Reduction of adverse effects from intravenous acetylcysteine treatment for paracetamol poisoning: a randomised controlled trial

Plasma paracetamol concentration at hospital presentation has a dose-dependent relationship with liver injury despite prompt treatment with intravenous acetylcysteine

CONTEXT

Paracetamol (acetaminophen) overdose is a common reason for emergency hospital admission in the UK and the leading cause of acute liver failure in the Western world. Currently, the antidote acetylcysteine (NAC) is administered at a dose determined only by body weight without regard for the body burden of paracetamol.

OBJECTIVE

To determine whether higher plasma paracetamol concentrations are associated with increased risk of liver injury despite prompt treatment with intravenous NAC.

METHODS

Patients admitted to hospital for treatment with intravenous NAC following a single acute paracetamol overdose entered the study if NAC was commenced within 24 h of drug ingestion (N = 727 hospital presentations). Based on the plasma paracetamol concentration at first presentation to hospital, a series of nomograms were created: 0-100, 101-150, 151-200, 201-300, 301-500 and over 501 mg/L. The primary endpoints were acute liver injury (ALI - peak serum ALT activity >150 U/L and double the admission value) and hepatotoxicity (peak ALT >1000 U/L).

RESULTS

ALI and hepatotoxicity were more common in patients with higher admission plasma paracetamol concentrations despite NAC treatment (ALI: nomogram 0-100: 6%, 101-150: 3%, 151-200: 3%, 201-300: 9%, 301-500: 13%, over 501 mg/dL: 27%. p < 0.0001). This dose-response relationship between paracetamol concentration and ALI persisted even in patients treated with NAC within 8 h of overdose (nomogram 0-100: 0%, 101-150: 0.8%, 151-200: 2%, 201-300: 3.6%, 301-500: 12.5%, over 501mg/L: 33%. p < 0.0001) and in patients with normal ALT activity at first presentation (nomogram: 0-100: 0%, 101-150: 1.2%, 151-200: 1.5%, 201-300: 5.3%, 301-500: 10.8% p < 0.0001).

DISCUSSION

Patients with increased concentrations of plasma paracetamol at hospital presentation are at higher risk of liver injury even when intravenous NAC is promptly administered before there is biochemical evidence of toxicity.

CONCLUSION

This study supports theoretical concerns that the current intravenous dose of NAC may be too low in the setting of higher paracetamol exposure.

Antioxidant and hepatoprotective activity of vitex honey against paracetamol induced liver damage in mice

Fourteen vitex honeys from China were investigated to evaluate its antioxidant and hepatoprotective activity against paracetamol-induced liver damage. All honey samples exhibited high total phenolic content (344-520 mg GAE per kg), total flavonoid content (19-31 mg Rutin per kg), and strong antioxidant activity in DPPH radical scavenging, ferric reducing antioxidant power and Ferrous ion-chelating ability. Nine phenolic acids were detected in vitex honey samples, in which caffeic acid was the main compound. Honey from Heibei Zanhuang (S2) ranked the highest antioxidant activity was orally administered to mice (5 g kg(-1), 20 g kg(-1)) for 70 days. In high-dose (20 g kg(-1)), vitex honey pretreatment resulting in significant increase in serum oxygen radical absorbance capacity (15.07%) and decrease in Cu(2+)-mediate lipoprotein oxidation (80.07%), and suppression in alanine aminotransferase (75.79%) and aspartate aminotransferase (74.52%), enhancement in the superoxide dismutase and glutathione peroxidase activities and reduction in malondialdehyde (36.15%) and 8-hydroxy-2'-deoxyguanosine (19.6%) formation compared with paracetamol-intoxicated group. The results demonstrated the hepatoprotection of vitex honey against paracetamol-induced liver damage might attribute to its antioxidant and/or perhaps pro-oxidative property.

False positive acetaminophen concentrations in icteric serum

Introduction

Serum concentrations of acetaminophen are measured to predict the risk of hepatotoxicity in cases of acetaminophen overdose and to identify acetaminophen use in patients with acute liver injury without a known cause. The acetaminophen concentration determines if treatment with N-acetyl cysteine, the antidote for acetaminophen poisoning, is warranted.

