Severe hepatotoxicity after therapeutic doses of acetaminophen

Drug-drug interaction assessment based on a large-scale spontaneous reporting system for hepato- and renal-toxicity, and thrombocytopenia with concomitant low-dose methotrexate and analgesics use

BACKGROUND

Methotrexate (MTX) is the cornerstone of rheumatoid arthritis (RA) treatment and is highly effective with low-dose intermittent administration. MTX is occasionally used in combination with non-steroidal anti-inflammatory drugs (NSAIDs) and acetaminophen (APAP)/paracetamol for pain or inflammation control. With MTX treatment, the side effects, such as hepatotoxicity, renal failure, and myelosuppression should be considered. These are also seen with analgesics treatment.

METHODS

We used a large spontaneously reported adverse event database (FAERS [JAPIC AERS]) to analyze whether the reporting of adverse events increased upon MTX and analgesic therapy in patients with RA.

RESULTS

After identifying RA cases, the crude reporting odds ratios (cRORs) for hepatotoxicity, renal failure, and thrombocytopenia associated with the use of MTX, APAP, or NSAIDs were calculated by disproportionality analysis, which revealed significantly higher cRORs for these events. No analgesics showed consistent positive signals for drug-drug interaction (DDI) with concomitant low-dose MTX analyzed using four algorithms for DDI interaction (the Ω shrinkage measure, additive or multiplicative, and combination risk ratio models). However, in renal failure and thrombocytopenia, loxoprofen (Ω025 = 0.08) and piroxicam (Ω025 = 0.46), and ibuprofen (Ω025 = 0.74) and ketorolac (Ω025 = 3.52), respectively, showed positive signals in the Ω shrinkage measure model, and no consistency was found among adverse events or NSAIDs.

CONCLUSIONS

Studies using spontaneous reporting systems have limitations such as reporting bias or lack of patient background; however, the results of our comprehensive analysis support the results of previous clinical or epidemiological studies. This study also demonstrated the usefulness of FAERS for DDI assessment.

A Case of Significant Transaminitis with Liver Biopsy in a Pregnant Patient with COVID-19

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, has led to a global health crisis. The virus can cause varying severity of liver injury, but the mechanism has not yet been elucidated, especially in pregnancy. We present a morbidly obese 30-year-old woman with COVID-19 at 28 weeks' gestation complicated by significant transaminitis with peak liver enzymes levels of 501/1,313 (aspartate aminotransferase/alanine aminotransferase). Liver biopsy showed reactive changes consistent with medication effect and mild steatosis. Significant transaminitis has been found in both pregnant and nonpregnant patients with COVID-19. Our case demonstrates the multifactorial nature of liver injury in COVID-19 patients including mild underlying liver steatosis combined with possible viral potentiation of medication effect.

The Role of Glutathione in Selected Viral Diseases

During inflammatory processes, immunocompetent cells are exposed to substantial amounts of free radicals and toxic compounds. Glutathione is a cysteine-containing tripeptide that is an important and ubiquitous antioxidant molecule produced in human organs. The intracellular content of GSH regulates the detoxifying capacity of cells, as well as the inflammatory and immune response. GSH is particularly important in the liver, where it serves as the major non-protein thiol involved in cellular antioxidant defense. There are numerous causes of hepatitis. The inflammation of the liver can be caused by a variety of infectious viruses. The relationship between oxidative stress and the hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis E virus (HEV) infection is not fully known. The aim of this study was to examine the relationship between hepatotropic viruses and glutathione status, including reduced glutathione (GSH) and oxidized glutathione (GSSG), as well as antioxidant enzymes, e.g., glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) in liver diseases.

PIWI-interacting RNA-23210 protects against acetaminophen-induced liver injury by targeting HNF1A and HNF4A

Acetaminophen (APAP) overdose is one of the leading causes of acute liver failure in the US and other developed countries, the molecular mechanisms of APAP-induced hepatotoxicity remain speculative. PIWI-interacting RNAs (piRNAs), a novel class of small non-coding RNAs, have been identified as epigenetic regulators of transposon silencing, mRNA deadenylation, and elimination. However, the functional role of piRNAs in APAP-induced liver injury remains unclear. In the current study, the piRNA profiles were constructed in HepaRG cells after APAP exposure, and the roles of piR-23210 in regulating nuclear receptors (NRs) expression, metabolizing enzymes expression, and consequently APAP-induced liver injury were systematically investigated. As a result, 57 upregulated piRNAs were identified after APAP exposure, indicating the stress-response characteristic of piRNA molecules. Subsequent in vitro and in vivo experiments proved that piR-23210 is a novel self-protective molecule that targets HNF1A and HNF4A transcripts by interacting with RNA binding protein Nucleolin (NCL), suppresses downstream CYPs (CYP2E1, CYP3A4, and CYP1A2) expression, and protects against APAP-induced liver injury. In conclusion, our findings provided new mechanistic clues revealing potential protective role of a piRNA against the hepatoxicity of APAP.

N-acetylcysteine prevents glutathione decrease and does not interfere with paracetamol antinociceptive effect at therapeutic dosage: a randomized double-blind controlled trial in healthy subjects

Paracetamol (APAP) may lead to hepatic changes even at therapeutic dosages. Glutathione (GSH) plays a pivotal role in APAP metabolism as it allows the detoxification of a toxic metabolite. N-Acetylcysteine (NAC) is APAP antidote, is also largely used as a mucoactive drug and is often associated with APAP. This study aims at evaluating if 1- NAC modifies APAP pain efficacy and 2- NAC prevents glutathione depletion with APAP at therapeutic doses. This double-blind randomized controlled study (NCT02206178) was carried out in 24 healthy volunteers. APAP was given for 4 days (1 g ×4 daily) with NAC or with placebo. Thermal pain tests, whole blood GSH, and hepatic enzymes (ASAT, ALAT) were measured before (D0) and after (D4) oral APAP-NAC or APAP-placebo intake. anova for repeated measures adapted to cross-overdesign was performed and a two-tailed type I error was fixed at 5%. The primary endpoint was the area under the curve (0-240 min) of pain intensity (Numerical Scale) after thermal pain stimulation using Pathway-Medoc^® . APAP antinociceptive effect was similar in both groups. GSH was maintained to its baseline value in the APAP/NAC group but diminished in the APAP/placebo group (P = 0.033). This study shows for the first time that APAP antinociceptive effectiveness is not influenced by NAC. It also shows that the effect of APAP at therapeutic dosage on GSH may be counteracted by NAC. These issues are particularly important for patients as APAP is often prescribed for years as a first-line pain treatment and further trials in patients are now warranted.

