Activated charcoal reduces the need for N-acetylcysteine treatment after acetaminophen (paracetamol) overdose

The Insidious Enemy of the Liver: The Situation in Childhood Acetaminophen Poisoning and Early N-AC Treatment

METHODS

This study was designed as a cross-sectional, observational, retrospective study. The variables of the study were paracetamol overdose, demographic information, poisoning mechanisms, clinical, laboratory findings, and clinical progression of the cases. The cases compared in whom treatment was initiated within the first 8 hours after poisoning and those in whom it was not. χ 2 , t test, and logistic regression analyses were conducted at appropriate facilities.

RESULTS

Three hundred forty-eight cases were included in the study. N-AC treatment was initiated within the first 8 hours after poisoning in 322 cases (92.5%), and 26 cases received N-AC treatment after 8 hours after poisoning. Liver toxicity developed in 6 cases (1.7%), and indications for liver transplantation were met in 36 cases (10.3%). Among the 26 cases for which treatment was not initiated within the first 8 hours, 18 cases (69.2%) had indications for liver transplantation ( P < 0.01). It was found that N-AC within the first 8 hours reduced the risk by 43 times ( P = 0.02) and being older than 6 years, being admitted to the intensive care unit, and having alanine aminotransferase values above 1000 U/L increased the risk significantly ( P = 0.009, P = 0.005, P < 0.001). When a receiver operating characteristic curve was plotted for the 4th-hour blood acetaminophen level to predict liver transplantation, a value of 684.5 μg/mL emerged with 89% sensitivity and 93% specificity (area under the curve, 0.951).

CONCLUSIONS

As a result, this study demonstrates the protective effect of early-initiated N-AC therapy on liver toxicity in pediatric acetaminophen poisoning cases. It also highlights a significant impact of gastrointestinal decontamination methods.

Patterns and outcomes of paracetamol poisoning management in Hamad Medical Corporation, Qatar: A retrospective cohort study

We aimed to investigate the characteristics and clinical outcomes of paracetamol poisoning and paracetamol overdose in Qatar. This retrospective cohort study included patients admitted to the emergency department (ED). We included patients who presented with excessive paracetamol ingestion, between December 2018 and September 2019. The primary outcomes were describing the characteristics and outcomes of paracetamol overdose (from a suicidal overdose or accidental overdose, dose ≤ 150 mg/kg, when serum levels of <60 mmol/L) or dose ingested (≤75 mg/kg) with staggered ingestion poisoning due to suicidal attempt or accidental attempt, defined as the dose ingested (>150 mg/kg), acute ingestion, nomogram level more than the treatment line, or dose ingested (>75 mg/kg) with staggered ingestion, and assessing the management of excessive paracetamol ingestion. Secondary outcomes included evaluation of the time difference between ingestion and time of administration, hospitalization, and adverse drug events. Significant differences were detected between patients who presented with paracetamol overdose and those who presented with paracetamol toxicity. A total of 69 patients were analyzed, of whom 43 received paracetamol overdose (mean age 27.5 ± 11.1 years) and 26 had paracetamol poisoning (mean age 25 ± 6.22 years). Paracetamol poisoning was identified in 26% of the patients with a 24.3% history of psychiatric illness, compared to 18.6% with paracetamol overdose. More patients presented with paracetamol toxicity in the time between ingestion and obtaining serum levels compared to the overdose group. A significantly longer length of hospitalization was observed in the toxicity group. A significantly higher number of patients in the toxicity group received N-acetylcysteine (NAC). More hypotension and rashes were observed among those who received NAC in the toxicity group. Patients presenting to the ED due to paracetamol toxicity are not uncommon, and most cases occur in young adults, and few in patients with a history of psychiatric illness, suggesting that preventive approaches are highly required.

Acute Liver Failure Guidelines

Acute liver failure (ALF) is a rare, acute, potentially reversible condition resulting in severe liver impairment and rapid clinical deterioration in patients without preexisting liver disease. Due to the rarity of this condition, published studies are limited by the use of retrospective or prospective cohorts and lack of randomized controlled trials. Current guidelines represent the suggested approach to the identification, treatment, and management of ALF and represent the official practice recommendations of the American College of Gastroenterology. The scientific evidence was reviewed using the Grading of Recommendations, Assessment, Development and Evaluation process to develop recommendations. When no robust evidence was available, expert opinions were summarized using Key Concepts. Considering the variety of clinical presentations of ALF, individualization of care should be applied in specific clinical scenarios.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

The Unethical Use of Paracetamol As a Food Tenderizer in Four Selected African Countries: A Major Public Health Concern?

Paracetamol poisoning is the commonest cause of acute liver injury. Therefore, the unethical use of paracetamol as a food tenderizer poses a threat to human health. Although this is a common practice in Ghana, Uganda, Nigeria, and Kenya, there are few or no scientific records on the use of paracetamol as a food tenderizer and its deleterious effects, thus making it difficult to regulate this practice. This review aims to fully collate and present a systematic overview of the literature on the use of paracetamol as a food tenderizer in these countries, the potentially harmful effects posed by the practice, and measures in place to curb the situation. Additionally, this review aims to reveal the scientific gaps and areas requiring more research, thus providing a reference for further research to regulate this unscrupulous practice. From our extensive review of the literature, the high cost of fuel used in cooking and longer cooking times are the main reasons for the inappropriate use of paracetamol as a food tenderizer. Also, this review concludes that little has been done to create public awareness of this unethical practice. Furthermore, few ways to monitor, control and regulate this practice have been proposed.

Estimates of Paracetamol Poisoning in Brazil: Analysis of Official Records From 1990s to 2020

Objective: To assess the cases of paracetamol poisoning in Brazil.

METHODS

Analysis of official records of deaths between 1996 and 2019 from the Brazil Mortality Information System (SIM), admissions between 2008 and 2020 from the Hospital Information System (SIH), and cases of poisoning between 2017 and 2020 in health services, reported to the Brazilian Notifiable Diseases Surveillance System (SINAN). In SIM and SIH, records with ICD-10 were included: F55, T39, X40, X60, and Y10. In SINAN, commercial products containing paracetamol were identified. Records were stratified by age, sex, and intentionality. Mean and standard error were calculated for each stratum based on the annual data, by federation unit. Poisoning reports by 1,000,000 inhabitants were calculated from each state and compared to the national average.

RESULTS

In total, 492 deaths, 5,666 hospital admissions, and 17,031 cases of paracetamol poisoning were recorded in the period. Deaths occurred mostly among adults (71.3% ± 3.0) and in suicide attempts (37.3% ± 2.7). Hospital admissions were more frequent in adults (69.7% ± 1.4), women (57.1% ± 2.5), and unintentional poisoning (80.2% ± 4.2). Poisoning reports was more also frequent among adults (71.4% ± 1.2), women (74.2% ± 0.6), and due to accidents (79.6% ± 1.8). The South and Southeast regions of the country presented the highest frequencies in all outcomes, above the national average.

CONCLUSION

Paracetamol exposure is a concern for preventable poisonings, hospital admissions and deaths. More accurate data about paracetamol poisoning are required to support surveillance actions and the development of mechanisms to reduce poisoning, particularly related to adults, women and suicide attempts.

