Drug-induced liver disease

Metabolic bioactivation of antidepressants: advance and underlying hepatotoxicity

Many drugs that serve as first-line medications for the treatment of depression are associated with severe side effects, including liver injury. Of the 34 antidepressants discussed in this review, four have been withdrawn from the market due to severe hepatotoxicity, and others carry boxed warnings for idiosyncratic liver toxicity. The clinical and economic implications of antidepressant-induced liver injury are substantial, but the underlying mechanisms remain elusive. Drug-induced liver injury may involve the host immune system, the parent drug, or its metabolites, and reactive drug metabolites are one of the most commonly referenced risk factors. Although the precise mechanism by which toxicity is induced may be difficult to determine, identifying reactive metabolites that cause toxicity can offer valuable insights for decreasing the bioactivation potential of candidates during the drug discovery process. A comprehensive understanding of drug metabolic pathways can mitigate adverse drug-drug interactions that may be caused by elevated formation of reactive metabolites. This review provides a comprehensive overview of the current state of knowledge on antidepressant bioactivation, the metabolizing enzymes responsible for the formation of reactive metabolites, and their potential implication in hepatotoxicity. This information can be a valuable resource for medicinal chemists, toxicologists, and clinicians engaged in the fields of antidepressant development, toxicity, and depression treatment.

ACR Appropriateness Criteria® Abnormal Liver Function Tests

Liver function tests are commonly obtained in symptomatic and asymptomatic patients. Various overlapping lab patterns can be seen due to derangement of hepatocytes and bile ducts function. Imaging tests are pursued to identify underlying etiology and guide management based on the lab results. Liver function tests may reveal mild, moderate, or severe hepatocellular predominance and can be seen in alcoholic and nonalcoholic liver disease, acute hepatitis, and acute liver injury due to other causes. Cholestatic pattern with elevated alkaline phosphatase with or without elevated γ-glutamyl transpeptidase can be seen with various causes of obstructive biliopathy. Acute or subacute cholestasis with conjugated or unconjugated hyperbilirubinemia can be seen due to prehepatic, intrahepatic, or posthepatic causes. We discuss the initial and complementary imaging modalities to be used in clinical scenarios presenting with abnormal liver function tests. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Triazole fungicides induce adipogenesis and repress osteoblastogenesis in zebrafish

Triazoles are a major group of azole fungicides commonly used in agriculture, and veterinary and human medicine. Maternal exposure to certain triazole antifungal medication causes congenital malformations, including skeletal malformations. We hypothesized that triazoles used as pesticides in agriculture also pose a risk of causing skeletal malformations in developing embryos. In this study, teratogenic effects of three commonly used triazoles, cyproconazole, paclobutrazol, and triadimenol, were investigated in zebrafish, Danio rerio. Exposure to the triazole fungicides caused bone and cartilage malformations in developing zebrafish larvae. Data from whole-embryo transcriptomics with cyproconazole suggested that exposure to this compound induces adipogenesis while repressing skeletal development. Confirming this finding, the expression of selected bone and cartilage marker genes were significantly downregulated with triazoles exposure as determined by quantitative PCR. The expression of selected adipogenic genes was upregulated by the triazoles. Furthermore, exposure to each of the three triazoles induced adipogenesis and lipid droplet formation in vitro in 3T3-L1 pre-adipocyte cells. In vivo in zebrafish larvae, cyproconazole exposure caused lipid accumulation. These results suggest that exposure to triazoles promotes adipogenesis at the expense of skeletal development, and thus they expand the chemical group of bona fide bone to fat switchers.

Incidence of Elevated Aminotransferases With or Without Bilirubin Elevation During Treatment With Immune Checkpoint Inhibitors: A Retrospective Study of Patients From Community Oncology Clinics in the United States

Introduction

The elevation of aminotransferase levels is regarded as an indicator of hepatocellular injury. The objective of this study was to describe real-world incidence of elevated aminotransferase levels with or without bilirubin elevation among patients treated with immune checkpoint inhibitors (ICIs) for solid tumors.

Methods

This retrospective cohort study used an electronic health record database representing > 1.5 million active United States (US) cancer patients and included patients diagnosed with any cancer between January 1, 2014 and March 31, 2019, and treated with one or more ICIs such as ipilimumab, tremelimumab, nivolumab, pembrolizumab, atezolizumab, durvalumab, and avelumab. The frequency, onset, duration, management of grade ≥ 3 elevation of aminotransferase levels with or without bilirubin elevation events, progression rate from isolated elevation of aminotransferase levels (IAT) to elevated aminotransferase levels with elevated bilirubin (ATWB), and mortality were described.

Results

Overall, 69,140 patients received 85,433 treatment courses. A total of 1,799 (2.11%) IAT and 441 (0.52%) ATWB events were observed during treatment courses. The median onset was 51 and 42 days for IAT and ATWB, respectively, across treatment courses, and the median duration of both was approximately seven days. Approximately 5% (n=96) of IAT events progressed to ATWB in a median time of 11 days. The proportion of patients who received corticosteroids after elevated aminotransferase levels with or without bilirubin was ~37% (n=671/1,799 of IAT and n=147/441 of ATWB) and ~8% discontinued ICI treatment (n=118/1,799 of IAT and n=43/441 of ATWB). About 46% (n=68/147) of ATWB and and 25% (n=172/671) of IAT events treated with steroids led to death within 45 days. Similarly, 49% (n=21/43) of ATWB and 35% (n=42/118) of IAT events leading to treatment discontinuation led to death within 45 days.

Conclusions

Real-world data from oncology clinics in US suggest low incidence of grade ≥ 3 elevated aminotransferase levels with or without bilirubin elevation following treatment with ICIs. In most cases, ICI treatment was not discontinued and management of elevated aminotransferases consisted of corticosteroid treatment in one-third of cases.