What dose of paracetamol for older people?

Paracetamol, on its own or in combination with other analgesics, is widely used to treat pain associated with acute and chronic conditions. It is considered safe enough to have a general sales licence (GSL) for use by "adults, elderly and children over 16 years" and has few listed cautions or contraindications.1,2 However, recently the effectiveness and safety of paracetamol for some conditions have been challenged, 3,4 and there are published case reports of liver failure associated with therapeutic doses.5-9 Here, we review the use of paracetamol, its pharmacokinetics, the mechanisms by which it can cause liver damage and consider whether frail older people are at greater risk of adverse effects. We also discuss if dose reduction should be considered in some circumstances.

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

Purpose

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

Method

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

Results

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

Conclusion

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

Electronic supplementary material

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

Cobalt chloride exposure dose-dependently induced hepatotoxicity through enhancement of cyclooxygenase-2 (COX-2)/B-cell associated protein X (BAX) signaling and genotoxicity in Wistar rats

Cobalt chloride (CoCl₂ ) is one of the many environmental contaminants, used in numerous industrial sectors. It is a pollutant with deadly toxicological consequences both in developing and developed countries. We investigated toxicological impact of CoCl₂ on hepatic antioxidant status, apoptosis, and genotoxicity. Forty Wistar rats were divided into four groups, 10 rats per group: Group 1 served as control and received clean tap water orally; Group 2 received CoCl₂ solution (150 mg/L); Group 3 received CoCl₂ solution (300 mg/L); and Group 4 received CoCl₂ (600 mg/L) in drinking water for 7 days, respectively. Exposure of rats to CoCl₂ led to a significant decline in hepatic antioxidant enzymes together with significant increase in markers of oxidative stress. Immunohistochemistry revealed dose-dependent increase in cyclooxygenase-2 and BAX expressions together with increased frequency of Micronucleated Polychromatic Erythrocytes. Combining all, CoCl₂ administration led to hepatic damage through induction of oxidative stress, inflammation, and apoptosis.

Aging with HIV in the ART era

In the current era of therapy for human immunodeficiency virus (HIV), life expectancy for persons living with HIV (PLWH) approaches that of the general population. This newly prolonged survival among PLWH is associated with an increased prevalence of comorbidities due to the inflammation, immune activation and immune senescence associated with HIV infection. Higher prevalence of tobacco and alcohol use, co-infection with viral hepatitis and traditional cardiovascular risk factors such as hypertension and hyperlipidemia contribute as well. In this review, we hope to describe the current comorbidities occurring among PLWH and bring increased awareness for conditions that may otherwise not be considered given the younger age at time of presentation.

[Prescription of acetaminophen in five French hospitals: What are the practices?]

AIM

Acetaminophen is widely used in hospital settings and often considered as nontoxic. We conducted a multicentric study in order to evaluate its proper use.

METHOD

Prescriptions from five general hospitals were analyzed, according to dose adjustments required in renal or liver failure, weight or chronic alcoholism, determined using a literature review. Other criteria have been assessed: indication for parenteral access, accuracy of administration time and pain assessment.

RESULTS

Among the 1256 analyzed prescriptions, 21% are non-compliants. The main causes of non-compliance (NC) are adjustments to weight and renal failure. Higher NC rates concern chronic alcoholism and liver failure.

CONCLUSION

Misuse of acetaminophen seems related to a lack of official recommendations concerning dose adjustments. Hospital pharmacists have an important role to play in the promotion of proper use of acetaminophen. Therefore we established a prescribing aid.

Antioxidant and Hepatoprotective Efficiency of Selenium Nanoparticles Against Acetaminophen-Induced Hepatic Damage

Overdoses of acetaminophen (APAP), a famous and widely used drug, may have hepatotoxic effects. Nanoscience is a novel scientific discipline that provides specific tools for medical science problems including using nano trace elements in hepatic diseases. Our study aimed to assess the hepatoprotective role of selenium nanoparticles (Nano-Se) against APAP-induced hepatic injury. Twenty-four male rats were classified into three equal groups: a control group that received 0.9 % NaCl, an APAP-treated group (oral administration), and a group treated with Nano-Se (10-20 nm, intraperitoneal (i.p.) injection) and APAP (oral administration). APAP overdose induced significant elevations in liver function biomarkers, hepatic lipid peroxidation, hepatic catalase, and superoxide dismutase (SOD), decreased the reduced glutathione (GSH) content and glutathione reductase (GR) activity, and stimulated significant DNA damage in hepatocytes, compared to control rats. Nano-Se administration improved the hepatic antioxidant protection mechanism and decreased cellular sensitivity to DNA fragmentation. Nano-Se exhibits a protective effect against APAP-induced hepatotoxicity through improved liver function and oxidative stress mediated by catalase, SOD, and GSH and decreases hepatic DNA fragmentation, a hepatic biomarker of cell death. Nano-Se could be a novel hepatoprotective strategy to inhibit oxidative stress.

Intravascular large B-cell lymphoma associated with silicone breast implant, HLA-DRB1*11:01, and HLA-DQB1*03:01 manifesting as macrophage activation syndrome and with severe neurological symptoms: a case report

BACKGROUND

Silicone implants have been successfully used for breast augmentation and reconstruction in millions of women worldwide. The reaction to the silicone implant is highly variable; it can lead to local inflammatory symptoms, and sometimes to systemic symptoms and disease. Over 80 cases of anaplastic lymphoma kinase-negative anaplastic large cell lymphoma have been reported in patients with silicone breast implants and have been accepted as a new clinical entity. To the best of our knowledge, an intravascular large B-cell lymphoma associated with a silicone breast implant has not been reported previously.