Description

A 49-year-old woman was admitted to our hospital with a hepatic encephalopathy and a total serum bilirubin concentration of 442 µmol/l. The acetaminophen concentration of 11.5 mg/l was measured with an enzymatic-colorimetric assay, thus treatment with N-acetyl cysteine was started. Interestingly, the acetaminophen concentration remained unchanged (11.5–12.3 mg/l) during a period of 4 consecutive days. In contrast, the acetaminophen concentration measured by HPLC, a chromatographic technique, remained undetectable

Discussion

In the presented case, elevated bilirubin was the most likely candidate to interfere with acetaminophen assay causing false positive results. Bilirubin has intense absorbance in the ultraviolet and visible regions of the electromagnetic spectrum and for that reason it causes interference in an enzymatic-colorimetric assay.

Conclusion

False positive acetaminophen laboratory test results may be found in icteric serum, when enzymatic-colorimetric assays are used for determination of an acetaminophen concentration. Questionable acetaminophen results in icteric serum should be confirmed by a non-enzymatic method, by means of ultrafiltration of the serum, or by dilution studies.

Evidence for the changing regimens of acetylcysteine

Paracetamol overdose prior to the introduction of acetylcysteine was associated with significant morbidity. Acetylcysteine is now the mainstay of treatment for paracetamol poisoning and has effectively reduced rates of hepatotoxicity and death. The current three-bag intravenous regimen with an initial high loading dose was empirically derived four decades ago and has not changed since. This regimen is associated with a high rate of adverse effects due mainly to the high initial peak acetylcysteine concentration. Furthermore, there are concerns that the acetylcysteine concentration is not adequate for 'massive' overdoses and that the dose and duration may need to be altered. Various novel regimens have been proposed, looking to address these issues. Many of these modified regimens aim to decrease the rate of adverse reactions by slowing the loading dose and thereby decrease the peak concentration. We used a published population pharmacokinetic model of acetylcysteine to simulate these modified regimens. We determined mean peak and 20 h acetylcysteine concentrations and area under the under the plasma concentration-time curve to compare these regimens. Those regimens that resulted in a lower peak acetylcysteine concentration have been shown in studies to have a lower rate of adverse events. However, these studies were too small to show whether they are as effective as the traditional regimen. Further research is still needed to determine the optimum dose and duration of acetylcysteine that results in the fewest side-effects and treatment failures. Indeed, a more patient-tailored approach might be required, whereby the dose and duration are altered depending on the paracetamol dose ingested or paracetamol concentrations.

Outcomes of Patients With Premature Discontinuation of the 21-h Intravenous N-Acetylcysteine Protocol After Acute Acetaminophen Overdose

BACKGROUND

The minimum recommended treatment duration for i.v. N-acetylcysteine (NAC) after an acute, single acetaminophen (APAP) overdose is 21 h. Some have questioned whether shorter courses may be sufficient in carefully selected cases.

OBJECTIVE

We sought to describe the incidence of hepatotoxicity in a cohort of acute APAP overdose patients who received <21 h of i.v. NAC for any reason.

METHODS

We performed a secondary analysis of a large multicenter retrospective cohort of patients hospitalized for APAP poisoning. We selected patients with a potentially toxic serum APAP concentration measured between 4 and 24 h post ingestion, in whom i.v. NAC was initiated but discontinued before completing the full 21-h course. We further characterized outcomes in these patients as a function of two novel risk-prediction tools, the psi (ψ) parameter and APAP × aminotransferase (AT) product. The ψ parameter is an estimate of the cellular burden of injury based on the area under the concentration-time curve before treatment, and calculated with respect to the APAP concentration and time to initiation of NAC.

RESULTS

Fifty-nine patients met inclusion criteria. Intravenous NAC was initiated a median of 11.3 h post ingestion and administered for a median of 11.0 h. Hepatotoxicity (aspartate aminotransferase [AST] or alanine aminotransferase [ALT] > 1,000 IU/L) occurred in one patient (1.7%; 95% confidence interval 0.04-9.1), and eight additional patients developed hepatic injury (AST or ALT > 100 IU/L). No fatalities occurred. A multiplication product of APAP and AT (APAP × AT) that falls below 10,000 μmol/L/IU-L, or pretreatment ψ < 5 mmol/L-h suggested a low risk of hepatic injury.

CONCLUSIONS

In this retrospective analysis of patients treated with < 21 h of i.v. NAC for acute APAP overdose, the incidence of hepatotoxicity and coagulopathy was low, despite delays to NAC treatment.

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.

New regimens for intravenous acetylcysteine, where are we now?