Systematic review on the use of activated charcoal for gastrointestinal decontamination following acute oral overdose

INTRODUCTION

The use of activated charcoal in poisoning remains both a pillar of modern toxicology and a source of debate. Following the publication of the joint position statements on the use of single-dose and multiple-dose activated charcoal by the American Academy of Clinical Toxicology and the European Association of Poison Centres and Clinical Toxicologists, the routine use of activated charcoal declined. Over subsequent years, many new pharmaceuticals became available in modified or alternative-release formulations and additional data on gastric emptying time in poisoning was published, challenging previous assumptions about absorption kinetics. The American Academy of Clinical Toxicology, the European Association of Poison Centres and Clinical Toxicologists and the Asia Pacific Association of Medical Toxicology founded the Clinical Toxicology Recommendations Collaborative to create a framework for evidence-based recommendations for the management of poisoned patients. The activated charcoal workgroup of the Clinical Toxicology Recommendations Collaborative was tasked with reviewing systematically the evidence pertaining to the use of activated charcoal in poisoning in order to update the previous recommendations.

OBJECTIVES

The main objective was: Does oral activated charcoal given to adults or children prevent toxicity or improve clinical outcome and survival of poisoned patients compared to those who do not receive charcoal?  Secondary objectives were to evaluate pharmacokinetic outcomes, the role of cathartics, and adverse events to charcoal administration. This systematic review summarizes the available evidence on the efficacy of activated charcoal.

METHODS

A medical librarian created a systematic search strategy for Medline (Ovid), subsequently translated for Embase (via Ovid), CINAHL (via EBSCO), BIOSIS Previews (via Ovid), Web of Science, Scopus, and the Cochrane Library/DARE. All databases were searched from inception to December 31, 2019. There were no language limitations.  One author screened all citations identified in the search based on predefined inclusion/exclusion criteria. Excluded citations were confirmed by an additional author and remaining articles were obtained in full text and evaluated by at least two authors for inclusion. All authors cross-referenced full-text articles to identify articles missed in the searches. Data from included articles were extracted by the authors on a standardized spreadsheet and two authors used the GRADE methodology to independently assess the quality and risk of bias of each included study.

RESULTS

From 22,950 titles originally identified, the final data set consisted of 296 human studies, 118 animal studies, and 145 in vitro studies. Also included were 71 human and two animal studies that reported adverse events. The quality was judged to have a Low or Very Low GRADE in 469 (83%) of the studies. Ninety studies were judged to be of Moderate or High GRADE. The higher GRADE studies reported on the following drugs: paracetamol (acetaminophen), phenobarbital, carbamazepine, cardiac glycosides (digoxin and oleander), ethanol, iron, salicylates, theophylline, tricyclic antidepressants, and valproate. Data on newer pharmaceuticals not reviewed in the previous American Academy of Clinical Toxicology/European Association of Poison Centres and Clinical Toxicologists statements such as quetiapine, olanzapine, citalopram, and Factor Xa inhibitors were included. No studies on the optimal dosing for either single-dose or multiple-dose activated charcoal were found. In the reviewed clinical data, the time of administration of the first dose of charcoal was beyond one hour in 97% (n = 1006 individuals), beyond two hours in 36% (n = 491 individuals), and beyond 12 h in 4% (n = 43 individuals) whereas the timing of the first dose in controlled studies was within one hour of ingestion in 48% (n = 2359 individuals) and beyond two hours in 36% (n = 484) of individuals.

CONCLUSIONS

This systematic review found heterogenous data. The higher GRADE data was focused on a few select poisonings, while studies that addressed patients with unknown and or mixed ingestions were hampered by low rates of clinically meaningful toxicity or death.  Despite these limitations, they reported a benefit of activated charcoal beyond one hour in many clinical scenarios.

Safety of treating acute liver injury and failure

INTRODUCTION

Acute liver injury and progression to acute liver failure can be life-threatening conditions that require prompt careful clinical assessment and therapeutic management.

AREAS COVERED

The aim of this article is to review the safety and side effect profile of pharmacological therapies used in the treatment of acute liver injury with specific focus on hepatic toxicity. We performed an extensive literature search with the terms 'acute liver injury,' 'acute liver failure,' 'therapy,' 'safety,' 'adverse reactions' and 'drug induced liver injury.' A thorough discussion of the main drugs and devices used in patients with acute liver injury and acute liver failure, its safety profile and the management of complications associated to therapy of these conditions is presented.

EXPERT OPINION

Several pharmacological approaches are used in acute liver injury and acute liver failure in an empirical basis. Whilst steroids are frequently tried in serious drug-induced liver injury there is concern on a potential harmful effect of these agents because of the higher mortality in patients receiving the drug; hence, statistical approaches such as propensity score matching might help resolve this clinical dilemma. Likewise, properly designed clinical trials using old and new drugs for subjects with serious drug-induced liver injury are clearly needed.

The Use of Activated Charcoal to Treat Intoxications

BACKGROUND

In 2016, according to the German Federal Statistical Office, 178 425 cases of intoxication (poisoning) were treated in German hospitals. The poison control centers in the German-speaking countries gave advice in a total of 268 787 instances of poisoning in that year, and use of activated charcoal was recommended in 4.37% of cases. The application of activated charcoal plays a major role in both primary and secondary detoxification. This article serves as an overview of the mechanism of action, indications, contraindications, modes of application, and dosing of activated charcoal.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed. The opinions of experts from the poison control centers in the German-speaking countries were considered in the interpretation of the data.

RESULTS

The administration of activated charcoal is indicated to treat moderately severe to life-threatening intoxication. It should be carried out as soon as possible, within the first hour of the ingestion; timed-release preparations can be given up to 6 hours after the ingestion. An important contraindication is impaired consciousness with the danger of aspiration in a patient whose air- way has not yet been secured. Activated charcoal is ineffective or inadequately effective in cases of poisoning with acids or bases, alcohols, organic solvents, inorganic salts, or metals. The proper dosage consists of an amount that is 10 to 40 times as much as that of the intoxicating substance, or else 0.5-1 g/kg body weight in children or 50 g in adults. Repeated application is indicated for intoxications with agents that persist for a longer time in the stomach and for intoxications with timed-release drugs or drugs with a marked enterohepatic or entero-enteric circulation. The routine combination of activated charcoal with a laxative is not recommended.

CONCLUSION

Even though intoxications are common, there is still no internationally valid guideline concerning the administration of activated charcoal. A precise analysis of the risks and benefits is needed for each administration, and a poison control center should be consulted for this purpose.

Clinical Effects of Activated Charcoal Unavailability on Treatment Outcomes for Oral Drug Poisoned Patients

Background

Activated charcoal is the most frequently and widely used oral decontaminating agent in emergency departments (EDs). However, there is some debate about its clinical benefits and risks. In Korea, activated charcoal with sorbitol was unavailable as of the mid-2015, and our hospital had been unable to use it from September 2015. This study examined the differences of clinical features and outcomes of patients during the periods charcoal was and was not available.

Methods

We retrospectively reviewed the electronic medical records of patients who had visited an urban tertiary academic ED for oral drug poisoning between January 2013 and January 2017.