A Novel MicroRNA Signature for Cholestatic Drugs in Human Hepatocytes and Its Translation into Novel Circulating Biomarkers for Drug-Induced Liver Injury Patients

Drug-induced liver injury (DILI) diagnosis and classification (hepatocellular, cholestatic, and mixed) relies on traditional clinical biomarkers (eg ALT and ALP), despite limitations such as extrahepatic interferences, narrow dynamic ranges, and low mechanistic value. microRNAs may be very useful for complementing traditional DILI biomarkers but most studies in this direction have considered only paracetamol poisoning. Thus the value of microRNAs (miRNAs) as biomarkers for idiosyncratic DILI has not yet been demonstrated. In this study, we first examined the effect of model cholestatic drugs on the human hepatocyte miRNome by RNAseq and RT-qPCR. Results demonstrated that chlorpromazine, cyclosporin A, and ANIT induced (miR-21-3p, -21-5p, -22-3p, -27a-5p, -1260b, -34a-5p, and -98-5p) and repressed (-122-5p, -192-5p, -30c-5p, -424-5p, and -16-5p) specific miRNAs in sandwich-cultured upcyte hepatocytes. However, no common signature was found for cholestatic drugs. Next we investigated the levels of these miRNA in human serum and found that most were also significantly altered in cholestatic/mixed DILI patients upon hospital/ambulatory admission. However, miR-122-5p, -192-5p, -34a-5p, and -22-3p demonstrated a much more significant induction in patients with hepatocellular DILI, thus revealing better specificity for hepatocellular damage. Time-course analyses demonstrated that -1260b and -146 had a very similar profile to ALP, but with wider dynamic ranges, while -16-5p and -451a showed a negative correlation. Conversely, -122-5p and -192-5p correlated with ALT but with wider dynamic ranges and faster recoveries. Finally, the 122/451a and 122/16 ratios showed excellent prediction performances in both the study [area under the receiver operating characteristic curve (AUROC) >0.93] and the validation cohort (AUROC > 0.82), and can, therefore, be postulated for the first time as circulating miRNA biomarkers for idiosyncratic DILI.

The protective effect of Morin against ifosfamide-induced acute liver injury in rats associated with the inhibition of DNA damage and apoptosis

Morin is a flavonoid and broadly found in white berry and cranberry branch. Ifosfamide (IFOS) is known as an anticancer and cytotoxic drug especially on the liver. This study aimed to explore the potential protective effects of Morin against IFOS-induced liver toxicity in rats. The model group of rats received a single injection of IFOS (500 mg/kg; i.p.) at day 2, whereas the protective groups of rats were given two different doses of Morin (100 and 200 mg/kg; given by gavage) at days 1 and 2. All animals were then culled 24 h post-IFOS injection. We observed that IFOS caused liver injury, oxidative stress, inflammation, DNA damage, and apoptosis. However, Morin decreased the levels of aspartate aminotransferase (AST), alkaline phosphatase (ALP), alanine aminotransferase (ALT) (p < 0.05). While Morin contributed to the recovery of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione (GSH) levels, Morin decreased the levels of malondialdehyde (MDA) induced by IFOS in the liver (p < 0.05). Besides, the levels of nuclear factor kappa B (NF-κB), tumor necrosis factor-α (TNF-α), and P53 measured by ELISA test were reduced via Morin administration (p < 0.05). Lastly, the mRNA transcript levels of Bax, Apaf-1, Bcl-2, Bcl-xL, and inducible nitric oxide synthase (iNOS) determined by RT-PCR were down-regulated in the Morin groups (p < 0.05). These results indicate that Morin plays a protective role by reducing oxidative stress, inflammation, and apoptosis in the IFOS-induced liver injury in rats.

Mechanisms of Hepatic Cholestatic Drug Injury

Drug-induced cholestasis represents a form of drug-induced liver disease that can lead to severe impairment of liver function. Numerous drugs have been shown to cause cholestasis and consequently bile duct toxicity. However, there is still lack of therapeutic tools that can prevent progression to advanced stages of liver injury. This review focuses on the various pathological mechanisms by which drugs express their hepatotoxic effects, as well as consequences of increased bile acid and toxin accumulation in the hepatocytes.

Development of Autoimmune Hepatitis during Direct-acting Antiviral Therapy for Chronic Hepatitis C Virus Infection

An 81-year-old woman developed liver dysfunction after two months' treatment with direct-acting antivirals (DAAs) for chronic hepatitis C virus (HCV) infection. She was positive for serum anti-nuclear antibody, with an elevated immunoglobulin G level. A liver biopsy revealed high-grade interface hepatitis and infiltrate of lymphocytes and plasma cells. DAA-associated drug-induced autoimmune hepatitis (DI-AIH) was considered. Her liver dysfunction improved after discontinuing DAA therapy and starting prednisolone treatment. The differential diagnosis for AIH should include liver injury during DAA therapy for chronic HCV infection.

Nonacetaminophen Drug-Induced Acute Liver Failure

Acute liver failure of all causes is diagnosed in between 2000 and 2500 patients annually in the United States. Drug-induced acute liver failure is the leading cause of acute liver failure, accounting for more than 50% of cases. Nonacetaminophen drug injury represents 11% of all cases in the latest registry from the US Acute Liver Failure Study Group. Although rare, acute liver failure is clinically dramatic when it occurs, and requires a multidisciplinary approach to management. In contrast with acetaminophen-induced acute liver failure, non-acetaminophen-induced acute liver failure has a more ominous prognosis with a lower liver transplant-free survival.

Drug-induced liver injury: Do we know everything?

Interest in drug-induced liver injury (DILI) has dramatically increased over the past decade, and it has become a hot topic for clinicians, academics, pharmaceutical companies and regulatory bodies. By investigating the current state of the art, the latest scientific findings, controversies, and guidelines, this review will attempt to answer the question: Do we know everything? Since the first descriptions of hepatotoxicity over 70 years ago, more than 1000 drugs have been identified to date, however, much of our knowledge of diagnostic and pathophysiologic principles remains unchanged. Clinically ranging from asymptomatic transaminitis and acute or chronic hepatitis, to acute liver failure, DILI remains a leading causes of emergent liver transplant. The consumption of unregulated herbal and dietary supplements has introduced new challenges in epidemiological assessment and clinician management. As such, numerous registries have been created, including the United States Drug-Induced Liver Injury Network, to further our understanding of all aspects of DILI. The launch of LiverTox and other online hepatotoxicity resources has increased our awareness of DILI. In 2013, the first guidelines for the diagnosis and management of DILI, were offered by the Practice Parameters Committee of the American College of Gastroenterology, and along with the identification of risk factors and predictors of injury, novel mechanisms of injury, refined causality assessment tools, and targeted treatment options have come to define the current state of the art, however, gaps in our knowledge still undoubtedly remain.