CASE PRESENTATION

A 48-year-old Caucasian woman who presented with high fever was found to have splenomegaly on physical examination. A laboratory diagnosis revealed pancytopenia, hypertriglyceridemia, and hyperferritinemia. She developed signs of altered sensorium, hemiparesis, aphasia, and cauda equina syndrome. On further evaluation, she fulfilled the necessary five out of eight criteria for diagnosis of macrophage activation syndrome/hemophagocytic lymphohistiocytosis. Dexamethasone administration was followed by prompt improvement; however, 3 days later she again manifested high fever, which persisted despite administration of immunoglobulin and cyclosporine A. Her silicone breast implant was considered a possible contributor to her macrophage activation syndrome and was therefore removed. A histological examination of the capsule tissue showed an extensive lymphohistiocytic/giant cell foreign body reaction suggestive of autoimmune/inflammatory syndrome induced by adjuvants. However, the histological examination unexpectedly also revealed an intravascular large B-cell lymphoma.

CONCLUSIONS

The genetic background of our patient with silicone breast implants might have predisposed her to three rare and difficult to diagnose syndromes/diseases: macrophage activation syndrome/hemophagocytic lymphohistiocytosis, autoimmune/inflammatory syndrome induced by adjuvants, and intravascular large B-cell lymphoma. The simultaneous manifestation of all three syndromes suggests causal interrelationships. Human leukocyte antigen testing in all women who undergo silicon breast implantation could in the future enable us to better evaluate the risk of potential side effects.

The protective effect of pomegranate juice in paracetamol-induced acute hepatotoxicity in rats

AIM

Being the most commonly used antipyretic and analgesic, paracetamol is one of the most common causes of childhood poisoning in the world and maintains its importance also in our country. Paracetamol poisoning is one of the most common causes of liver failure. This study aimed to investigate if pomegranate juice had protective effect in acute liver toxicity related with paracetamol.

MATERIAL AND METHODS

A total of 36 Wistar-Albino rats were divided into four groups as the paracetamol group (3 000 mg/kg paracetamol), the pomegranate juice + paracetamol group (1.5 mL pomegranate juice plus 3 000 mg/kg paracetamol), the pomegranate juice group (1.5 mL pomegranate juice) and the control group (1.5 mL distilled water). Pomegranate juice and distilled water were administered for eight days. Paracetamol was administered on day 8. The level of thiobarbituric acid reactive substances, as an oxidative marker, was measured in the blood and liver tissue on day 9. In addition, liver tissues were evaluated histologically (in terms of increased connective tissue, granular degeneration, mononuclear cell infiltration, necrotic cells and vascular congestion).

RESULTS

The liver tissue and blood thiobarbituric acid reactive substances levels were found to be significantly lower in the pomegranate juice + paracetamol group compared to the paracetamol group (p<0.05). Histologically, structural changes related with damage were observed in both the paracetamol group and pomegranate juice + paracetamol group. The extent of damage was statistically significantly lower in the pomegranate juice + paracetamol group (p<0.001).

CONCLUSIONS

Our results related with oxidative and histologic evaluation showed that pomegranate juice might have a preventive effect in paracetamol-induced acute liver damage.

Faut-il contrôler la fièvre dans les infections sévères ?

Le contrôle de la fièvre lors des sepsis graves est couramment utilisé en réanimation, respectivement dans 66 et 70 % des états septiques graves et des chocs septiques. Pourtant, les preuves formelles quant au bénéfice d’une telle stratégie manquent. On peut s’interroger à la lumière de travaux expérimentaux parfois anciens et d’études observationnelles plus récentes des risques d’un contrôle sur le cours évolutif de l’infection, le devenir du patient, ainsi que sur l’innocuité des traitements appliqués pour obtenir le contrôle. Néanmoins, dans certaines situations, la fièvre peut être délétère, en lien avec une consommation en oxygène (O₂) accrue et le risque d’ischémie tissulaire et/ou une réaction inflammatoire focale exacerbée. Chez des patients septiques, le contrôle de la fièvre fait appel à des moyens physiques (refroidissement externe et/ou interne) et/ou pharmacologiques (essentiellement le paracétamol et/ou des anti-inflammatoires non stéroïdiens). Malgré les incertitudes quant au bénéfice ou non à contrôler la température, il faut certainement s’affranchir des températures extrêmes (hypoou hyperthermie) et évaluer individuellement le rapport bénéfice/risque.

[Clinical pharmacist influence at hospital to prevent overdosed prescription of acetaminophen]

OBJECTIVES

The recommended daily dose of acetaminophen is limited to 60mg/kg/day with a maximum of 3g daily dose in adults weighing less than 50kg or in patients undergoing certain risk factors. This study aimed at assessing the fulfillment of those recommendations and the possible impact on the liver dysfunction at supra-therapeutic doses of acetaminophen.

METHODS

This study was performed one day in 9 services. Patients characteristics, acetaminophen dose, daily dose administered, physiopathological aspects, markers of liver damage were collected.

RESULTS

Among 542 prescriptions analyzed, 343 of them contained acetaminophen. The median age of patients studied was 81 years and one third weighed less than 50kg. The main risk factor of supra-therapeutic prescriptions was the lack of dose acetaminophen based on weight with 14% patients concerned and this risk raised at 17% when the pathophysiological conditions were included. The presence of pharmacists in medicals departments was more effective than the use of informatics programs limiting the dose systematically to 3g/day, or a distant pharmaceutical validation from care services to reduce the risk of acetaminophen overdose. According to the statement of administrations, only 4 of 49 patients received doses above 60mg/kg/day with a low impact on liver function tests.

CONCLUSION

The continuous presence in pharmaceutical care services was the most effective measure to ensure effective implementation of acetaminophen recommendations.

Can paracetamol (acetaminophen) be administered to patients with liver impairment?

Although 60 years have passed since it became widely available on the therapeutic market, paracetamol dosage in patients with liver disease remains a controversial subject. Fulminant hepatic failure has been a well documented consequence of paracetamol overdose since its introduction, while short and long term use have both been associated with elevation of liver transaminases, a surrogate marker for acute liver injury. From these reports it has been assumed that paracetamol use should be restricted or the dosage reduced in patients with chronic liver disease. We review the factors that have been purported to increase risk of hepatocellular injury from paracetamol and the pharmacokinetic alterations in different pathologies of chronic liver disease which may affect this risk. We postulate that inadvertent under-dosing may result in concentrations too low to enable efficacy. Specific research to improve the evidence base for prescribing paracetamol in patients with different aetiologies of chronic liver disease is needed.