Acetylcysteine has been used as a treatment for paracetamol overdose as a 20.25- or 21-h infusion for nearly 40 years. These regimens give 50% of the dose in the first 15 min or 1 h, and are associated with high rates of adverse reactions. A randomised controlled trial has demonstrated that a shorter (12 h) and simpler (two infusions) acetylcysteine regimen using a slower initial infusion rate produces lower rates of adverse events than the original 20.25-h regimen. However, this study was not sufficiently large to show therapeutic equivalence as a hepatoprotective therapy in paracetamol overdose. Two further studies are now reported, which also suggest lower rates of adverse reactions with lower initial rates of acetylcysteine administration. These modified regimens can now be accepted as better tolerated, but it is unlikely that a randomised study of sufficient size to demonstrate non-inferiority of any novel regimen would ever be funded. Against this background we suggest what can be done to establish the efficacy of these less toxic and potentially shorter alternative acetylcysteine regimens and to establish them into routine clinical use.

Risk of Acute Liver Failure in Patients With Drug-Induced Liver Injury: Evaluation of Hy's Law and a New Prognostic Model

BACKGROUND & AIMS

Few studies have evaluated the ability of laboratory tests to predict risk of acute liver failure (ALF) among patients with drug-induced liver injury (DILI). We aimed to develop a highly sensitive model to identify DILI patients at increased risk of ALF. We compared its performance with that of Hy's Law, which predicts severity of DILI based on levels of alanine aminotransferase or aspartate aminotransferase and total bilirubin, and validated the model in a separate sample.

METHODS

We conducted a retrospective cohort study of 15,353 Kaiser Permanente Northern California members diagnosed with DILI from 2004 through 2010, liver aminotransferase levels above the upper limit of normal, and no pre-existing liver disease. Thirty ALF events were confirmed by medical record review. Logistic regression was used to develop prognostic models for ALF based on laboratory results measured at DILI diagnosis. External validation was performed in a sample of 76 patients with DILI at the University of Pennsylvania.

RESULTS

Hy's Law identified patients that developed ALF with a high level of specificity (0.92) and negative predictive value (0.99), but low level of sensitivity (0.68) and positive predictive value (0.02). The model we developed, comprising data on platelet count and total bilirubin level, identified patients with ALF with a C statistic of 0.87 (95% confidence interval [CI], 0.76-0.96) and enabled calculation of a risk score (Drug-Induced Liver Toxicity ALF Score). We found a cut-off score that identified patients at high risk patients for ALF with a sensitivity value of 0.91 (95% CI, 0.71-0.99) and a specificity value of 0.76 (95% CI, 0.75-0.77). This cut-off score identified patients at high risk for ALF with a high level of sensitivity (0.89; 95% CI, 0.52-1.00) in the validation analysis.

CONCLUSIONS

Hy's Law identifies patients with DILI at high risk for ALF with low sensitivity but high specificity. We developed a model (the Drug-Induced Liver Toxicity ALF Score) based on platelet count and total bilirubin level that identifies patients at increased risk for ALF with high sensitivity.

Comprehensive microRNA profiling in acetaminophen toxicity identifies novel circulating biomarkers for human liver and kidney injury

Our objective was to identify microRNA (miRNA) biomarkers of drug-induced liver and kidney injury by profiling the circulating miRNome in patients with acetaminophen overdose. Plasma miRNAs were quantified in age- and sex-matched overdose patients with (N = 27) and without (N = 27) organ injury (APAP-TOX and APAP-no TOX, respectively). Classifier miRNAs were tested in a separate cohort (N = 81). miRNA specificity was determined in non-acetaminophen liver injury and murine models. Sensitivity was tested by stratification of patients at hospital presentation (N = 67). From 1809 miRNAs, 75 were 3-fold or more increased and 46 were 3-fold or more decreased with APAP-TOX. A 16 miRNA classifier model accurately diagnosed APAP-TOX in the test cohort. In humans, the miRNAs with the largest increase (miR-122-5p, miR-885-5p, miR-151a-3p) and the highest rank in the classifier model (miR-382-5p) accurately reported non-acetaminophen liver injury and were unaffected by kidney injury. miR-122-5p was more sensitive than ALT for reporting liver injury at hospital presentation, especially combined with miR-483-3p. A miRNA panel was associated with human kidney dysfunction. In mice, miR-122-5p, miR-151a-3p and miR-382-5p specifically reported APAP toxicity - being unaffected by drug-induced kidney injury. Profiling of acetaminophen toxicity identified multiple miRNAs that report acute liver injury and potential biomarkers of drug-induced kidney injury.