Management of Hepatotoxicity Induced by the Use of Olanzapine

Numerous drugs cause hepatotoxicity clinically or biologically. Neuropsychiatric drugs constitute 16% of these drugs. The occurrence of hepatotoxicity induced by the use of olanzapine is expressed by the researchers. In such cases, generally the dose of olanzapine is reduced or the drug is completely discontinued and the treatment of the patient fails. The aim of this study is to report the case for whom elevated liver enzymes were observed but the process was managed without changing treatment dose and drug and to discuss this case with literature information. The present study has characteristics of being the first in the literature concerning management of the process.

Expression Levels of GABA-A Receptor Subunit Alpha 3, Gabra3 and Lipoprotein Lipase, Lpl Are Associated with the Susceptibility to Acetaminophen-Induced Hepatotoxicity

Drug-induced liver injury (DILI) is the serious and fatal drug-associated adverse effect, but its incidence is very low and individual variation in severity is substantial. Acetaminophen (APAP)-induced liver injury accounts for >50% of reported DILI cases but little is known for the cause of individual variations in the severity. Intrinsic genetic variation is considered a key element but the identity of the genes was not well-established. Here, pre-biopsy method and microarray technique was applied to uncover the key genes for APAP-induced liver injury in mice, and a cause and effect experiment employing quantitative real-time PCR was conducted to confirm the correlation between the uncovered genes and APAP-induced hepatotoxicity. We identified the innately and differentially expressed genes of mice susceptible to APAP-induced hepatotoxicity in the pre-biopsied liver tissue before APAP treatment through microarray analysis of the global gene expression profiles (Affymetrix GeneChip® Mouse Gene 1.0 ST for 28,853 genes). Expression of 16 genes including Gdap10, Lpl, Gabra3 and Ccrn4l were significantly different (t-test: FDR <10%) more than 1.5 fold in the susceptible animals than resistant. To confirm the association with the susceptibility to APAP-induced hepatotoxicity, another set of animals were measured for the expression level of selected 4 genes (higher two and lower two genes) in the liver pre-biopsy and their sensitivity to APAP-induced hepatotoxicity was evaluated by post hoc. Notably, the expressions of Gabra3 and Lpl were significantly correlated with the severity of liver injury (p<0.05) demonstrating that these genes may be linked to the susceptibility to APAP-induced hepatotoxicity.

Plasmapheresis for Refractory Pruritus due to Drug-Induced Cholestasis

Pruritus can be a distressing symptom seen in various cholestatic disorders. It is treated with medications like bile acid sequestrants. Drug-induced cholestasis usually resolves with withdrawal of the causative medication. We describe a case of refractory pruritus due to drug-induced cholestasis, not improved with withdrawal of the drug, managed effectively with multiple sessions of plasmapheresis.

A case of levocetirizine-induced liver injury

Levocetirizine is a second-generation nonsedative antihistaminic agent that has been demonstrated to be safe and effective for treating allergic disease. There was only one case report of levocetirizine-induced liver toxicity, but a liver biopsy was not performed. In this article, we present the first case of levocetirizine-induced liver injury with histologic findings. A 48-year-old man was hospitalized with jaundice and generalized pruritus that had developed after 2 months of therapy with levocetirizine for prurigo nodularis. Laboratory findings revealed acute hepatitis with cholestasis. A liver biopsy demonstrated portal inflammation and hepatitis with apoptotic hepatocytes. The patient fully recovered 3 weeks after withdrawing levocetirizine. Although levocetirizine is safe and effective, physicians should be aware of its potential hepatotoxicity.

Diagnostic Approach to the Patient with Jaundice following Trauma

Background and Aims:

Jaundice in trauma patients may reflect serious underlying pathology. The aim of this review was to determine the appropriate diagnostic approach to the patient with jaundice following trauma.

Methods:

A MEDLINE search was performed to retrieve publications which outlined the causes of jaundice in trauma patients.

Results:

The main causes of jaundice in trauma patients were found to be bilirubin overload caused by breakdown of transfused- and extravasated blood and hepatic dysfunction caused by sepsis, infections, initial shock and systemic hypotension. Bile duct injury or drug induced liver injury are rare. Liver function tests are often uninformative but commonly show a cholestatic pattern. Ultrasound, CT or ERCP are the diagnostic imaging methods most widely used. Abdominal ultrasound and CT may reveal specific organ injuries, bile duct dilatation, intraabdominal fluid collections, hematomas or acalculus cholecystitis. ERCP is often diagnostic and permits a therapeutic intervention when a bile duct injury is present.

Conclusions:

The primary aim of the diagnostic approach should be to identify all cases of bile duct injury or obstruction. Sepsis and infections should be actively looked for. The number of blood transfusions must be calculated. Ultrasound, CT or ERCP are the diagnostic imaging methods most widely used.

Drug-induced hepatotoxicity in cancer patients - implication for treatment

INTRODUCTION

All anticancer drugs can cause idiosyncratic liver injury. Therefore, hepatoprotective agents assume particular importance to preserve liver function. Hepatic injury represents 10% of cases of acute hepatitis in adults; drug-related damage is still misjudged because of relative clinical underestimation and difficult differential diagnosis. Chemotherapeutic agents can produce liver toxicity through different pathways, resulting in different categories of liver injuries, but these drugs are not homogeneously hepatotoxic. Frequently, anticancer-induced hepatotoxicity is idiosyncratic and influenced by multiple factors.

AREAS COVERED

The aim of this paper is to perform a review of the literature regarding anticancer-induced liver toxicity. We described hepatotoxicity mechanisms of principal anticancer agents and respective dose reductions. Furthermore, we reviewed studies on hepatoprotectors and their optimal use. Tiopronin, magnesium isoglycyrrhizinate and S-Adenosylmethionine (AdoMet) demonstrated, in some small studies, a potential hepatoprotective activity.