The purine analogues abacavir and didanosine increase acetaminophen-induced hepatotoxicity by enhancing mitochondrial dysfunction

BACKGROUND

NRTIs are essential components of HIV therapy with well-documented, long-term mitochondrial toxicity in hepatic cells, but whose acute effects on mitochondria are unclear. As acetaminophen-induced hepatotoxicity also involves mitochondrial interference, we hypothesized that it would be exacerbated in the context of ART.

METHODS

We evaluated the acute effects of clinically relevant concentrations of the most widely used NRTIs, alone or combined with acetaminophen, on mitochondrial function and cellular viability.

RESULTS

The purine analogues abacavir and didanosine produced an immediate and concentration-dependent inhibition of oxygen consumption and complex I and III activity. This inhibition was accompanied by an undermining of mitochondrial function, with increased production of reactive oxygen species and reduction of mitochondrial membrane potential and intracellular ATP levels. However, this interference did not compromise cell survival. Co-administration with concentrations of acetaminophen below those considered hepatotoxic exacerbated the deleterious effects of both compounds on mitochondrial function and compromised cellular viability, showing a clear correlation with diminished glutathione levels.

CONCLUSIONS

The simultaneous presence of purine analogues and low concentrations of acetaminophen significantly potentiates mitochondrial dysfunction, increasing the risk of liver injury. This new mechanism is relevant given the liver's susceptibility to mitochondrial dysfunction-related toxicity and the tendency of the HIV infection to increase oxidative stress.

Risk of Acute Kidney Injury and Long-Term Outcome in Patients With Acetaminophen Intoxication: A Nationwide Population-Based Retrospective Cohort Study

Acetaminophen (APAP) intoxication is a common cause of hepatic toxicity and life-threatening hepatic failure. However, few studies have investigated the possible association between APAP intoxication and acute kidney injury (AKI). We constructed a retrospective cohort study to clarify the relationship between APAP intoxication and the risk of AKI.We identified patients with APAP intoxication and selected a comparison cohort that was 1:4 frequency matched according to age, sex, and year of APAP intoxication diagnosis from the Taiwan National Health Insurance Research Database from 1998 to 2010. We analyzed the risks of AKI for patients with APAP intoxication by using Cox proportional hazards regression models.In this study, 2914 patients with APAP intoxication and 11,656 controls were included. The overall risks of developing AKI were 2.41-fold in the patients with APAP intoxication compared with the comparison cohort. After we excluded APAP intoxication patients with coexisting AKI and hepatic failure/hepatitis, the overall risks of developing AKI were still 2.22-fold in the patients with APAP intoxication. There were 2 patients who had end-stage renal disease (ESRD) following APAP intoxication-related AKI. Limitations include retrospective review, selection bias, and absence of data on detail medications used, laboratory investigations and dosage of APAP intoxication.Our long-term cohort study results showed that AKI is a possible adverse effect among patients with APAP intoxication, regardless of whether patients have presented with hepatic toxicity. However, additional studies are necessary to clarify whether such patients can progress to ESRD.

Protective effect of Baccharis trimera extract on acute hepatic injury in a model of inflammation induced by acetaminophen

BACKGROUND

Acetaminophen (APAP) is a commonly used analgesic and antipyretic. When administered in high doses, APAP is a clinical problem in the US and Europe, often resulting in severe liver injury and potentially acute liver failure. Studies have demonstrated that antioxidants and anti-inflammatory agents effectively protect against the acute hepatotoxicity induced by APAP overdose.

METHODS

The present study attempted to investigate the protective effect of B. trimera against APAP-induced hepatic damage in rats. The liver-function markers ALT and AST, biomarkers of oxidative stress, antioxidant parameters, and histopathological changes were examined.

RESULTS

The pretreatment with B. trimera attenuated serum activities of ALT and AST that were enhanced by administration of APAP. Furthermore, pretreatment with the extract decreases the activity of the enzyme SOD and increases the activity of catalase and the concentration of total glutathione. Histopathological analysis confirmed the alleviation of liver damage and reduced lesions caused by APAP.

CONCLUSIONS

The hepatoprotective action of B. trimera extract may rely on its effect on reducing the oxidative stress caused by APAP-induced hepatic damage in a rat model. General Significance. These results make the extract of B. trimera a potential candidate drug capable of protecting the liver against damage caused by APAP overdose.

Acetaminophen increases the risk of arsenic-mediated development of hepatic damage in rats by enhancing redox-signaling mechanism

We evaluated whether the commonly used analgesic-antipyretic drug acetaminophen can modify the arsenic-induced hepatic oxidative stress and also whether withdrawal of acetaminophen administration during the course of long-term arsenic exposure can increase susceptibility of liver to arsenic toxicity. Acetaminophen was co-administered orally to rats for 3 days following 28 days of arsenic pre-exposure (Phase-I) and thereafter, acetaminophen was withdrawn, but arsenic exposure was continued for another 28 days (Phase-II). Arsenic increased lipid peroxidation and reactive oxygen species (ROS) generation, depleted glutathione (GSH), and decreased superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and glutathione reductase (GR) activities. Acetaminophen caused exacerbation of arsenic-mediated lipid peroxidation and ROS generation and further enhancement of serum alanine aminotransferase and aspartate aminotransferase activities. In Phase-I, acetaminophen caused further GSH depletion and reduction in SOD, catalase, GPx and GR activities, but in Phase-II, only GPx and GR activities were more affected. Arsenic did not alter basal and inducible nitric oxide synthase (iNOS)-mediated NO production, but decreased constitutive NOS (cNOS)-mediated NO release. Arsenic reduced expression of endothelial NOS (eNOS) and iNOS genes. Acetaminophen up-regulated eNOS and iNOS expression and NO production in Phase-I, but reversed these effects in Phase-II. Results reveal that acetaminophen increased the risk of arsenic-mediated hepatic oxidative damage. Withdrawal of acetaminophen administration also increased susceptibility of liver to hepatotoxicity. Both ROS and NO appeared to mediate lipid peroxidation in Phase-I, whereas only ROS appeared responsible for peroxidative damage in Phase-II.