Combination Therapies for Traumatic Brain Injury: Retrospective Considerations

Patients enrolled in clinical trials for traumatic brain injury (TBI) may present with heterogeneous features over a range of injury severity, such as diffuse axonal injury, ischemia, edema, hemorrhage, oxidative damage, mitochondrial and metabolic dysfunction, excitotoxicity, inflammation, and other pathophysiological processes. To determine whether combination therapies might be more effective than monotherapy at attenuating moderate TBI or promoting recovery, the National Institutes of Health funded six preclinical studies in adult and immature male rats to evaluate promising acute treatments alone and in combination. Each of the studies had a solid rationale for its approach based on previous research, but only one reported significant improvements in long-term outcomes across a battery of behavioral tests. Four studies had equivocal results because of a lack of sensitivity of the outcome assessments. One study demonstrated worse results with the combination in comparison with monotherapies. While specific research findings are reported elsewhere, this article provides an overview of the study designs, insights, and recommendations for future research aimed at therapy development for TBI.

Changing the Management of Paracetamol Poisoning

PURPOSE

The management of paracetamol poisoning was revolutionized after use of acetylcysteine in the 1970s. The protocol used, 3 weight-related infusions, requires almost 24 hours in hospital. It is associated with adverse events in treated patients, particularly anaphylactoid reactions and vomiting. Present treatment nomograms were based on a small series of untreated patients: only 5 of 22 (23%) and 6 of 25 (24%) between the 100 to 200 mg/L and 200 to 300 mg/L nomogram lines, respectively, developed liver injury (alanine transaminase >1000 IU/L). Many patients treated today are unlikely to be at actual risk for major hepatotoxicity. This article discusses the background to future prospects in this area.

METHODS

The history behind approaches to the use of acetylcysteine is presented briefly. The rationale for, and key findings of, a new 12-hour antidote regimen for paracetamol poisoning are detailed. Newer markers of hepatotoxicity, such as miR-122, HMGB1, and necrosis K18, which predict patients at risk more reliably and earlier than existing tests, are discussed.

FINDINGS

A 2-phase 12-hour acetylcysteine infusion protocol (100 mg/kg over 2 hours: 200 mg/kg over 10 hours) was studied in a formal factorial design against the traditional 3-phase 20.25-hour infusion protocol, with and without pretreatment with ondansetron or placebo. The 12-hour regimen was associated with very significant reductions in anaphylactoid reactions (odds ratio = 0.23; 95% CI, 0.12-0.43; P < 0.0001) and vomiting (odds ratio = 0.37; 95% CI, 0.18-0.79; P = .003) compared with the 20.25-hour infusion protocol. There were few withdrawals from the clinical trial, indicating the feasibility of conducting such studies in Europe.

IMPLICATIONS

Novel proteomic markers are better than existing standard tests (alanine transaminase and international normalized ratio) early in the course of paracetamol poisoning. Together with these new biomarkers of hepatotoxicity, a 12-hour acetylcysteine protocol offers clinicians and patients the possibility for better targeting of therapy, fewer adverse effects, a simpler dosing regimen, and shorter hospital stay.

Paracetamol poisoning: beyond the nomogram

Paracetamol poisoning is the commonest overdose seen in the UK. The management of patients with paracetamol poisoning has been little changed for the past 40 years, with a weight related dose of antidote (acetylcysteine) and treatment based on nomograms relating paracetamol concentration to time from ingestion. In 2012 the UK Commission on Human Medicines recommended a revision of the nomogram, following the death of a young woman, lowering the treatment threshold for all patients. As a result many more patients were treated. This has resulted in a large increase in admissions and in the proportion suffering adverse reactions to the antidote acetylcysteine since, interestingly, higher paracetamol concentrations inhibit anaphylactoid reactions to the antidote. New approaches to assessing the toxicity of paracetamol are now emerging using new biomarkers in blood. This article discusses new approaches to risk assessment and treatment for paracetamol overdose based on recent research in this area.

Effect of amlodipine, lisinopril and allopurinol on acetaminophen-induced hepatotoxicity in rats

Background

Exposure to chemotherapeutic agents such as acetaminophen may lead to serious liver injury. Calcium deregulation, angiotensin II production and xanthine oxidase activity are suggested to play mechanistic roles in such injury.

Objective

This study evaluates the possible protective effects of the calcium channel blocker amlodipine, the angiotensin converting enzyme inhibitor lisinopril, and the xanthine oxidase inhibitor allopurinol against experimental acetaminophen-induced hepatotoxicity, aiming to understand its underlying hepatotoxic mechanisms.