Results

For the charcoal-available period, 413 patients were identified and for the charcoal-unavailable period, 221. Activated charcoal was used in the treatment of 141 patients (34%) during the available period. The mortality rates during the available and unavailable periods were 1.9 and 0.9%, respectively (p = 0.507). There was also no interperiod difference in the development of aspiration pneumonia (9.9 versus 9.5%, p = 0.864), the endotracheal intubation rate (8.4 versus 7.2%, p = 0.586), and vasopressor use (5.3 versus 5.0%, p = 0.85). Intensive care unit (ICU) admission was higher in the unavailable period (5.8 versus 13.6%, p = 0.001). ICU days were lower in the unavailable period (10 [4.5-19] versus 4 [3-9], p = 0.01). Hospital admission (43.3 versus 29.9%, p = 0.001) was lower in the unavailable period.

Conclusions

In this single center study, there appeared to be no difference in mortality, intubation rates, or vasopressor use between the charcoal-available and charcoal-unavailable periods.

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.

Massive paracetamol overdose: an observational study of the effect of activated charcoal and increased acetylcysteine dose (ATOM-2)

CONTEXT

Paracetamol is commonly taken in overdose, with increasing concerns that those taking "massive" overdoses have higher rates of hepatotoxicity and may require higher doses of acetylcysteine. The objective was to describe the clinical characteristics and outcomes of "massive" (≥ 40 g) paracetamol overdoses.

METHODS

Patients were identified through the Australian Paracetamol Project, a prospective observational study through Poisons Information Centres in NSW and Queensland, over 3 and 1.5 years, respectively, and retrospectively from three clinical toxicology unit databases (over 2.5 to 20 years). Included were immediate-release paracetamol overdoses ≥ 40 g ingested over ≤ 8 h. Outcomes measured included paracetamol ratio[defined as the ratio of the first paracetamol concentration taken 4-16 h post-ingestion to the standard (150 mg/L at 4 h) nomogram line at that time] and hepatotoxicity (ALT >1000 U/L).

RESULTS

Two hundred paracetamol overdoses were analysed, reported median dose ingested was 50 g (interquartile range (IQR): 45-60 g) and median paracetamol ratio 1.9 (IQR: 1.4-2.9, n = 173). One hundred and ninety-three received acetylcysteine at median time of 6.3 h (IQR: 4-9.3 h) post-ingestion. Twenty-eight (14%) developed hepatotoxicity, including six treated within 8 h of ingestion. Activated charcoal was administered to 49(25%), at median of 2 h post-ingestion (IQR:1.5-5 h). Those receiving activated charcoal (within 4 h of ingestion), had significantly lower paracetamol ratio versus those who did not: 1.4 (n = 33, IQR: 1.1-1.6) versus 2.2 (n = 140, IQR: 1.5-3.0) (p < .0001) (paracetamol concentration measured ≥ 1 h after charcoal). Furthermore, they had lower rates of hepatotoxicity [unadjusted OR: 0.12 (95% CI: <0.001-0.91); adjusted for time to acetylcysteine OR: 0.20 (95%CI: 0.002-1.74)]. Seventy-nine had a paracetamol ratio ≥2, 43 received an increased dose of acetylcysteine in the first 21 h; most commonly a double dose in the last bag (100 to 200 mg/kg/16 h). Those receiving increased acetylcysteine had a significant decrease risk of hepatotoxicity [OR:0.27 (95% CI: 0.08-0.94)]. The OR remained similar after adjustment for time to acetylcysteine and paracetamol ratio.

CONCLUSION

Massive paracetamol overdose can result in hepatotoxicity despite early treatment. Paracetamol concentrations were markedly reduced in those receiving activated charcoal within 4 h. In those with high paracetamol concentrations, treatment with increased acetylcysteine dose within 21 h was associated with a significant reduction in hepatotoxicity.

Management of Acute Hepatotoxicity Including Medical Agents and Liver Support Systems

Drug-induced liver injury (DILI) can be predictable or idiosyncratic and has an estimated incidence of approximately 20 cases per 100,000 persons per year. DILI is a common cause of acute liver failure in the United States. No accurate tests for diagnosing DILI exist, and its diagnosis is based on exclusion of other conditions. Managing DILI includes discontinuing the suspected causative agent and in selected cases administering an antidote. Liver support systems are used for long-term support or as a bridge to transplantation and are effective for improving encephalopathy, hyperbilirubinemia, and other liver-related conditions, but whether they improve survival remains uncertain.

The 100 most influential publications in paracetamol poisoning treatment: a bibliometric analysis of human studies

BACKGROUND

Analysis of the most influential publications within paracetamol poisoning treatment can be helpful in recognizing main and novel treatment issues within the field of toxicology. The current study was performed to recognize and describe the most highly cited articles related to paracetamol poisoning treatment.

METHODS

The 100 most highly cited articles in paracetamol poisoning treatment were identified from the Scopus database in November 2015. All eligible articles were read for basic information, including total number of citations, average citations per year, authors' names, journal name, impact factors, document types and countries of authors of publications.

RESULTS

The median number of citations was 75 (interquartile range 56-137). These publications were published between 1974 and 2013. The average number of years since publication was 17.6 years, and 45 of the publications were from the 2000s. A significant, modest positive correlation was found between years since publication and the number of citations among the top 100 cited articles (r = 0.316; p = 0.001). A total of 55 journals published these 100 most cited articles. Nine documents were published in Clinical Toxicology, whereas eight documents were published in Annals of Emergency Medicine. Citations per year since publication for the top 100 most-cited articles ranged from 1.5 to 42.6 and had a mean of 8.5 citations per year and a median of 5.9 with an interquartile range of 3.75-10.35. In relation to the origin of the research publications, they were from 8 countries. The USA had the largest number of articles, 47, followed by the UK and Australia with 38 and nine articles respectively.

CONCLUSIONS

This study is the first bibliometric assessment of the top 100 cited articles in toxicology literature. Interest in paracetamol poisoning as a serious clinical problem continues to grow. Research published in high-impact journals and from high income countries is most likely to be cited in published paracetamol research.

Use and knowledge of single dose activated charcoal: A survey of Australian doctors

OBJECTIVE

The use of single dose activated charcoal (SDAC) as a means of gastric decontamination is declining. The present study examined the potential use of SDAC in common overdose scenarios by Australian emergency doctors, compared with clinical toxicologists and current guidelines.

METHODS

We conducted a cross-sectional survey of emergency doctors and toxicologists on the use of SDAC. The survey covered demographic data, education and previous use of SDAC and six clinical scenarios. The scenarios selected included agents not bound to SDAC, sustained-release preparations and ingestions at varying time points. Statistical calculations were performed using Fisher's exact test.

RESULTS

There were 397 emergency doctors and 20 toxicologists who responded to the survey. Seventy-one per cent (n = 280/397) of emergency doctors indicated they had received some education on decontamination. Eighty-three per cent (n = 331/397) had administered SDAC during their medical career, 29% (n = 117/397) within the past year. There was a significant difference in responses between emergency doctors and toxicologists in two scenarios; a toxic paracetamol ingestion presenting within 1 h (P = 0.009) and verapamil ingestion in a 3 year old boy (P = 0.001). Toxicologists were more likely to administer SDAC in these scenarios, 89% (n = 16/18) and 88% (n = 15/17), respectively, compared with 52% (n = 197/381) and 43% (n = 158/371) of emergency doctors.

CONCLUSIONS

Our study showed that there is a significant variation in the use of SDAC between toxicologists and emergency doctors in some scenarios. Clinical toxicologists are more likely to administer SDAC in certain overdose settings. It is essential to provide education on the benefits versus actual risks of SDAC in acute poisoning so that doctors will understand when to administer SDAC or seek further advice.