Acetaminophen receipt among HIV-infected patients with advanced hepatic fibrosis

PURPOSE

HIV-infected patients may be at particular risk for acetaminophen-induced hepatotoxicity, but acetaminophen use in the context of liver injury has been incompletely examined among HIV-infected patients. Among a sample of HIV-infected patients, we aimed to determine acetaminophen exposure, assess the cross-sectional association between acetaminophen exposure and advanced hepatic fibrosis, and determine whether factors associated with acetaminophen exposure varied by HCV status.

METHODS

We conducted a cross-sectional analysis of the Veterans Aging Cohort Study. Advanced hepatic fibrosis was defined as a FIB-4 > 3.25, a composite score calculated based on age, alanine aminotransferase, aspartate aminotransferase, and platelet count. Multivariable ordered polytomous logistic regression was used to determine the association between FIB-4 status and acetaminophen exposure stratified by HCV status.

RESULTS

Among HIV-infected patients (n = 14 885), 31% received at least one acetaminophen prescription. Among those receiving acetaminophen, acetaminophen overuse was common among both HIV-monoinfected and HIV/HCV-coinfected patients (846 [31%] vs 596[32%], p = 0.79). After stratifying by HCV status, those with evidence of advanced liver fibrosis were equally likely to be exposed to acetaminophen. Furthermore, HIV-monoinfected patients with an alcohol use disorder were more likely to have acetaminophen overuse (OR [95%CI] = 1.56 [1.21-2.02]).

CONCLUSIONS

Strategies to minimize acetaminophen exposure, especially for HIV-monoinfected patients, are warranted.

Treatment of DIHS/DRESS syndrome with combined N-acetylcysteine, prednisone and valganciclovir--a hypothesis

Background

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS) is a rare and severe adverse drug reaction with an associated mortality of 10–20%. Clinical worsening despite discontinuation of the culprit drug is considered a characteristic feature of DIHS/DRESS. Besides the early recognition of the syndrome and discontinuation of its causative drug, the mainstay of treatment is systemic corticosteroids. Nevertheless, treatment of severe DIHS/DRESS is not well defined, as corticosteroids may sometimes not be effective, and decreasing the dose may be associated with flaring of the disease.

Case Report

A 38-year-old woman with high fever, malaise, abdominal pain, rash, and elevated liver enzymes received immediate high-dose N-acetylcysteine, because acetaminophen hepatotoxicity was suspected. N-acetylcysteine administration was associated with a significant clinical improvement. However, within the next week DIHS/DRESS syndrome was diagnosed, which explained all the symptoms, and which was subsequently treated with prednisone and valganciclovir.

Conclusions

New options necessary to improve treatment of severe DIHD/DRESS have to consider its sequential pathogenetic mechanisms. N-acetylcysteine might neutralize the drug-derived reactive metabolites, which are responsible for protein adduct formation and specific T cell stimulation, and replete the glutathione stores that counterbalance oxidative stress. Prednisone might inhibit lymphoproliferation and valganciclovir might prevent complications related to HHV-6 reactivation. We therefore propose the unprecedented combination of N-acetylcysteine, prednisone and valganciclovir as a treatment option for DIHS/DRESS.

Overdosed prescription of paracetamol (acetaminophen) in a teaching hospital

INTRODUCTION

Paracetamol is the most commonly used analgesic and antipyretic. Reviews of hospital use of paracetamol are scarce. Little is known about the appropriateness of the dose of paracetamol prescribed for hospitalized adults. The aim of this study was to report on the nature and the frequency of the overdosed prescription of paracetamol observed in adult patients over a 4.5-year period in a teaching hospital.

METHODS

Prescription analysis by pharmacists was performed once a week in six medical and three surgical departments and daily in a post-emergency unit. In cases of prescription error, the pharmacist notified the physician through an electronic alert when a computerized prescription order entry system was available or otherwise by face-to-face discussion. For each drug-related problem detected, the pharmacists recorded relevant details in a database.

RESULTS

From October 2006 to April 2011, 44,404 prescriptions were reviewed and 480 alerts related to the overdosed prescription of paracetamol were made (1% of analyzed prescriptions). The extent of errors of dosage was within the intervals [90-120 mg/kg/d] and greater than 120 mg/kg/d for 87 and 11 patients respectively, who were prescribed a single non-combination paracetamol containing product. Sixty alerts concerned co-prescription of at least two paracetamol containing products with similar frequency for computerized (1.4/1000) or handwritten (1.2/1000) prescriptions.

DISCUSSION

Prescriptions of paracetamol for hospitalized adults frequently exceed the recommended dosage.

CONCLUSION

These results highlight the need for increased awareness of unintentional paracetamol overdose and support the initiation of an educational program aimed at physicians and nurses.

Population prevalence of high dose paracetamol in dispensed paracetamol/opioid prescription combinations: an observational study

Background

Paracetamol (acetaminophen) is generally considered a safe medication, but is associated with hepatotoxicity at doses above doses of 4.0 g/day, and even below this daily dose in certain populations.

Methods

The Nova Scotia Prescription Monitoring Program (NSPMP) in the Canadian province of Nova Scotia is a legislated organization that collects dispensing information on all out-of-hospital prescription controlled drugs dispensed for all Nova Scotia residents. The NSPMP provided data to track all paracetamol/opioids redeemed by adults in Nova Scotia, from July 1, 2005 to June 30, 2010. Trends in the number of adults dispensed these prescriptions and the numbers of prescriptions and tablets dispensed over this period were determined. The numbers and proportions of adults who filled prescriptions exceeding 4.0 g/day and 3.25 g/day were determined for the one-year period July 1, 2009 to June 30, 2010. Data were stratified by sex and age (<65 versus 65+).

Results

Both the number of prescriptions filled and the number of tablets dispensed increased over the study period, although the proportion of the adult population who filled at least one paracetamol/opioid prescription was lower in each successive one-year period. From July 2009 to June 2010, one in 12 adults (n = 59,197) filled prescriptions for over 13 million paracetamol/opioid tablets. Six percent (n = 3,786) filled prescriptions that exceeded 4.0 g/day and 18.6% (n = 11,008) exceeded 3.25 g/day of paracetamol at least once. These findings exclude non-prescription paracetamol and paracetamol–only prescribed medications.

Conclusions

A substantial number of individuals who redeem prescriptions for paracetamol/opioid combinations may be at risk of paracetamol-related hepatotoxicity. Healthcare professionals must be vigilant when prescribing and dispensing these medications in order to reduce the associated risks.