EXPERT OPINION

Actually, in the literature only small experiences are reported. Even though hepatoprotective agents seem to be useful in the oncologic setting, the lack of well-designed prospective Phase III randomized controlled trials is a major limit in the introduction of hepatoprotectors in cancer patients and these kind of studies are warranted to support their use and to give further recommendations for the clinical practice.

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.

The Art and Science of Diagnosing and Managing Drug-induced Liver Injury in 2015 and Beyond

Drug-induced liver injury (DILI) remains a leading reason why new compounds are dropped from further study or are the subject of product warnings and regulatory actions. Hy's Law of drug-induced hepatocellular jaundice causing a case-fatality rate or need for transplant of 10% or higher has been validated in several large national registries, including the ongoing, prospective U.S. Drug-Induced Liver Injury Network. It serves as the basis for stopping rules in clinical trials and in clinical practice. Because DILI can mimic all known causes of acute and chronic liver disease, establishing causality can be difficult. Histopathologic findings are often nonspecific and rarely, if ever, considered pathognomonic. A daily drug dose >50-100 mg is more likely to be hepatotoxic than does <10 mg, especially if the compound is highly lipophilic or undergoes extensive hepatic metabolism. The quest for a predictive biomarker to replace alanine aminotransferase is ongoing. Markers of necrosis and apoptosis such as microRNA-122 and keratin 18 may prove useful in identifying patients at risk for severe injury when they initially present with a suspected acetaminophen overdose. Although a number of drugs causing idiosyncratic DILI have HLA associations that may allow for pre-prescription testing to prevent hepatotoxicity, the cost and relatively low frequency of injury among affected patients limit the current usefulness of such genome-wide association studies. Alanine aminotransferase monitoring is often recommended but has rarely been shown to be an effective method to prevent serious DILI. Guidelines on the diagnosis and management of DILI have recently been published, although specific therapies remain limited. The LiverTox Web site has been introduced as an interactive online virtual textbook that makes the latest information on more than 650 agents available to clinicians, regulators, and drug developers alike.

Drug Induced Liver Injury: Review with a Focus on Genetic Factors, Tissue Diagnosis, and Treatment Options

Drug-induced liver injury (DILI) is a rare but potentially life threatening adverse drug reaction. DILI may mimic any morphologic characteristic of acute or chronic liver disease, and the histopathologic features of DILI may be indistinguishable from those of other causes of liver injury, such as acute viral hepatitis. In this review article, we provide an update on causative agents, clinical features, pathogenesis, diagnosis modalities, and outcomes of DILI. In addition, we review results of recently reported genetic studies and updates on pharmacological and invasive treatments.

Value of preapproval safety data in predicting postapproval hepatic safety and assessing the legitimacy of class warning

OBJECTIVE

The objective of this study was to systematically evaluate whether preapproval safety data for nonhepatotoxic drugs and hepatotoxic drugs can be compared to improve preapproval prediction of postapproval hepatic safety and to assess the legitimacy of applying class warnings.

METHODS

Drugs within a therapeutic class that included at least one drug that had been withdrawn from the market because of liver toxicity or had a warning of potential liver toxicity issued by major regulatory agencies, and at least one drug free from such regulatory action, were identified and divided into two groups: drugs with and drugs without regulatory action. Preapproval clinical data [including the elevation rates of alanine aminotransferse (ALT) and withdrawal due to liver toxicity, the number of patients with combined elevation of ALT and bilirubin, and liver failure] and nonclinical data (including chemical structures, metabolic pathways, and other significant findings in animal studies) were compared between the two groups.

RESULTS

Six drug classes were assessed in this study: thiazolidinediones, cyclooxygenase-2 inhibitors, fluoroquinolones, catechol-O-methyltransferase (COMT) inhibitors, leukotriene receptor inhibitors, and endothelin receptor antagonists. In two classes (COMT inhibitors and endothelin receptor antagonists), drugs with regulatory action had significantly higher rates of ALT elevation of more than threefold and greater numbers of patients with combined elevation of ALT and bilirubin than drugs without regulatory action. Drugs with regulatory action also had chemical structures or metabolic pathways associated with the toxicity. The legitimacy of class warnings was refuted in all six classes of drugs.

CONCLUSION

Preapproval safety data may help predict postapproval hepatic safety and can be used to assess the legitimacy of applying class warnings.

Two azole fungicides (carcinogenic triadimefon and non-carcinogenic myclobutanil) exhibit different hepatic cytochrome P450 activities in medaka fish

Conazoles are a class of imidazole- or triazole-containing drugs commonly used as fungicides in agriculture and medicine. The broad application of azole drugs has led to the contamination of surface aquifers receiving the effluent of municipal or hospital wastewater or agricultural runoff. Several triazoles are rodent carcinogens; azole pollution is a concern to environmental safety and human health. However, the carcinogenic mechanisms associated with cytochrome P450 enzymes (CYPs) of conazoles remain unclear. We exposed adult medaka fish (Oryzias latipes) to continuous aqueous solutions of carcinogenic triadimefon and non-carcinogenic myclobutanil for 7 to 20 days at sub-lethal or environmentally relevant concentrations and assessed hepatic CYP activity and gene expression associated with CYP-mediated toxicity. Both triadimefon and myclobutanil induced hepatic CYP3A activity, but only triadimefon enhanced CYP1A activity. The gene expression of cyp3a38, cyp3a40, pregnane x receptor (pxr), cyp26b, retinoid acid receptor γ1 (rarγ1) and p53 was higher with triadimefon than myclobutanil. As well, yeast-based reporter gene assay revealed that 4 tested conazoles were weak agonists of aryl hydrocarbon receptor (AhR). We reveal differential CYP gene expression with carcinogenic and non-carcinogenic conazoles in a lower vertebrate, medaka fish. Liver CYP-enzyme induction may be a key event in conazole-induced tumorigenesis. This information is essential to evaluate the potential threat of conazoles to human health and fish populations in the aquatic environment.