Current Controversies in Gastrointestinal Decontamination

Most poisonings reported to American poison control centers occur in the home. The most common route of exposure is ingestion, which is responsible for most fatalities. The goal of gastrointestinal decontamination is to prevent absorption of the toxin. Trends in treating poisoned patients have changed over the past few decades in light of a move toward practicing evidence-based medicine. Efficacy and clinical outcome have come into question and have led to position papers published recently regarding syrup of ipecac, gastric lavage, activated charcoal, and whole-bowel irrigation. These different methods of decontamination and the scientific data supporting each one will be reviewed, and the current controversies surrounding each will be discussed.

Current and future directions in the treatment and prevention of drug-induced liver injury: a systematic review

While the pace of discovery of new agents, mechanisms and risk factors involved in drug-induced liver injury (DILI) remains brisk, advances in the treatment of acute DILI seems slow by comparison. In general, the key to treating suspected DILI is to stop using the drug prior to developing irreversible liver failure. However, predicting when to stop is an inexact science, and commonly used ALT monitoring is an ineffective strategy outside of clinical trials. The only specific antidote for acute DILI remains N-acetylcysteine (NAC) for acetaminophen poisoning, although NAC is proving to be beneficial in some cases of non-acetaminophen DILI in adults. Corticosteroids can be effective for DILI associated with autoimmune or systemic hypersensitivity features. Ursodeoxycholic acid, silymarin and glycyrrhizin have been used to treat DILI for decades, but success remains anecdotal. Bile acid washout regimens using cholestyramine appear to be more evidenced based, in particular for leflunomide toxicity. For drug-induced acute liver failure, the use of liver support systems is still investigational in the United States and emergency liver transplant remains limited by its availability. Primary prevention appears to be the key to avoiding DILI and the need for acute treatment. Pharmacogenomics, including human leukocyte antigen genotyping and the discovery of specific DILI biomarkers offers significant promise for the future. This article describes and summarizes the numerous and diverse treatment and prevention modalities that are currently available to manage DILI.

Predicting the requirement for N-acetylcysteine in paracetamol poisoning from reported dose

Context

There is contention over whether reported dose correlates with toxicity in paracetamol poisoning and risk assessment is currently based on serum paracetamol concentration compared to a nomogram, irrespective of reported dose.

Objective

To determine if reported dose predicts the need for N-acetylcysteine (NAC).

Methods

Data were taken from paracetamol overdoses presenting to a tertiary toxicology service. Age, sex, reported dose, ingestion time, timed paracetamol concentrations between 4 and 16 h, hepatotoxicity (peak alanine transaminase > 1000 U/L) and treatment (single dose-activated charcoal [SDAC] and NAC) were analysed. Data were analysed within a repeated measures logistic regression framework using NONMEM (ver 7.2). The primary outcome was administration of NAC, which was determined based on a serum paracetamol concentration greater than the nomogram line.

Result

There were 1571 admissions in 1303 patients, with a median age of 27 years (12–96 years) and 1140 (73%) were females. The median dose was 10 g (1–100 g). The paracetamol concentration was above the nomogram line in 337 of 1571 (22%) patients. Patients presenting later (first paracetamol concentration between 7 and 16 h post-overdose) compared to those presenting earlier (4–7 h post-overdose) were more likely to have hepatotoxicity (5.5% vs. 0.4%; p < 0.0001), have a toxic paracetamol concentration (34% vs. 18%; p < 0.0001) and receive NAC (48% vs. 23%; p < 0.0001). SDAC reduced the probability of the paracetamol concentration being above the nomogram. Based on SDAC not being administered there was a 5% probability of requiring NAC at a dose of 6–9 g, a 10% chance of requiring NAC at a dose of 13–16 g, a 50% chance of requiring NAC at a dose of 30–34 g and a 90% chance for needing NAC at 48–50 g.

Conclusion

Reported dose was a good predictor of a toxic paracetamol concentration and SDAC reduced the probability of the concentration being above the nomogram. These predictions may assist in determining which patients could be started on NAC immediately.

Indications for single-dose activated charcoal administration in acute overdose

PURPOSE OF REVIEW

Gastrointestinal decontamination in overdose patients remains a controversial problem in emergency medicine. There has been a significant decrease in the use of single-dose activated charcoal (SDAC) in recent years based on little new evidence and possibly because the overall mortality in overdose patients is low.

RECENT FINDINGS

Human volunteer studies suggest SDAC is effective and this effect occurs for up to 4 h after ingestion, but the magnitude of the reduction in area under the curve (AUC) decreases over time. Two randomized controlled trials including one recent large study did not find SDAC to be beneficial. Pharmacokinetic and pharmacodynamic studies of specific drugs in overdose suggest that for most drugs SDAC decreases drug exposure, but this does not translate to clinical benefit in all cases. The administration of SDAC is a low-risk intervention.

SUMMARY

Although SDAC is unlikely to be beneficial in many overdose patients, for some subgroups with severe poisoning, the benefits will outweigh the low risk of administration. The use of SDAC should be based on the potential toxicity of the drug ingested and the potential benefit of SDAC balanced against the willingness of the patient to take SDAC and the low risk of administration.

Does prearrival communication from a poison center to an emergency department decrease time to activated charcoal for pediatric poisoning?

OBJECTIVE

A poison center plays an important role in directing appropriate care, which is critical in reducing morbidity due to poisoning. Activated charcoal (AC) is one intervention for some poisonings. This study examined whether children with a poisoning who were preannounced by a poison center received AC earlier than patients without a referral.

METHODS

A retrospective review of AC administration in children aged 0 to 18 years in a pediatric emergency department (ED) from 2000 to 2006 was performed. Abstracted covariates were poison center referral status, age, sex, acuity, disposition, transportation mode, triage time, and time of AC administration. Analysis of variance controlling for covariates tested the equality of mean time intervals between the groups with and without a poison center referral.

RESULTS

Three hundred fifty-one cases met the inclusion criteria. One hundred thirty-five (39%) were male. Eighty cases (23%) had a poison center referral. Time from triage to charcoal administration for patients with a poison center referral was a mean of 59 (SD, 34) minutes. Time for the group without a referral was a mean of 71 (SD, 43) minutes (P = 0.0036).

CONCLUSIONS

Advanced communication from a poison center was associated with earlier administration of AC in the ED for this population. Nevertheless, the duration to charcoal administration was frequently suboptimal. Triage and prehospital practices should be reexamined to improve timeliness of AC when indicated and consider exclusion of administration if beyond an appropriate time frame. Advanced notification should be the paradigm for all poison centers, and early response protocols for poison center referrals should be used by EDs.

Does cytochrome P450 liver isoenzyme induction increase the risk of liver toxicity after paracetamol overdose?