A review of the evidence concerning hepatic glutathione depletion and susceptibility to hepatotoxicity after paracetamol overdose

Paracetamol (acetaminophen) poisoning is common throughout the world. The management of nonstaggered (acute) paracetamol overdose is based on the plasma paracetamol concentration plotted on a treatment nomogram. In the UK there are two treatment lines on this nomogram, with the lower treatment line used for individuals felt to be at ‘high risk’ of paracetamol-related hepatotoxicity either as a result of induction of cytochrome P450 isoenzymes or reduction of intrahepatic glutathione. In this article we review the risk factors that, in current guidelines, are felt to increase risk due to a reduction in intrahepatic glutathione concentrations. Based on our review of the published literature, we feel that cystic fibrosis, acute viral illness, malnutrition, and eating disorders such as anorexia nervosa are likely to be associated with reduction in intrahepatic glutathione concentrations, and that this risk is likely to be related to malnutrition secondary to the disease. Chronic hepatitis C infection is also associated with reduced glutathione concentrations, although this appears to be independent of any associated malnutrition. Ageing and acute fasting are not associated with an increased risk of paracetamol-related hepatotoxicity due to reductions in glutathione concentrations. Finally, the evidence for HIV infection is inconclusive, particularly as the majority of studies were conducted in the pre-anti-viral treatment (HAART) era; however it is likely that patients with symptomatic HIV/AIDS have reduced glutathione concentrations due to associated malnutrition. Although there have been few studies which have specifically investigated whether there is an association between reduced intrahepatic glutathione concentrations and increased risk of paracetamol-related hepatotoxicity, in our opinion, it is likely that the above conditions that are associated with reduced glutathione concentrations, will be associated with an increased risk of paracetamol-related hepatotoxicity.

Aminotransferase Levels in Relation to Short-Term use of Acetaminophen Four Grams Daily in Postoperative Cardiothoracic Patients in the Intensive Care Unit

A volunteer study suggested that taking paracetamol 4 g daily could result in elevated alanine aminotransferase plasma levels in a substantial proportion of healthy volunteers. The safety of this dose of paracetamol for acute postoperative pain remains controversial. This study aimed to examine the incidence of alanine aminotransferase elevations after short-term use of paracetamol 4 g daily, as part of the standard pain management protocol, for 93 consecutive patients after cardiothoracic surgery. Alanine aminotransferase levels and other liver function tests were measured preoperatively as baseline and once daily after surgery during the intensive care unit stay. Preoperative alanine aminotransferase levels of more than one time the upper limit of normal (ULN, >40 U/l) was observed in 11% (n=10) of the patients but none of these baseline alanine aminotransferase levels exceeded three times the ULN (>3×ULN). The average daily dose of paracetamol administered was 50 mg/kg (SD=16) after surgery. Postoperative alanine aminotransferase levels of >1×ULN was observed in 17% (n=16), and 4% (n=4) exceeded >3×ULN. The other liver function tests of the latter four patients, including aspartate aminotransferase (range 173 to 5590 U/l), γ-glutamyltransferase (range 56 to 103 U/l), lactate dehydrogenase (range 376 to 3518 U/l) and the International Normalised Ratio (range 2.0 to 6.6), were all abnormal. These four patients all had right ventricular failure or cardiogenic shock during the postoperative period which could explain the significant rises in alanine aminotransferase after surgery. In conclusion, the incidence of significant alanine aminotransferase elevations after using daily paracetamol as an analgesic agent for cardiac surgery, at a dose of 4 g per day, was low and mostly due to complications after surgery. Our results, albeit still very limited, provided some reassurance about the safety of paracetamol 4 g daily, as a supplementary analgesic agent for adult patients undergoing cardiac surgery.

Paracetamol in therapeutic dosages and acute liver injury: causality assessment in a prospective case series

Background

Acute liver injury (ALI) induced by paracetamol overdose is a well known cause of emergency hospital admission and death. However, there is debate regarding the risk of ALI after therapeutic dosages of the drug.

The aim is to describe the characteristics of patients admitted to hospital with jaundice who had previous exposure to therapeutic doses of paracetamol. An assessment of the causality role of paracetamol was performed in each case.

Methods

Based on the evaluation of prospectively gathered cases of ALI with detailed clinical information, thirty-two cases of ALI in non-alcoholic patients exposed to therapeutic doses of paracetamol were identified. Two authors assessed all drug exposures by using the CIOMS/RUCAM scale. Each case was classified into one of five categories based on the causality score for paracetamol.

Results

In four cases the role of paracetamol was judged to be unrelated, in two unlikely, and these were excluded from evaluation. In seven of the remaining 26 cases, the RUCAM score associated with paracetamol was higher than that associated with other concomitant medications. The estimated incidence of ALI related to the use of paracetamol in therapeutic dosages was 0.4 per million inhabitants older than 15 years of age and per year (99%CI, 0.2-0.8) and of 10 per million paracetamol users-year (95% CI 4.3-19.4).

Conclusions

Our results indicate that paracetamol in therapeutic dosages may be considered in the causality assessment in non-alcoholic patients with liver injury, even if the estimated incidence of ALI related to paracetamol appears to be low.

Clinical review: fever in septic ICU patients--friend or foe?

In recent years, fever control in critically ill patients by medications and/or external cooling has gained widespread use, notably in patients suffering from neurological injuries. Nevertheless, such a strategy in septic patients is not supported by relevant data. Indeed, in response to sepsis, experimental and clinical studies argue that fever plays a key role in increasing the clearance of microorganisms, the immune response and the heat shock response. Moreover, fever is a cornerstone diagnostic sign in clinical practice, which aids in early and appropriate therapy, and allows physicians to follow the infection course. After discussing the physiological aspects of fever production, the present review aims to delineate the advantages and drawbacks of fever in septic patients. Finally, the treatment of fever by pharmacological and/or physical means is discussed with regards to their drawbacks, which argues for their careful use in septic patients in the absence of clinical relevance.

Relative bioavailability of generic and branded acetylcysteine effervescent tablets: A single-dose, open-label, randomized-sequence, two-period crossover study in fasting healthy Chinese male volunteers

BACKGROUND

Acetylcysteine may be used as a muco- lytic agent for the treatment of chronic bronchitis, chronic obstructive pulmonary disease, and other pulmonary diseases complicated by the production of viscous mucus. However, little is known of its pharmacokinetic properties when given orally in healthy volunteers, particularly in a Chinese Han population. This study was conducted to provide support for the marketing of a generic product in China.