Nonprescription pain medication use in collegiate athletes: a comparison of samples

BACKGROUND

Despite recent research, nonprescription pain medication use among collegiate athletes across all divisions of the National Collegiate Athletic Association (NCAA) is still not well understood.

HYPOTHESIS

Non-Division I-A NCAA athletes have a different usage pattern of nonprescription pain medication than NCAA Division I-A football athletes.

METHODS

A modified version of a nonprescription medication usage survey that had been used with Division I-A football athletes was distributed to Division II and Division III athletes during pre-participation exams. The statistics were analyzed by calculating the z-ratio for the significance of the difference between 2 independent proportions.

RESULTS

A total of 198 athletes from 16 different sports were surveyed. It was found that 62% of athletes used nonprescription medications for sports-related pain, which was significantly lower than previous findings for Division I-A football athletes: 12% reported taking more than the recommended dose; 1.5% reported taking nonprescription pain medication for > 10 consecutive days; and 38% reported that they read the label the first time they took a new nonprescription pain medication. These results, when compared with findings on Division I-A football athletes, demonstrated that Division II and III athletes are less likely to take more than the recommended dose of nonprescription pain medications and are less likely to use the medications for > 10 consecutive days-characteristics that are used to define misuse. Similar results were found when comparing Division I-A football athletes with non-Division I-A football athletes.

CONCLUSIONS

Athletes from NCAA Division II and Division III sports appear to use nonprescription pain medication for sports-related pain less often and have lower rates of misuse than do Division I-A football athletes. Division I-A football athletes may be more likely to misuse nonprescription pain medication than non-Division I-A athletes. Special attention should be paid to this population to help reduce adverse event risks.

Chemotherapy-induced hepatotoxicity

Most hepatotoxicity secondary to chemotherapy is idiosyncratic and, therefore, neither dose dependent nor predictable. Some chemotherapy is cleared by the liver and requires dose adjustment in the face of significant liver dysfunction. In addition, preexisting abnormal liver function has been shown to increase the risk of hepatotoxicity. In addition to typical hepatocellular injury, other presentations, including cholestasis and hepatic sinusoidal obstruction syndrome, also commonly occur. The outcomes can range from asymptomatic liver function test abnormalities, which resolve spontaneously, to cirrhosis, which occurs despite discontinuation of the chemotherapeutic agent.

An updated review on drug-induced cholestasis: mechanisms and investigation of physicochemical properties and pharmacokinetic parameters

Drug-induced cholestasis is an important form of acquired liver disease and is associated with significant morbidity and mortality. Bile acids are key signaling molecules, but they can exert toxic responses when they accumulate in hepatocytes. This review focuses on the physiological mechanisms of drug-induced cholestasis associated with altered bile acid homeostasis due to direct (e.g., bile acid transporter inhibition) or indirect (e.g., activation of nuclear receptors, altered function/expression of bile acid transporters) processes. Mechanistic information about the effects of a drug on bile acid homeostasis is important when evaluating the cholestatic potential of a compound, but experimental data often are not available. The relationship between physicochemical properties, pharmacokinetic parameters, and inhibition of the bile salt export pump among 77 cholestatic drugs with different pathophysiological mechanisms of cholestasis (i.e., impaired formation of bile vs. physical obstruction of bile flow) was investigated. The utility of in silico models to obtain mechanistic information about the impact of compounds on bile acid homeostasis to aid in predicting the cholestatic potential of drugs is highlighted.

Drug-induced liver injury in the elderly

Historically, the elderly have been considered to be at increased risk for drug-induced liver injury (DILI). Animal studies have demonstrated changes in hepatic physiology that affect drug metabolism in the aging liver; however, there is no evidence that this leads to any appreciable deterioration of liver function in healthy older humans. Updated data from international DILI registries give us pause to consider whether the elderly are truly at increased risk to develop hepatic injury. Instead, hepatotoxicity in the elderly appears to be more a function of drug exposure, polypharmacy and drug-drug interactions. Isoniazid and benoxaprofen are the only two agents with a well-studied correlation between increasing age and risk of DILI. Nevertheless, given the increasing proportion of patients over age 65 in the U.S. and abroad, the influence of age on the risk of DILI is the focus of this review.

Drug-induced hepatotoxicity in a tertiary care hospital in rural South India

BACKGROUND

Liver is the main organ for metabolism of drugs and hepatotoxicity is a potential adverse effect for most drugs.

AIMS

This study was to study the frequency of drug-induced hepatotoxicity and to find the common drugs causing hepatotoxicity.

MATERIALS AND METHODS

The study was conducted at a tertiary care hospital in rural India. It is a study based on case series analysis. All patients with an abnormal liver function report, between July 2006 and July 2007, were included in the study

RESULTS

The study included 411 patients. Among them 141 patients were females and 270 males. The common cause for abnormal liver function was alcoholic liver disease (30.4%) followed by drug-induced hepatotoxicity (15.8%) and malaria (15.3%). Drug-induced hepatotoxicity was seen in 65 patients. It was common in males (55%) compared to females (44%). The mean age of the patients with drug-induced hepatotoxicity was 43±15.9. Antitubercular drugs were the commonly encountered drugs (44%) causing hepatotoxicity followed by lipid lowering agents (41%). The others drugs included antiretroviral drugs (6%),steroids (5%) and chlorpromazine (2%).

CONCLUSION

A thorough history of drug intake must be taken in all patients presenting with abnormal hepatic function.

Protective Effect of Ethanol Extract of Gymnosporia montana (Roth) Bemth. in Paracetamol-induced Hepatotoxicity in Rats

The aim of the present study was to explore the hepatoprotective activity of the ethanol extract of leaves of Gymnosporia montana (Roth) Bemth. (Family: Celastraceous) against paracetamol-induced hepatotoxicity. Hepatotoxicity in Wistar rats was induced by a single intraperitoneal dose of 500 mg/kg of paracetamol and studied by comparing parameters such as serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, alkaline phosphatase and histopathological examination of liver. Pre and post-treatment with ethanol extract of Gymnosporia montana (Roth) Bemth. at doses of 50 and 100 mg/kg was studied by comparing the above mentioned parameters with silymarin (100 mg/kg) as standard. Both doses of ethanol extract of Gymnosporia montana (Roth) Bemth. were found to be hepatoprotective. Extract at the dose of 100 mg/kg produced effects comparable to those of silymarin. The present study indicates that alcohol extract of Gymnosporia montana (Roth) Bemth. possessed significant hepatoprotective activity.

