suggest this is either due to a reduction in the functional levels of the vitamin K-dependent clotting factors by elevated doses of paracetamol, or a consequence of the administration of the antidote N-acetylcystein. The three reported cases provide further evidence that paracetamol overdose can be associated with a prolongation in the prothrombin time without overt hepatic failure. Even though the prothrombin time provides useful prognosis information, decisions regarding the management of these patients should not solely be based on this endpoint to avoid misinterpretation of the accuracy and the severity of liver failure.