OBJECTIVE

The purpose of this study was to compare the pharmacokinetics and relative bioavailability of a generic test formulation and a branded reference formulation of acetylcysteine in fasting healthy Chinese male volunteers.

METHODS

A single-dose, open-label, randomized-sequence, 2-period crossover design with a 7-day washout period between doses was used in this study. Healthy Chinese male nonsmokers aged 18 to 40 years with a body mass index (BMI) of 19 to 25 kg/m(2) were selected. Eligible volunteers were randomly assigned to receive acetylcysteine 600 mg PO as either the test formulation (3 tablets of 200 mg each) or reference formulation (1 tablet of 600 mg) under fasting conditions. A total of 15 serial blood samples were collected over a 24-hour interval, and total plasma acetylcysteine concentrations were analyzed by a validated liquid chromatography-isotopic dilution mass spectrometry method. Pharmacokinetic parameters (C(max), T(max), t(½) AUC(0-t), and AUC(0-∞) were calculated and analyzed statistically. The 2 formulations were considered bioequivalent if the 90% CIs of the log-transformed ratios (test/reference) of C(max) and AUC were within the predetermined bioequivalence ranges (70%-143% for C(max); 80%-125% for AUC), as established by the State Food and Drug Administration of China. Tolerability was determined by vital signs, clinical laboratory tests, 12-lead ECGs, physical examinations, and interviews with the subjects about adverse events (AEs).

RESULTS

A total of 24 healthy Chinese Han male volunteers were enrolled in and completed the study (mean [SD] age, 25.0 [2.4] years; height, 173.0 [5.6] cm; weight, 65.9 [6.4] kg; BMI, 22.0 [1.7] kg/m(2)). No formulation, period, or sequence effects were observed. The 90% CIs for the log-transformed C(max), AUC(0-t), and AUC(0-∞) were 89.7% to 103.8%, 86.7% to 101.7%, and 87.7% to 102.4%, respectively, which met the predetermined criteria for assuming bioequivalence. Two subjects (8.3%) experienced 2 mild AEs (increase in total bile acid and prolongation of the QT interval), which were not considered to be related to study drug administration.

CONCLUSIONS

This single-dose study of acetylcysteine 600 mg PO found that the 3 tablets of the generic test formulation and 1 tablet of the branded reference formulation met the regulatory criteria for assuming bioequivalence in these fasting healthy Chinese male volunteers. Both formulations were generally well tolerated.

The effects of paracetamol (acetaminophen) on hepatic tests in patients who chronically abuse alcohol - a randomized study

BACKGROUND

Retrospective accounts suggest that therapeutic doses of paracetamol can produce severe hepatic injury in patients with putative high-risk conditions, including alcoholism and infectious hepatitis. Metabolism of paracetamol to its hepatotoxic metabolite is enhanced in patients who abuse alcohol, who also have compromised liver defences from depressed hepatic glutathione.

AIM

To determine the effect of paracetamol on serum liver tests of newly abstinent subjects who abuse alcohol, including subjects with hepatitis C infection.

METHODS

A randomized, double-blind, placebo-controlled study. Adult alcohol abusers with a current drinking episode longer than 7 days received either placebo or paracetamol 4 g/day for 5 days.

RESULTS

Of 142 subjects enrolled, 74 received paracetamol and 68 received placebo. Mean ALT activity during treatment increased from 48 to 62 IU/L in the paracetamol group and from 47 to 49 IU/L in the placebo group. Maximum ALT was 238 and 249 IU/L in the paracetamol and control groups respectively. The INR remained unchanged and serum bilirubin decreased in both groups. Subgroup analyses for subjects with alcoholic hepatitis, hepatitis C virus antibody and other subgroups showed no statistical difference between groups.

CONCLUSION

Administration of paracetamol 4 g/day appears safe in newly abstinent patients who abuse alcohol.

A Population Study of the Frequency of High-Dose Acetaminophen Prescribing and Dispensing

Background:

Recurrent intake of 4 g/day or more of acetaminophen has been associated with elevation of serum alanine aminotransferase (ALT) levels in 30–40% of the exposed population and may result in hepatotoxicity.

Objective:

To describe the frequency that patients are prescribed acetaminophen doses that exceed 4 g/day across a large population.

Methods:

Using California's Medicaid (MediCal) fee-for-service population, pharmacy claims including over-the-counter (OTC) medications were examined for prescriptions that could result in acetaminophen doses of 4 g/day or more. The period studied, October 2004 through September 2005, was before the Part D pharmacy benefit was available to dually eligible Medicare patients when all prescriptions were covered by the MediCal claims process.

Results:

During the pre-Part D evaluation period, approximately 3.27 million beneficiaries were enrolled in the fee-for-service MediCal program. A total of 192,716 (5.9%) were potentially exposed to at least 1 day of 4 g/day or more of acetaminophen. Of those, 769 patients were potentially exposed to at least 1 day of 16 g/day or more. A total of 2664 beneficiaries were dispensed prescriptions and OTC products that, if taken as directed, would have resulted in more than 100 days of acetaminophen doses of 4 g/day or more during the study year.

Conclusions:

Despite electronic systems designed to warn dispensing pharmacists of duplications of drug class and cumulative excessive doses, potentially toxic amounts of acetaminophen are commonly prescribed and dispensed to this population. Better systems, increased awareness, and education of patients, prescribers, and pharmacists are needed to reduce this potential toxic exposure.