Drug-induced cholestasis

Recent progress in understanding the molecular mechanisms of bile formation and cholestasis have led to new insights into the pathogenesis of drug-induced cholestasis. This review summarizes their variable clinical presentations, examines the role of transport proteins in hepatic drug clearance and toxicity, and addresses the increasing importance of genetic determinants, as well as practical aspects of diagnosis and management.

Predicting and preventing acute drug-induced liver injury: what's new in 2010?

IMPORTANCE OF THE FIELD

The field of drug-induced liver injury (DILI) continues to expand in terms of global registries and with new agents added every year. Given the need to improve on our current methods of preclinical testing and monitoring for DILI during both clinical trials and in the post-approval setting, there is increasing research aimed at better understanding why injury occurs and who is most susceptible. To this end, the active pursuit of biomarkers that will predict injury prior to its occurrence and genetic testing that can identify individuals at risk of DILI continue to be at the forefront.

AREAS COVERED IN THIS REVIEW

While alanine aminotransferase (ALT) testing remains the workhorse of biochemical monitoring, it only detects hepatic injury after it has occurred and, therefore, is not a true predictor. The utility and shortcomings of ALT and other liver tests are reviewed along with a synopsis of several other candidate biomarkers that are being studied. In addition, we review the recent data supporting testing for genetic predisposition to DILI and how identifying clinical risk factors may translate into better means for preventing DILI.

WHAT THE READER WILL GAIN

We update the basis on which age and gender are considered risk factors for DILI, and review the latest reports detailing the association of several candidate genes and the development of DILI in a susceptible patient. Human leukocyte antigen-B*5701 is closely linked to the hypersensitivity reaction seen with abacavir, and such screening has been successfully incorporated into HIV treatment around the globe and offers the promise that testing for other genetic markers will soon become a routine part of clinical practice. At present, candidate genes conferring specific susceptibility to DILI have been identified for a relatively few agents (e.g., flucloxacillin, amoxicillin-clavulanate, ximelagatran and isoniazid), but many more are under study. Preventing DILI often comes down to avoiding the use of potentially hepatotoxic drugs in certain situations, and we review the clinical scenarios in which this is most relevant.

TAKE HOME MESSAGE

Given the number and range of studies aimed at identifying predictors of DILI, the focus of this review is to summarize what we consider to be the most relevant new information published on the topics of clinical and genetic factors that predispose to DILI, the use of biomarkers as predictors of acute DILI, along with advances in prevention strategies.

Prescribing medications in patients with decompensated liver cirrhosis

Patients with decompensated liver cirrhosis have various serious complications which require multiple drugs for therapeutic or prophylactic use. Majority of the drugs are primarily metabolized and excreted by hepatobiliary system; hence, liver cell necrosis contributes to impaired drug handling in liver failure while portosystemic shunt can alter drug action in cirrhosis. Hence, in order to decide drug dosing in liver failure, 3 important factors need to be considered (1) pharmacokinetic alterations of drugs, (2) pharmacodynamic alteration of drugs, and (3) increased susceptibility of patients to adverse events particularly hepatotoxicity. Though there is no predictable test which can be used to determine drug dosage in patients with decompensated liver cirrhosis, drugs with first pass metabolism require reduction in oral dosages, for high clearance drugs both loading and maintenance dosages need adjustment, for low clearance drugs maintenance dose needs adjustment, whenever possible measuring drug level in the blood and monitoring of adverse events frequently should be done. No evidence-based guidelines exist for the use of medication in patients' with liver cirrhosis. There are hardly any prospective studies on the safety of drugs in cirrhotic patients. According to the experts opinion, most of the drugs can be used safely in patients with cirrhosis, but drug-induced hepatotoxicity may be poorly tolerated by patients with cirrhosis; hence, potential hepatotoxins should be avoided in patients with liver cirrhosis. Potentially hepatotoxic drugs may be used in patients with liver cirrhosis based on the clinical needs and when there are no alternatives available. Caveat for the prescribing medications in patients with cirrhosis the drug dosing should be individualized depending on a number of factors like nutritional status, renal function, adherence, and drug interaction. Monitoring of the liver function at frequent intervals is highly recommended.

Drug-Induced Liver Disease and Drug Use Considerations in Liver Disease

Chronic liver disease encompasses a large number of hepatic disorders. One of the most important etiologies of liver disease is drug-induced liver disease, which is the leading cause of liver failure in patients referred for liver transplantation in the United States. Drug-induced liver disease can present in all forms of acute and chronic liver disease with highly variable clinical presentations. There is no effective treatment for most drug-induced liver disease and the recognition and prevention of drug-induced liver disease remain the most important management strategy. Drug dosing in patients with liver disease represents an even more challenging task to clinicians, as there is only scant information on biomarkers that can be used to predict the pharmacokinetic changes of drugs in patients with underlying liver disease. Several factors contribute to alterations in drugs metabolism and clearance in cirrhotic patients, including the severity of the liver disease and the metabolic pathways of each individual drug. Only general guidelines on dosage adjustment in patients with hepatic impairment are available. When drugs with extensive hepatic metabolism are required in patients with preexisting liver disease, benefit of therapeutic effect must be evaluated against the risk of toxicity, and the drugs must be initiated with extreme caution with appropriate dosage reduction.

Review article: The use of potentially hepatotoxic drugs in patients with liver disease

BACKGROUND

Misconceptions surround the use of hepatotoxic drugs in chronic liver disease. While many prescription and over-the-counter (OTC) agents can be used safely, this often runs counter to labelled warnings/contraindications, especially for the statins and other commonly used agents.

AIM

To evaluate published data on the use of hepatotoxic drugs in chronic liver disease including pharmacokinetic changes in cirrhosis and drug interactions, where available, to formulate recommendations on their use.