Paracetamol (acetaminophen, N-acetyl-p-aminophenol, 4-hydroxyacetanilide) is the most common cause of acute liver failure in developed countries. There are a number of factors which potentially impact on the risk of an individual developing hepatotoxicity following an acute paracetamol overdose. These include the dose of paracetamol ingested, time to presentation, decreased liver glutathione, and induction of cytochrome P450 (CYP) isoenzymes responsible for the metabolism of paracetamol to its toxic metabolite N-acetyl-p-benzoquinoneimine (NAPQI). In this paper, we review the currently published literature to determine whether induction of relevant CYP isoenzymes is a risk factor for hepatotoxicity in patients with acute paracetamol overdose. Animal and human in vitro studies have shown that the CYP isoenzyme responsible for the majority of human biotransformation of paracetamol to NAPQI is CYP2E1 at both therapeutic and toxic doses of paracetamol. Current UK treatment guidelines suggest that patients who use a number of drugs therapeutically should be treated as “high-risk” after paracetamol overdose. However, based on our review of the available literature, it appears that the only drugs for which there is evidence of the potential for an increased risk of hepatotoxicity associated with paracetamol overdose are phenobarbital, primidone, isoniazid, and perhaps St John’s wort. There is no evidence that other drugs often quoted as increasing risk, such as carbamazepine, phenytoin, primidone, rifampicin, rifabutin, efavirenz, or nevirapine, should be considered risk factors for hepatotoxicity in patients presenting with acute paracetamol overdose.

Gastrointestinal decontamination in the acutely poisoned patient

Objective

To define the role of gastrointestinal (GI) decontamination of the poisoned patient.

Data Sources

A computer-based PubMed/MEDLINE search of the literature on GI decontamination in the poisoned patient with cross referencing of sources.

Study Selection and Data Extraction

Clinical, animal and in vitro studies were reviewed for clinical relevance to GI decontamination of the poisoned patient.

Data Synthesis

The literature suggests that previously, widely used, aggressive approaches including the use of ipecac syrup, gastric lavage, and cathartics are now rarely recommended. Whole bowel irrigation is still often recommended for slow-release drugs, metals, and patients who "pack" or "stuff" foreign bodies filled with drugs of abuse, but with little quality data to support it. Activated charcoal (AC), single or multiple doses, was also a previous mainstay of GI decontamination, but the utility of AC is now recognized to be limited and more time dependent than previously practiced. These recommendations have resulted in several treatment guidelines that are mostly based on retrospective analysis, animal studies or small case series, and rarely based on randomized clinical trials.

Conclusions

The current literature supports limited use of GI decontamination of the poisoned patient.

Comparison of the effects of N-acetyl cysteine and erdosteine in rats with renal injury caused by paracetamol intoxication

Aim: The aim of the present study was to investigate the therapeutic and preventive effects of N-acetyl cysteine and erdosteine on renal injury associated with paracetamol (acetaminophen) intoxication. Materials and methods: Female albino Wistar rats were divided into six groups: control; paracetamol (1 g/kg, oral); paracetamol (1 g/kg, oral) + erdosteine (150 mg/kg/day, oral); paracetamol (1 g/kg, oral) + N-acetyl cysteine (140 mg/kg bolus, followed by 70 mg/kg, oral); N-acetyl cysteine control (140 mg/kg bolus, followed by 70 mg/kg, oral); and erdosteine control (150 mg/kg/day, oral). Potential renal injury was assessed using biochemical analyses, radionuclide imaging, and histopathological parameters. Results: In the paracetamol group, blood urea nitrogen and creatinine levels were significantly increased compared with controls. Histopathological examination showed tubular vacuolization, tubular necrosis, and remarkable interstitial inflammation. The excretion function was observed to be insufficient on radionuclide imaging. However, in the groups treated with erdosteine or N-acetyl cysteine after paracetamol, biochemical analyses, radionuclide imaging, and histopathological parameters showed significantly less evidence of renal toxicity than that observed in the group receiving paracetamol alone. Less renal toxicity was detected in rats receiving N-acetyl cysteine than in those receiving erdosteine. Conclusion: Renal injury may develop after paracetamol overdose. Erdosteine and N-acetyl cysteine are both effective in the prevention of renal injury when given in the early phase of paracetamol nephrotoxicity. N-acetyl cysteine is more protective than erdosteine.

Gentiana manshurica Kitagawa prevents acetaminophen-induced acute hepatic injury in mice via inhibiting JNK/ERK MAPK pathway

AIM: To investigate the in vivo hepatoprotective effects and mechanisms of Gentiana manshurica Kitagawa (GM) in acetaminophen (APAP)-induced liver injury in mice.

METHODS: GM (200, 150 or 50 mg/kg body weight) or N-acetyl-L-cysteine (NAC; 300 mg/kg body weight) was administrated orally with a single dose 2 h prior to APAP (300 mg/kg body weight) injection in mice.

RESULTS: APAP treatment significantly depleted hepatic glutathione (GSH), increased serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and malonyldialdehyde (MDA) and 4-hydroxynonenal levels, and decreased hepatic activity of glutathione peroxidase (GSH-px) and superoxide dismutase (SOD). However, the pretreatment of GM significantly alleviated APAP-induced oxidative stress by increasing GSH content, decreasing serum ALT, AST and MDA, and retaining the activity of GSH-px and SOD in the liver. Furthermore, GM pretreatment can inhibit caspase-3 activation and phosphorylation of c-Jun-NH2-terminal protein kinase 2 (JNK1/2) and extracellular signal-regulated kinase (ERK). GM also remarkably attenuated hepatocyte apoptosis confirmed by the terminal deoxynucleotidyl transferase mediated dUTP nick end-labeling method.

CONCLUSION: Hepatoprotective effects of GM against APAP-induced acute toxicity are mediated either by preventing the decline of hepatic antioxidant status or its direct anti-apoptosis capacity. These results support that GM is a potent hepatoprotective agent.

Drugs and pharmaceuticals: management of intoxication and antidotes

The treatment of patients poisoned with drugs and pharmaceuticals can be quite challenging. Diverse exposure circumstances, varied clinical presentations, unique patient-specific factors, and inconsistent diagnostic and therapeutic infrastructure support, coupled with relatively few definitive antidotes, may complicate evaluation and management. The historical approach to poisoned patients (patient arousal, toxin elimination, and toxin identification) has given way to rigorous attention to the fundamental aspects of basic life support--airway management, oxygenation and ventilation, circulatory competence, thermoregulation, and substrate availability. Selected patients may benefit from methods to alter toxin pharmacokinetics to minimize systemic, target organ, or tissue compartment exposure (either by decreasing absorption or increasing elimination). These may include syrup of ipecac, orogastric lavage, activated single- or multi-dose charcoal, whole bowel irrigation, endoscopy and surgery, urinary alkalinization, saline diuresis, or extracorporeal methods (hemodialysis, charcoal hemoperfusion, continuous venovenous hemofiltration, and exchange transfusion). Pharmaceutical adjuncts and antidotes may be useful in toxicant-induced hyperthermias. In the context of analgesic, anti-inflammatory, anticholinergic, anticonvulsant, antihyperglycemic, antimicrobial, antineoplastic, cardiovascular, opioid, or sedative-hypnotic agents overdose, N-acetylcysteine, physostigmine, L-carnitine, dextrose, octreotide, pyridoxine, dexrazoxane, leucovorin, glucarpidase, atropine, calcium, digoxin-specific antibody fragments, glucagon, high-dose insulin euglycemia therapy, lipid emulsion, magnesium, sodium bicarbonate, naloxone, and flumazenil are specifically reviewed. In summary, patients generally benefit from aggressive support of vital functions, careful history and physical examination, specific laboratory analyses, a thoughtful consideration of the risks and benefits of decontamination and enhanced elimination, and the use of specific antidotes where warranted. Data supporting antidotes effectiveness vary considerably. Clinicians are encouraged to utilize consultation with regional poison centers or those with toxicology training to assist with diagnosis, management, and administration of antidotes, particularly in unfamiliar cases.