Gap junction dysfunction reduces acetaminophen hepatotoxicity with impact on apoptotic signaling and connexin 43 protein induction in rat

Acetaminophen (APAP) is a widely used antipyretic and analgesic agent. However, overdosing and sometimes even a recommended dose can lead to serious and conceivably fatal liver toxicity. Therefore, it is important to clarify understand mechanisms of hepatotoxicity induced by APAP. Gap junctions, formed by connexin, have important roles in maintenance of tissue homeostasis and control of cell growth and differentiation. In the liver, Cx32 is a major gap junction protein whose expression is known to gradually decrease with chronic liver disease progression. In the present study, acute hepatotoxic effects of APAP were found to be reduced in Cx32 dominant negative transgenic rats lacking normal gap junctional intercellular communication in the liver. In littermate wild-type rats, the injured centrilobular hepatocytes were positive for TUNEL staining and featured elevated expre ssion of cleaved caspase-3 and Cx43, which is not expressed in normal hepatocytes. These results suggest that APAP hepatotoxicity involves apoptosis, and induction of Cx43 expression may play an important role in the apoptotic signaling. Moreover, gap junctional functions of Cx32 can play important roles in removing damaged hepatocytes by apoptosis for liver tissue homeostasis.

Toxicodynamics of subacute co-exposure to groundwater contaminant arsenic and analgesic-antipyretic drug acetaminophen in rats

Arsenic is an environmental contaminant, while acetaminophen is an extensively used nonsteroidal analgesic-antipyretic drug. We evaluated whether subacute co-exposure to arsenic and acetaminophen would produce more toxicity than that caused by exposure to either of the xenobiotics in rats. Toxicity was evaluated through changes in body weight, feed consumption, liver weight and microsomal drug-metabolizing enzymes, lipid peroxidation and antioxidants in liver. Arsenic had no effect on body weight and feed consumption. Acetaminophen-mediated decrease in body weight was attenuated in the co-exposed rats. Acetaminophen alone or its co-administration with arsenic decreased feed consumption. Arsenic reduced acetaminophen-mediated increase in the activities of drug-metabolizing enzymes. The co-exposure caused lesser lipid peroxidation than the individual exposure. Arsenic or acetaminophen given alone depleted GSH and decreased the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase and these effects remained mostly unaffected after co-exposure. The results suggest that co-exposure to arsenic and acetaminophen may be less hazardous than their independent exposure in rats.

Intrinsic versus idiosyncratic drug-induced hepatotoxicity--two villains or one?

"Intrinsic" and "idiosyncratic" drug-induced liver injury reactions are commonly thought to arise by different modes of action. Intrinsic toxicity is reproducible in animals and occurs dose-dependently at sublethal doses. Environmental and genetic sensitivity factors can influence the toxicity of intrinsic hepatotoxicants. Among these is inflammatory stress. For example, exposure of mice to inflammatory bacterial lipopolysaccharide (LPS) causes a leftward shift in the dose-response relationship for acetaminophen hepatotoxicity; that is, acetaminophen toxicity is enhanced by LPS-induced inflammatory stress. Idiosyncratic reactions present themselves very differently than intrinsic ones; they happen in a minority of patients, with variable time of onset and no obvious relationship to drug dose, and they are not reproducible in usual animal tests. Although these characteristics seem to distinguish them from intrinsic reactions, consideration of fundamental principles of dose response can explain the differences. For a drug that causes idiosyncratic hepatotoxicity, the liver may not be a typical target for toxicity because the dose-response curve for hepatotoxicity lies to the right of the lethal dose. However, a sporadically occurring sensitivity factor, such as an inflammatory episode, could shift the dose-response curve for hepatotoxicity to the left, thereby bringing hepatotoxic doses into the therapeutic range. This hypothesis can account for the bizarre characteristics of idiosyncratic reactions and is supported by recent results showing that several drugs associated with human idiosyncratic reactions can be rendered hepatotoxic to rodents upon interaction with an inflammatory stimulus. In light of this view, intrinsic and idiosyncratic reactions may not be that different after all.

Severe hepatotoxic adverse reaction in a healthy schoolgirl after treatment with flucloxacillin

This is the first detailed description of a severe hepatotoxic reaction in a previously healthy 9-year-old schoolgirl after ingestion of some flucloxacillin tablets. She was clinically well within one week and alanine aminotransferase in serum was normalized in one month. Follow up for more than one year was normal.

Synthesis and pharmacological evaluation of N-phenyl-acetamide sulfonamides designed as novel non-hepatotoxic analgesic candidates

In this paper we report the design, synthesis and pharmacological evaluation of a series of N-phenyl-acetamide sulfonamide derivatives (5a-g), planned by structural modification on the prototype paracetamol (1). In this series (5a-g), compound LASSBio-1300 (5e; ID(50)=5.81 micromol/kg) stands out as a new non-hepatotoxic analgesic drug candidate. The increase of area, volume and electrostatic potential of paracetamol's analogues seems to be beneficial to the analgesic activity. Unlike paracetamol (1) and the other analogues (5a, 5d-g), compounds 5b and 5c presented an important anti-hypernociceptive activity associated to inflammatory pain.

Understanding the role of reactive metabolites in drug-induced hepatotoxicity: state of the science

Drug-induced liver injury (DILI) represents a major impediment to the development of new drugs and is a leading cause of drug withdrawal. The occurrence of hepatotoxicity has been closely associated with the formation of chemically reactive metabolites. Huge investment has focused on the screening of chemically reactive metabolites to offer a pragmatic approach to produce safer drugs and also reduce drug attrition and prevent market place withdrawal. However, questions surrounding the importance of chemically reactive metabolites still remain. Increasing evidence now exists for the multi-factorial nature of DILI, in particular the role played by the host immune system or disease state in the pathogenesis of DILI. This review aims to evaluate the current measures for the prediction and diagnosis of DILI and to highlight investigations being made to understand the multidimensional nature. Some of the steps being made to generate improved physiological systems to identify more sensitive, reflective mechanism-based biomarkers to aid the earlier identification of DILI and develop safer medicines are also discussed.

Acetaminophen hepatotoxicity

Acetaminophen is a commonly used antipyretic and analgesic agent. It is safe when taken at therapeutic doses; however, overdose can lead to serious and even fatal hepatotoxicity. The initial metabolic and biochemical events leading to toxicity have been well described, but the precise mechanism of cell injury and death is unknown. Prompt recognition of overdose, aggressive management, and administration of N-acetylcysteine can minimize hepatotoxicity and prevent liver failure and death. Liver transplantation can be lifesaving for those who develop acute liver failure.

Experimental study of hepatoprotective activity of hydroxymethyluracil

Hepatoprotective activity of pyrimidine derivative hydroxymethyluracil was studied on the model of acute paracetamol-induced liver damage in rats. Hydroxymethyluracil was shown to produce a strong hepatoprotective effect.