METHODS

Using a combination of PubMed searches, review texts, the Physicians' Desk Reference and expert opinion, drugs considered at higher risk of hepatotoxicity in chronic liver disease were evaluated.

RESULTS

Most drugs and OTC products including herbals have not been formally studied in chronic liver disease, but available data suggest that several of the most commonly used agents, especially the statins, can be used safely. While there is an increased risk of drug-induced liver injury for drugs used in the treatment of tuberculosis and HIV patients with hepatitis B or C, recommendations for their safe use are emerging.

CONCLUSIONS

Although many clinicians remain hesitant to use hepatotoxic drugs in chronic liver disease, the database supporting this view is limited to just a few agents. Most medications can be used safely in patients with chronic liver disease with appropriate monitoring.

Risperidone and liver function tests in children and adolescents: a short-term prospective study

OBJECTIVE

Revealing of unknown adverse effects of atypical antipsychotics on pediatric population may take a long period of time. The purpose of this prospective study is to document changes in the liver function tests (LFTs) associated with risperidone usage in a group of children and adolescents.

METHOD

Study subjects consist of 120 youths with ages ranging from 3-17 years. For this study, patients' baseline and follow-up weight and hepatobiliary function tests including alanine aminotransferases(ALT) and aspartat aminotransferases (AST), gamma gluatamyl transerase (GGT), alkaline phosphatase (ALP) and serum bilirubin levels were measured before and after the treatment period of one month.

RESULTS

Only one male patient's ALT levels increased up to three-fold and AST levels increased up to two-fold of the basal levels. First month mean levels of liver enzymes and billuribin of the patients were significantly higher than the baseline. Sixty-three patients (52.5%) showed an asymptomatic increase in the liver enzymes and/or billuribin levels of the first month of this study. Weight gain was observed in 58 patients (57.4%). There was no significant association between changes in weight and liver enzymes and billuribin levels.

CONCLUSION

We found clinically non significant liver function test abnormalities mostly in the form of ALP elevation in 52.5% and marked liver enzymes elevation in 0.8% of risperidone-treated subjects. However use of concomitant medications and variations in age are the limitations of this study. These findings suggest that risperidone treatment in the short term may lead to liver function changes in children and adolescents.

The role of hepatitis E virus testing in drug-induced liver injury

BACKGROUND

Locally acquired hepatitis E is an emerging infection in developed countries and can be misdiagnosed as drug-induced liver injury.

AIM

To study the role of hepatitis E virus (HEV) testing in drug-induced liver injury.

METHODS

Retrospective review of a cohort of patients with suspected drug-induced liver injury (n = 69) and hepatitis E (n = 45). The standard criteria for drug-induced liver injury were applied. Patients with suspected drug-induced liver injury who met these criteria were retrospectively tested for HEV on stored sera taken at the time of presentation. The two cohorts were compared to determine variables that predicted either of the diagnoses.

RESULTS

Forty-seven out of 69 patients had criterion-referenced drug-induced liver injury. 22/47 were HEV negative and thus had confirmed drug-induced liver injury. 19/47 were not tested for HEV, as there was no sera available from the time of presentation. 6/47 were HEV positive and thus did not have drug-induced liver injury, but had hepatitis E infection. Compared to patients with confirmed drug-induced liver injury, patients with hepatitis E were significantly more likely to be male (OR 3.09, CI 1.05-9.08); less likely to present in November and December (0.03, CI 0.01-0.52); have lower serum bilirubin (P = 0.015); and higher serum alanine aminotransferase (P < 0.001) and alanine aminotransferase/alkaline phosphatase ratio (P < 0.001).

CONCLUSION

The diagnosis of drug-induced liver injury is not secure without testing for HEV.

Efficacy and safety of high-dose pravastatin in hypercholesterolemic patients with well-compensated chronic liver disease: Results of a prospective, randomized, double-blind, placebo-controlled, multicenter trial

The hepatotoxic potential of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors in patients with underlying chronic liver disease remains controversial. We performed a multicenter, randomized, double-blind, placebo-controlled, parallel-group trial that compared pravastatin (80 mg) to a placebo administered once daily to hypercholesterolemic subjects greater than 18 years of age with at least a 6-month history of compensated chronic liver disease and with a low-density lipoprotein cholesterol (LDL-C) level greater than or equal to 100 mg/dL and a triglyceride (TG) level lower than 400 mg/dL. The efficacy was determined by the percentage change in LDL-C [along with the total cholesterol (TC), high-density lipoprotein cholesterol, and TG] from the baseline to week 12. The safety was analyzed by the proportion of subjects who developed at least 1 alanine aminotransferase (ALT) value greater than or equal to 2 times the upper limit of normal for those with normal ALT at the baseline or a doubling of the baseline ALT for those with elevated ALT at the baseline during 36 weeks of treatment. A total of 630 subjects were screened, and 326 subjects were randomized; nonalcoholic fatty liver disease was present in 64%, and chronic hepatitis C was present in 23%. In the intent-to-treat population, pravastatin (80 mg/day) significantly lowered the mean LDL-C, TC, and TG values at week 12 and at other times (weeks 4, 8, 24, and 36) in comparison with the placebo. The incidence of subjects who met the primary prespecified ALT event definition was lower in the pravastatin group at all times over the 36 weeks of therapy in comparison with the placebo group, although the difference was not statistically significant. No differences were seen on the basis of the baseline ALT values or among the different liver disease groups.

CONCLUSION

High-dose pravastatin (80 mg/day) administered to hypercholesterolemic subjects with chronic liver disease significantly lowered LDL-C, TC, and TGs in comparison with the placebo and was safe and well tolerated. The concern over an increased potential for statin-induced hepatotoxicity in patients with chronic liver disease appears to be lessened on the basis of these results.

Case report: mixed cholestatic/hepatocellular liver injury induced by the herbicide quizalofop-p-ethyl

CONTEXT

Quizalofop-p-ethyl is an often applied, slightly toxic herbicide for which no severe toxicity has been reported in humans.