Management of acute paracetamol poisoning in a tertiary care hospital

OBJECTIVES

To compare the management of acute paracetamol poisoning with the best evidence available, and to determine the effect of plasma paracetamol level estimation on the management.

DESIGN

Descriptive study with an intervention.

SETTING

Medical wards of the National Hospital of Sri Lanka, Colombo.

PATIENTS

Patients admitted with a history of acute paracetamol poisoning.

INTERVENTION

Measurement of plasma paracetamol.

METHODS

Data were obtained from the patients, medical staff and medical records. Plasma paracetamol was estimated between 4-24 hours of paracetamol ingestion. The current management practices were compared with the best evidence on acute paracetamol poisoning management.

RESULTS

157 patients were included. The mean ingested dose of paracetamol was 333 mg/kg body weight. Majority of the patients (84%) were transfers. Induced emesis and activated charcoal were given to 91% of patients. N-acetylcysteine was given to 66, methionine to 55, and both to 2. Aclinically important delay in the administration of antidotes was noted; 68% of patients received antidotes after 8 hours of the acute ingestion. Only 31 (26%) had paracetamol levels above the Rumack-Matthew normogram. 74 patients received an antidote despite having a plasma paracetamol level below the toxic level according to the normogram.

INTERPRETATION

Management of acute paracetamol poisoning could be improved by following best available evidence and adapting cheaper methods for plasma paracetamol estimation.

Evidence and consequences of spectrum bias in studies of criteria for liver transplant in paracetamol hepatotoxicity

OBJECTIVE

In severe paracetamol hepatotoxicity, orthotopic liver transplant (OLT) is a standard treatment in patients judged to have a hopeless prognosis. The most commonly used criteria to make this decision are the King's College Criteria (KCC). We aimed to compare the expected survival for patients who meet the KCC and do not receive transplant and those who receive OLT.

METHODS

A systematic review of studies of survival in patients who met the KCC according to whether they were transplanted. Data from these studies was extrapolated to compare long-term survival with and without adjustment for Quality of Life.

RESULTS

The survival of patients meeting KCC and undergoing transplant has not been specifically studied. UK data on transplants for acute liver failure indicate 1 and 10 year survival rates of 65 and 44%, respectively. Survival in those without transplant was documented in 15 studies. The average long-term survival rate was 24.9%. Survival was worse in studies originating in the King's unit (13.8 vs. 30.0%). It was apparent that this may be due to spectrum bias occurring in this much larger unit. There was clear evidence that those with the best prognosis were preferentially transplanted at the Kings liver unit, indicating the criteria may perform significantly worse at predicting death without transplant than previously estimated. Even so, for a 20-year-old meeting KCC, the best estimate of life expectancy with transplant (13.5 years) is no better than without (13.4 years). Adjustment for quality of life made OLT clearly a worse option.

CONCLUSION

Criteria for OLT that have a much higher positive predictive value (for death without transplant) are required. Such studies must be conducted only on those who would be considered suitable for transplant. Non-orthotopic liver transplant may be a preferred option in such circumstances, although much more data on survival after this procedure are required.

Effects of Erdosteine on Acetaminophen-induced Hepatotoxicity in Rats

We investigated the effects of erdosteine on acetaminophen (APAP)-induced hepatotoxicity in rats. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), AST (aspartate aminotransferase), and ALT (alanine transaminase) activities, and malonyldialdehyde (MDA) and nitric oxide levels as oxidant/antioxidant biochemical parameters were investigated with light microscopic evaluation in adult female Wistar Albino rats. APAP administration produced a decrease in hepatic SOD, CAT, and GSH-Px activities, and coadministration of erdosteine (150 and 300 mg/kg) resulted in increases in the activities. MDA and NO levels increased in the APAP group, and erdosteine treatments prevented these increases. Significant elevations in serum AST and ALT levels were observed in the APAP group, and when erdosteine and APAP were coadministered, their serum levels were close to those in the control group. Light microscopic evaluation of livers showed that there were remarkable centrilobular (zone III) hepatic necrosis and mild to moderate sinusoidal congestion in the APAP group, whereas in the erdosteine group, cellular necrosis was minimal and the hepatocytes maintained a better morphology when compared to the APAP group. Erdosteine prevented APAP-induced liver injury and toxic side effects probably through the antioxidant and radical scavenging effects of erdosteine.

Toxicology in the critical care unit

Toxicologic conditions are encountered in critically ill patients due to intentional or unintentional misuse of or exposure to therapeutic or illicit drugs. Additionally, toxicities related to medical interventions may develop in hospitalized patients. This review focuses on recent developments in the field of critical care toxicology. Early interventions to decrease absorption or enhance elimination of toxins have limited value. Specific interventions to manage toxicities due to analgesics, sedative-hypnotics, antidepressants, antipsychotics, cardiovascular agents, alcohols, carbon monoxide, and cholinergic agents are reviewed. Hospital-acquired toxicities due to methemoglobinemia, propylene glycol, and propofol should be recognized and treated. The clinician is continually required to incorporate clinical judgment along with available scientific data and clinical evidence to determine the best therapy for toxicologic conditions.

Guidelines for the management of paracetamol poisoning in Australia and New Zealand--explanation and elaboration. A consensus statement from clinical toxicologists consulting to the Australasian poisons information centres

Paracetamol is involved in a large proportion of accidental paediatric exposures and deliberate self-poisoning cases, although subsequent hepatic failure and death are both uncommon outcomes. The optimal management of most patients with paracetamol overdose is usually straightforward. However, several differing nomograms and varying recommendations regarding potential risk factors for hepatic injury introduce complexity. In order to reconcile management advice with current Australasian clinical toxicology practice, revised guidelines have been developed by a panel of clinical toxicologists consulting to the poisons information centres in Australia and New Zealand using a workshop and consultative process. This article summarises the rationale for the recommendations made in these new guidelines.

An audit of the NICE self-harm guidelines at a local Accident and Emergency department in North Wales

This paper reports the findings of a self-harm audit based on data collected at an A&E department in North Wales. The National Institute for Clinical Excellence (NICE) guidelines on the short term physical and psychological management of self-harm were published in 2004 and the audit was based on technical criteria recommended in the guideline booklet, including standards of psychosocial assessment, staff training and patient satisfaction information. The data in this study related to fifty consecutive self-harm attendances at the A&E department Ysbyty Glan Clwyd in the Spring of 2007. The hospital serves a mixed rural/urban population of approximately 250,000. Patient satisfaction questionnaires were made available to the group subsequently, whilst the staff training audit was distributed more widely to include emergency, medicine and mental health divisions of the Conwy & Denbighshire NHS Trust. The results demonstrated generally high standards of care on psychosocial assessment, though information relating to initial ambulance involvement in treatment was often unclear. The response to the staff-training questionnaire was an encouraging 44% and indicated wide variations between staff groups and areas of work. The patient satisfaction returns demonstrated favourable responses, with several comments added to expand on tick box replies. Service developments, as a result of the audit, include the proposal to provide mental health and self-harm training to all those staff likely to encounter the behaviour--not just to those who work in mental health. Patients, from the questionnaire, who express a willingness to become part of a mental health planning group are now provided details of the patient participation involvement (PPI) group, where their experiences can often inform service improvement. Meanwhile the case note audit has reinforced the need for a practical self-harm pathway which will ensure consistency.