Material and methods

Animals were allocated into a normal control group, a acetaminophen hepatotoxicity control group (receiving a single oral dose of acetaminophen; 750 mg/kg/day), and four treatment groups receive N-acetylcysteine (300 mg/kg/day; a reference standard), amlodipine (10 mg/kg/day), lisinopril (20 mg/kg/day) and allopurinol (50 mg/kg/day) orally for 14 consecutive days prior to acetaminophen administration. Evaluation of hepatotoxicity was performed by the assessment of hepatocyte integrity markers (serum transaminases), oxidative stress markers (hepatic malondialdehyde, glutathione and catalase), and inflammatory markers (hepatic myeloperoxidase and nitrate/nitrite), in addition to a histopathological study.

Results

Rats pre-treated with amlodipine, lisinopril or allopurinol showed significantly lower serum transaminases, significantly lower hepatic malondialdehyde, myeloperoxidase and nitrate/nitrite, as well as significantly higher hepatic glutathione and catalase levels, compared with acetaminophen control rats. Serum transaminases were normalized in the lisinopril treatment group, while hepatic myeloperoxidase was normalized in the all treatment groups. Histopathological evaluation strongly supported the results of biochemical estimations.

Conclusion

Amlodipine, lisinopril or allopurinol can protect against acetaminophen-induced hepatotoxicity, showing mechanistic roles of calcium channels, angiotensin converting enzyme and xanthine oxidase enzyme in the pathogenesis of hepatotoxicity induced by acetaminophen.

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

Aims

In September 2012 the UK’s Commission on Human Medicines (CHM) recommended changes in the management of paracetamol poisoning: use of a single ‘100 mg l⁻¹’ nomogram treatment line, ceasing risk assessment, treating all staggered/uncertain ingestions and increasing the duration of the initial acetylcysteine (NAC) infusion from 15 to 60 min. We evaluated the effect of this on presentation, admission, treatment, adverse reactions and costs of paracetamol poisoning.

Methods

Data were prospectively collected from adult patients presenting to three large UK hospitals from 3 September 2011 to 3 September 2013 (year before and after change). Infusion duration effect on vomiting and anaphylactoid reactions was examined in one centre. A cost analysis from an NHS perspective was performed for 90 000 patients/annum with paracetamol overdose.

Results

There were increases in the numbers presenting to hospital (before 1703, after 1854; increase 8.9% [95% CI 1.9, 16.2], P = 0.011); admitted (1060/1703 [62.2%] vs. 1285/1854 [69.3%]; increase 7.1% [4.0, 10.2], P < 0.001) and proportion treated (626/1703 [36.8%] vs. 926/1854 [50.0%]; increase: 13.2% [95% CI 10.0, 16.4], P < 0.001). Increasing initial NAC infusion did not change the proportion of treated patients developing adverse reactions (15 min 87/323 [26.9%], 60 min 145/514 [28.2%]; increase: 1.3% [95% CI –4.9, 7.5], P = 0.682). Across the UK the estimated cost impact is £8.3 million (6.4 million–10.2 million) annually, with a cost-per-life saved of £17.4 million (13.4 million–21.5 million).

Conclusions

The changes introduced by the CHM in September 2012 have increased the numbers of patients admitted to hospital and treated with acetylcysteine without reducing adverse reactions. A safety and cost-benefit review of the CHM guidance is warranted, including novel treatment protocols and biomarkers in the assessment of poisoning.

Simultaneous determination of acetaminophen and dihydrocodeine in human plasma by UPLC-MS/MS: Its pharmacokinetic application

An ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to determine acetaminophen (AAP) and dihydrocodeine (DHC) in human plasma simultaneously. Plasma samples were prepared using protein precipitation with acetonitrile, the two analytes and the internal standard midazolam were separated on an Acquity UPLC BEH C18 column and mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 151.2→110.0 and m/z 302.3→199.2 were used to quantify for AAP and DHC, respectively. The linearity of this method was found to be within the concentration range of 50-10000ng/mL for AAP, and 1-100ng/mL for DHC in human plasma, respectively. The lower limit of quantification (LLOQ) was 50ng/mL and 1ng/mL for AAP and DHC in human plasma, respectively. The relative standard deviations (RSD) of intra and inter precision were less than 10% for both AAP and DHC. The analysis time of per sample was 1.0min. The developed and validated method was successfully applied to a pharmacokinetic study of AAP (500mg) with DHC (20mg) capsule in Chinese healthy volunteers (N=20).