CASE PRESENTATION

We present the case of a farmer exposed to quizalofop-p-ethyl who presented with obstructive cholestasis. A complete workup disclosed no other cause of liver pathology, but liver biopsy established drug-induced hepatotoxicity. The patient was treated with ursodeoxycholic acid and prednisolone, and was recovered fully 70 days after his exposure to the herbicide. The patient was followed for the next 9 months.

CONCLUSION

Quizalofop-p-ethyl can induce a mixed cholestatic/hepatocellular liver injury. We discuss possible mechanisms implicated in liver injury after exposure to quizalofop-p-ethyl.

RELEVANCE TO CLINICAL OR PROFESSIONAL PRACTICE

In patients presenting with mixed cholestatic/ hepatocellular liver injury, occupational exposure to quizalofop-p-ethyl in the course of agricultural use should be investigated.

A review of liver function tests during treatment with atypical antipsychotic drugs: a chart review study

OBJECTIVE

Atypical antipsychotic drugs commonly cause asymptomatic increase in the liver enzymes and serum bilirubin levels. However they rarely may induce a serious hepatic toxicity. In this article we aimed to evaluate the effect of atypical antipsychotic drugs namely olanzapine, risperidone and quetiapine on the hepatic enzymes and serum bilirubin levels in psychiatric patients.

METHOD

Chart reviews of 312 patient followed-up at Psychiatry Department of Zonguldak Karaelmas University Hospital were examined in detail. The patients whose baseline and follow-up liver function tests including alanine aminotransfeaminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), alkaline phosphotase (ALP) and serum bilirubin that were measured before and within the treatment period of first and sixth months were enrolled. Forty eight males and 62 females whose ages ranging from 12 to 65 years were eligible for this study (no pregnant case was present).

RESULTS

The repartition according to treatment is as follows: olanzapine (n=33), risperidone (n=29), and quetiapine (n=48). Two of the 110 patients (1.8%) presented with increased AST levels of up to 4 fold and ALT of thrice the basal level and needed to stop treatment (AST increase in one female with olanzapine 20 mg/day; ALT increase in one male with olanzapine 30 mg/day). Thirty of the 110 patients (27.2%) showed asymptomatic increases in ALT, AST, GGT and serum bilirubin levels in the first month of the study. After 6 months of the treatment, abnormalities in the liver function tests were observed in 25 patients (22.7%).

CONCLUSION

These results were in accordance with previous studies that asymptomatic increase of liver enzymes are common but significant liver enzyme elevations are rare during atypical antipsychotic treatment. We suggest that obtaining baseline liver enzyme tests before atypical antipsychotic therapy and monitoring regularly specifically in patients with risk factors for liver damage during therapy.

Causality assessment of drug-induced hepatotoxicity: promises and pitfalls

Drug-induced liver injury is the leading cause of acute liver failure in the United States, but the ability to ascribe hepatic injury confidently to a specific drug remains a challenging and often difficult pursuit. This article explores the ongoing challenges inherent in what is currently a clinical process of elimination made in the attempt of assigning causality in drug-induced liver injury. In particular, it points out the shortcomings and pitfalls that often limit the applicability of the causality-assessment methodologies currently in use.

Antibiotic therapy: a major cause of drug-induced jaundice in southwest England

OBJECTIVE

To determine the incidence and causes of drug-induced jaundice in a rural community.

METHODS

A retrospective analysis of 800 patients presenting to a single-centre jaundice referral system serving a community of 400 000 over a period of 66 months (1998-2004). Standard criteria for drug-induced liver injury were applied to patients with a putative diagnosis of drug-induced jaundice. The incidence rates per prescription of drug-induced jaundice caused by co-amoxiclav and flucloxacillin were derived from local and national annual prescription rates.

RESULTS

The incidence of drug-induced jaundice was 1.27 (confidence limits 0.85-1.8) per 100 000 per annum in a total of 28 patients (17 men, mean age 69 years). Antibiotics were the commonest cause of jaundice (n=21). Of these, co-amoxiclav (n=9) and flucloxacillin (n=7) caused the majority with an incidence rate per 100 000 prescriptions of 9.91 (4.6-18.0) and 3.60 (1.5-7.2), respectively. Co-amoxiclav-induced jaundice was observed more commonly in elderly males (age 65 years, M : F 7 : 2). In those patients with flucloxacillin or co-amoxiclav-induced jaundice, bilirubin ranged from 54 to 599 mumol/l (267 mumol/l) with a resolution of jaundice between 30 and 90 days. Counselling with regard to potential drug-induced liver injury and reporting of the adverse reaction had been performed in 1/28 patients.

CONCLUSIONS

8.1% patients with no biliary obstruction and jaundice had a drug-induced and predominantly antibiotic-related aetiology particularly affecting an elderly population. We recommend that all patients receiving co-amoxiclav and flucloxacillin should be counselled before the therapy regarding the potential risk of jaundice and that an alternative antibiotic to co-amoxiclav is used if possible in men over the age of 60 years.

Severe liver enzyme elevations after three years of olanzapine treatment: a case report and review of olanzapine associated hepatotoxicity

Atypical antipsychotics commonly cause isolated asymptomatic increase in the aminotransferase levels. Among these atypical antipsychotics, mostly transient, asymptomatic increase in hepatic enzymes has been reported with olanzapine, however olanzapine rarely may induce a clinical and/or biological hepatic toxicity. The pathogenesis of olanzapine-associated hepatotoxicity is not well known and is mostly a transient phenomenon. However, substantial and lasting changes may occur and result in symptomatic hepatitis. In the following case report, we report on a 44-year-old female patient diagnosed as Bipolar Disorder Type I, whose liver enzyme levels increased ten fold of normal ranges during the third year of the olanzapine treatment and returned to the normal levels within three weeks after olanzapine discontinuation. Although significant liver enzyme elevations are uncommon during olanzapine treatment, based on reports of serious hepatotoxicity, controlled and longitudinal research are needed to learn side effects of this drug on liver. Clinicians should be aware of possible hepatotoxic effects of atypical antipsychotics and should monitor the liver enzyme levels whenever they feel necessary.