The effect of yogurt on acetaminophen absorption by activated charcoal and burnt toast

Although acetaminophen overdose can be treated with N-acetylcysteine, activated charcoal is useful in preventing absorption of acetaminophen from the gut. Mixing activated charcoal with yogurt may make the dose more palatable. We investigated effects of yogurt on absorption of acetaminophen by burnt toast or activated charcoal in intestinal fluid using an in vitro model. The aliquots of phosphate buffer saline (PBS) were supplemented with high concentrations of acetaminophen after adjusting the pH to 7.2 (to mimic intestinal fluid). Then specimens were treated with various dosages (15 mg/mL, 25 mg/mL, or 50 mg/mL) of activated charcoal or burnt toast. A small amount of fluid was withdrawn at 0, 5, 10, 20, and 30 min and acetaminophen concentrations were measured by the fluorescence polarization immunoassay (FPIA). We also treated other aliquots of PBS buffer containing acetaminophen with activated charcoal and yogurt or burnt toast and yogurt. Then small aliquots were withdrawn at specific time intervals to determine concentrations of acetaminophen. Activated charcoal was very effective in removing acetaminophen from intestinal fluids and the presence of yogurt insignificantly affected such absorptions. In contrast, burnt toast had a modest effect on removing acetaminophen from fluids but yogurt significantly increased the capability of burnt toast to absorb acetaminophen. However, the activated charcoal/yogurt combination is more effective than the burnt toast/yogurt combination for absorbing acetaminophen.

Pharmacokinetic-pharmacodynamic modelling of QT interval prolongation following citalopram overdoses

AIMS

To develop a pharmacokinetic-pharmacodynamic model describing the time-course of QT interval prolongation after citalopram overdose and to evaluate the effect of charcoal on the relative risk of developing abnormal QT and heart-rate combinations.

METHODS

Plasma concentrations and electrocardiograph (ECG) data from 52 patients after 62 citalopram overdose events were analysed in WinBUGS using a Bayesian approach. The reported doses ranged from 20 to 1700 mg and on 17 of the events a single dose of activated charcoal was administered. The developed pharmacokinetic-pharmacodynamic model was used for predicting the probability of having abnormal combinations of QT-RR, which was assumed to be related to an increased risk for torsade de pointes (TdP).

RESULTS

The absolute QT interval was related to the observed heart rate with an estimated individual heart-rate correction factor [alpha = 0.36, between-subject coefficient of variation (CV) = 29%]. The heart-rate corrected QT interval was linearly dependent on the predicted citalopram concentration (slope = 40 ms l mg(-1), between-subject CV = 70%) in a hypothetical effect-compartment (half-life of effect-delay = 1.4 h). The heart-rate corrected QT was predicted to be higher in women than in men and to increase with age. Administration of activated charcoal resulted in a pronounced reduction of the QT prolongation and was shown to reduce the risk of having abnormal combinations of QT-RR by approximately 60% for citalopram doses above 600 mg.

CONCLUSION

Citalopram caused a delayed lengthening of the QT interval. Administration of activated charcoal was shown to reduce the risk that the QT interval exceeds a previously defined threshold and therefore is expected to reduce the risk of TdP.

Efficacy of activated charcoal administered more than four hours after acetaminophen overdose

To evaluate whether administration of activated charcoal, in addition to standard N-acetylcysteine (NAC) therapy, after acetaminophen overdose provides additional patient benefit over NAC therapy alone, a 1-year non-randomized prospective, multi-center, observational case series was performed at three poison centers and one poison center system. Entrance criteria were all acute acetaminophen overdoses with: 1) an acetaminophen blood concentration determined to be in the toxic range by the Rumack-Matthew nomogram; and 2) all therapies, including NAC and activated charcoal, initiated between 4 and 16 h post-ingestion. There were 145 patients meeting entrance criteria, of whom 58 patients (40%) received NAC only and 87 patients (60%) received NAC and activated charcoal. Overall, 23 patients had elevations of AST or ALT greater than 1000 IU/L, of which 21 patients received NAC only (38% of total NAC only group) and 2 patients received NAC and activated charcoal (2% of total NAC+AC group). Administration of activated charcoal in this series of patients with toxic acetaminophen concentrations treated with NAC was associated with reduced incidence of liver injury, as measured by elevated serum transaminases and prothrombin times.

Interventions for paracetamol (acetaminophen) overdose

BACKGROUND

Poisoning with paracetamol (acetaminophen) is a common cause of hepatotoxicity in the Western World. Inhibition of absorption, removal from the vascular system, antidotes, and liver transplantation are interventions for paracetamol poisoning.

OBJECTIVES

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

SEARCH STRATEGY

We identified trials through electronic databases, manual searches of bibliographies and journals, authors of trials, and pharmaceutical companies until December 2005.

SELECTION CRITERIA

Randomised clinical trials and observational studies were included.

DATA COLLECTION AND ANALYSIS

The primary outcome measure was all-cause mortality plus liver transplantation. Secondary outcome measures were clinical symptoms, (eg, hepatic encephalopathy, fulminant hepatic failure), hepatotoxicity, adverse events, and plasma paracetamol concentration. We used Peto odds ratios and odds ratios with 95% confidence intervals (CI) for analysis of outcomes. Random- and fixed-effects meta-analyses were performed.

MAIN RESULTS

Ten small and low-methodological quality randomised trials, one quasi-randomised study, and 48 observational studies were identified. It was not possible to perform relevant meta-analyses of randomised trials that have addressed our outcome measures. Activated charcoal, gastric lavage, and ipecacuanha are able to reduce the absorption of paracetamol, but the clinical benefit is unclear. Of these, activated charcoal seems to have the best risk-benefit ratio. N-acetylcysteine seems preferable to placebo/supportive treatment, dimercaprol, and cysteamine, but N-acetylcysteine's superiority to methionine is unproven. It is not clear which N-acetylcysteine treatment protocol offers the best efficacy. No strong evidence supports other interventions for paracetamol overdose. N-acetylcysteine may reduce mortality in patients with fulminant hepatic failure (Peto OR 0.26, 95% CI 0.09 to 0.94, one trial). Liver transplantation has the potential to be life saving in fulminant hepatic failure, but refinement of selection criteria for transplantation and long-term outcome reporting are required.

AUTHORS' CONCLUSIONS

Our results highlight a paucity of randomised trials on interventions for paracetamol overdose. Activated charcoal seems the best choice to reduce absorption. N-acetylcysteine should be given to patients with overdose but the selection criteria are not clear. No N-acetylcysteine regime has been shown to be more effective than any other. It is a delicate balance when to proceed to liver transplantation, which may be life-saving for patients with poor prognosis.