Aminotriazole alleviates acetaminophen poisoning via downregulating P450 2E1 and suppressing inflammation

Aminotriazole (ATZ) is commonly used as a catalase (CAT) inhibitor. We previously found ATZ attenuated oxidative liver injury, but the underlying mechanisms remain unknown. Acetaminophen (APAP) overdose frequently induces life-threatening oxidative hepatitis. In the present study, the potential hepatoprotective effects of ATZ on oxidative liver injury and the underlying mechanisms were further investigated in a mouse model with APAP poisoning. The experimental data indicated that pretreatment with ATZ dose- and time-dependently suppressed the elevation of plasma aminotransferases in APAP exposed mice, these effects were accompanied with alleviated histological abnormality and improved survival rate of APAP-challenged mice. In mice exposed to APAP, ATZ pretreatment decreased the CAT activities, hydrogen peroxide (H2O2) levels, malondialdehyde (MDA) contents, myeloperoxidase (MPO) levels in liver and reduced TNF-α levels in plasma. Pretreatment with ATZ also downregulated APAP-induced cytochrome P450 2E1 (CYP2E1) expression and JNK phosphorylation. In addition, posttreatment with ATZ after APAP challenge decreased the levels of plasma aminotransferases and increased the survival rate of experimental animals. Posttreatment with ATZ had no effects on CYP2E1 expression or JNK phosphorylation, but it significantly decreased the levels of plasma TNF-α. Our data indicated that the LD50 of ATZ in mice was 5367.4 mg/kg body weight, which is much higher than the therapeutic dose of ATZ in the present study. These data suggested that ATZ might be effective and safe in protect mice against APAP-induced hepatotoxicity, the beneficial effects might resulted from downregulation of CYP2E1 and inhibiton of inflammation.

Worldwide research productivity of paracetamol (acetaminophen) poisoning: a bibliometric analysis (2003-2012)

PURPOSE

There is a lack of data concerning the evaluation of scientific research productivity in paracetamol poisoning from the world. The purposes of this study were to analyse the worldwide research output related to paracetamol poisoning and to examine the authorship pattern and the citations retrieved from the Scopus database for over a decade.

METHODS

Data were searched for documents with specific words regarding paracetamol poisoning as 'keywords' in the title or/and abstract. Scientific output was evaluated based on a methodology developed and used in other bibliometric studies. Research productivity was adjusted to the national population and nominal gross domestic product (GDP) per capita.

RESULTS

There were 1721 publications that met the criteria during study period from the world. All retrieved documents were published from 72 countries. The largest number of articles related to paracetamol poisoning was from the United States (US; 30.39%), followed by India (10.75%) and the United Kingdom (UK; 9.36%). The total number of citations at the time of data analysis was 21,109, with an average of 12.3 citations per each documents and median (interquartile range) of 4 (1-14). The h-index of the retrieved documents was 57. After adjusting for economy and population power, India (124.2), Nigeria (18.6) and the US (10.5) had the highest research productivity. Countries with large economies, such as the UK, Australia, Japan, China and France, tended to rank relatively low after adjustment for GDP over the entire study period.

CONCLUSION

Our study demonstrates evidence that research productivity related to paracetamol poisoning has increased rapidly during the recent years. The US obviously dominated in research productivity. However, certain smaller country such as Nigeria has high scientific output relative to their population size and GDP. A highly noticeable increase in the contributions of Asia-Pacific and Middle East regions to scientific literature related to paracetamol poisoning was also observed.

Acetaminophen hepatotoxicity: an updated review

As the most common cause of acute liver failure (ALF) in the USA and UK, acetaminophen-induced hepatotoxicity remains a significant public health concern and common indication for emergent liver transplantation. This problem is largely attributable to acetaminophen combination products frequently prescribed by physicians and other healthcare professionals, with unintentional and chronic overdose accounting for over 50 % of cases of acetaminophen-related ALF. Treatment with N-acetylcysteine can effectively reduce progression to ALF if given early after an acute overdose; however, liver transplantation is the only routinely used life-saving therapy once ALF has developed. With the rapid course of acetaminophen-related ALF and limited supply of donor livers, early and accurate diagnosis of patients that will require transplantation for survival is crucial. Efforts in developing novel treatments for acetaminophen-induced ALF are directed toward bridging patients to recovery. These include auxiliary, artificial, and bioartificial support systems. This review outlines the most recent developments in diagnosis and management of acetaminophen-induced ALF.