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.