Acetaminophen poisoning: an evidence-based consensus guideline for out-of-hospital management

The objective of this guideline is to assist poison center personnel in the appropriate out-of-hospital triage and initial management of patients with suspected ingestions of acetaminophen. An evidence-based expert consensus process was used to create this guideline. This guideline applies to ingestion of acetaminophen alone and is based on an assessment of current scientific and clinical information. The expert consensus panel recognizes that specific patient care decisions may be at variance with this guideline and are the prerogative of the patient and the health professionals providing care. The panel's recommendations follow. These recommendations are provided in chronological order of likely clinical use. The grade of recommendation is provided in parentheses. 1) The initial history obtained by the specialist in poison information should include the patient's age and intent (Grade B), the specific formulation and dose of acetaminophen, the ingestion pattern (single or multiple), duration of ingestion (Grade B), and concomitant medications that might have been ingested (Grade D). 2) Any patient with stated or suspected self-harm or who is the recipient of a potentially malicious administration of acetaminophen should be referred to an emergency department immediately regardless of the amount ingested. This referral should be guided by local poison center procedures (Grade D). 3) Activated charcoal can be considered if local poison center policies support its prehospital use, a toxic dose of acetaminophen has been taken, and fewer than 2 hours have elapsed since the ingestion (Grade A). Gastrointestinal decontamination could be particularly important if acetylcysteine cannot be administered within 8 hours of ingestion. Acute, single, unintentional ingestion of acetaminophen: 1) Any patient with signs consistent with acetaminophen poisoning (e.g., repeated vomiting, abdominal tenderness in the right upper quadrant or mental status changes) should be referred to an emergency department for evaluation (Grade D). 2) Patients less than 6 years of age should be referred to an emergency department if the estimated acute ingestion amount is unknown or is 200 mg/kg or more. Patients can be observed at home if the dose ingested is less than 200 mg/kg (Grade B). 3) Patients 6 years of age or older should be referred to an emergency department if they have ingested at least 10 g or 200 mg/kg (whichever is lower) or when the amount ingested is unknown (Grade D). 4) Patients referred to an emergency department should arrive in time to have a stat serum acetaminophen concentration determined at 4 hours after ingestion or as soon as possible thereafter. If the time of ingestion is unknown, the patient should be referred to an emergency department immediately (Grade D). 5) If the initial contact with the poison center occurs more than 36 hours after the ingestion and the patient is well, the patient does not require further evaluation for acetaminophen toxicity (Grade D). Repeated supratherapeutic ingestion of acetaminophen (RSTI): 1) Patients under 6 years of age should be referred to an emergency department immediately if they have ingested: a) 200 mg/kg or more over a single 24-hour period, or b) 150 mg/kg or more per 24-hour period for the preceding 48 hours, or c) 100 mg/kg or more per 24-hour period for the preceding 72 hours or longer (Grade C). 2) Patients 6 years of age or older should be referred to an emergency department if they have ingested: a) at least 10 g or 200 mg/kg (whichever is less) over a single 24-hour period, or b) at least 6 g or 150 mg/kg (whichever is less) per 24-hour period for the preceding 48 hours or longer. In patients with conditions purported to increase susceptibility to acetaminophen toxicity (alcoholism, isoniazid use, prolonged fasting), the dose of acetaminophen considered as RSTI should be greater than 4 g or 100 mg/kg (whichever is less) per day (Grade D). 3) Gastrointestinal decontamination is not needed (Grade D). Other recommendations: 1) The out-of-hospital management of extended-release acetaminophen or multi-drug combination products containing acetaminophen is the same as an ingestion of acetaminophen alone (Grade D). However, the effects of other drugs might require referral to an emergency department in accordance with the poison center's normal triage criteria. 2) The use of cimetidine as an antidote is not recommended (Grade A).

The Changing Indications of Gastrointestinal Decontamination in Poisonings

Gastrointestinal (GI) decontamination is commonly used in the treatment of the poisoned patient. Although the practice is widely accepted, the science behind the recommendations is limited. This article describes commonly used techniques for GI decontamination and critically reviews the studies evaluating these treatments.

Gastrointestinal decontamination

Overall, no conclusive data support the use of gastric decontamination in the routine management of the poisoned patient. Studies of asymptomatic patients suggest that no treatment is required, and, given the complications that have been reported, this may be a reasonable approach to' most patients. Even in symptomatic patients, the only demonstrable benefit was found in a post-hoc subgroup analysis and involved an outcome of questionable clinical importance. Given these data, it would be easy to conclude that GI decontamination has no role in the management of the poisoned patient. This conclusion is valid when considering poisoned patients as a group, but all poisoned patients are not the same. Patients with trivial ingestion do well without treatment, and their greatest risk is an iatrogenic complication. Even patients with more serious ingestions usually have good outcomes with supportive care alone. It is no longer sufficient to justify GL or forced administration of AC with the supposition that "the patient could have taken something bad." However,there are some overdoses where limiting the systemic absorption of the poison may limit the toxic effects and prevent serious toxicity. After careful consideration of the risks, GI decontamination should be targeted at patients who, in the opinion of the treating physician, have a potentially life-threatening exposure.

Paracetamol overdose and hepatotoxicity at a regional Australian hospital: a 4-year experience

BACKGROUND

Paracetamol is a component of a number of drugs taken in overdose (OD). The influence of alcohol use (acute or chronic) on the presentation and clinical course of paracetamol OD is contentious. This study explores the relationship between paracetamol OD, alcohol consumption and clinical outcomes at a regional Australian hospital.

AIMS

To determine the frequency, circumstances and outcomes of paracetamol OD presentations to a regional Australian general hospital over a 4-year period.

METHODS

Medical records of patients admitted to the Ballarat Health Services (BHS) as a result of paracetamol OD between January 2000 and December 2003 were reviewed. Patient demographics, amount of paracetamol ingested, other drug coingestions, alcohol history, previous medication OD, clinical course and outcomes were recorded.

RESULTS

Annual admissions resulting from paracetamol OD almost doubled during the 4 years studied. The risk of a repeat paracetamol OD was highest within 4 weeks of the initial OD. Alcohol, benzodiazepines and antidepressants were commonly coingested. The strongest predictor of severe hepatotoxicity was delayed or no N-acetyl cysteine treatment in patients consuming greater than 10 g of paracetamol or with toxic serum paracetamol levels. A history of alcohol consumption did not appear to worsen outcomes.

Prehospital activated charcoal: the way forward

OBJECTIVES

Single dose activated charcoal (SDAC) may be an effective method of gastric decontamination when administered to patients within an hour of drug overdose. However, few patients who may benefit from this treatment attend an emergency department within this timeframe. The authors sought to determine the current attitudes of ambulance NHS trusts to recent recommendations that the administration of SDAC should be considered as a prehospital therapy.

METHODS

A postal questionnaire was used to determine the current level of use of prehospital activated charcoal by ambulance NHS trusts, the incidence of associated complications, and barriers preventing the routine use of prehospital SDAC.

RESULTS

A completed questionnaire was returned by 36 of the 39 ambulance NHS trusts in the UK (response rate 92%). Currently none of the trusts that responded to the questionnaire provides prehospital SDAC as an intervention. The most common barriers to the provision of prehospital SDAC are the current lack of evidence in the medical literature proving it is effective in improving patient outcome and the lack of a recognised protocol for its administration. Other issues included concerns regarding potential complications, ambulance turnaround times, lack of availability of SDAC, and lack of funding.

CONCLUSIONS

A lack of published evidence proving efficacy remains the most important factor in preventing the routine administration of SDAC to appropriate patients in the prehospital environment. Further research in this setting is required to determine the usefulness of this therapy.