Relationship between daily dose of oral medications and idiosyncratic drug-induced liver injury: search for signals

Diagnosis and Management of Drug-Induced Liver Injury (DILI) in Patients with Pre-Existing Liver Disease

The relationship between drugs and pre-existing liver disease is complex, particularly when increased liver tests (LTs) or new symptoms emerge in patients with pre-existing liver disease during drug therapy. This requires two strategies to assess whether these changes are due to drug-induced liver injury (DILI) as a new event or due to flares of the underlying liver disease. Lacking a valid diagnostic biomarker, DILI is a diagnosis of exclusion and requires causality assessment by RUCAM, the Roussel Uclaf Causality Assessment Method, to establish an individual causality grading of the suspected drug(s). Flares of pre-existing liver disease can reliably be assessed in some hepatotropic virus infections by polymerase chain reaction (PCR) and antibody titers at the beginning and in the clinical course to ascertain flares during the natural course of the disease. Unfortunately, flares cannot be verified in many other liver diseases such as alcoholic liver disease, since specific tests are unavailable. However, such a diagnostic approach using RUCAM applied to suspected DILI cases includes clinical and biological markers of pre-existing liver diseases and would determine whether drugs or underlying liver diseases caused the LT abnormalities or the new symptoms. More importantly, a clear diagnosis is essential to ensure effective disease management by drug cessation or specific treatment of the flare up due to the underlying disease.

The transformation in biomarker detection and management of drug-induced liver injury

Drug-induced liver injury (DILI) is a major concern for patients, care givers and the pharmaceutical industry. Interpretation of the serum biomarkers routinely used to detect and monitor DILI, which have not changed in almost 50 years, can be improved with recently proposed models employing quantitative systems pharmacology. In addition, several newer serum biomarkers are showing great promise. Studies in rodents indicate that the ratio of the caspase cleaved fragment of cytokeratin 18 to total K18 in serum (termed the "apoptotic index") estimates the relative proportions of apoptosis vs necrosis during drug-induced liver injury. Glutamate dehydrogenase can reliably differentiate liver from muscle injury and, when serum is properly prepared, may also detect mitochondrial toxicity as a mechanism of liver injury. MicroRNA-122 is liver-specific, but recent data suggests it can be actively released from hepatocytes in the absence of overt toxicity limiting enthusiasm for it as a DILI biomarker. Finally, damage associated molecular patterns, particularly high mobility group box 1 and its various modified forms, are promising biomarkers of innate immune activation, which may be useful in distinguishing benign elevations in aminotransferases from those that portend clinically important liver injury. These new biomarkers are already being measured in early clinical trials, but broad acceptance will require widespread archiving of serum from diverse clinical trials and probably pre-competitive analysis efforts. We believe that utilization of a panel of traditional and newer biomarkers in conjunction with quantitative systems pharmacology modelling approaches will transform DILI detection and risk management.

Dose-dependent acute liver injury with hypersensitivity features in humans due to a novel microsomal prostaglandin E synthase 1 inhibitor

AIMS

LY3031207, a novel microsomal prostaglandin E synthase 1 inhibitor, was evaluated in a multiple ascending dose study after nonclinical toxicology studies and a single ascending dose study demonstrated an acceptable toxicity, safety and tolerability profile.

METHODS

Healthy subjects were randomized to receive LY3031207 (25, 75 and 275 mg), placebo or celecoxib (400 mg) once daily for 28 days. The safety, tolerability and pharmacokinetic and pharmacodynamic profiles of LY3031207 were evaluated.

RESULTS

The study was terminated when two subjects experienced drug-induced liver injury (DILI) after they had received 225 mg LY3031207 for 19 days. Liver biopsy from these subjects revealed acute liver injury with eosinophilic infiltration. Four additional DILI cases were identified after LY3031207 dosing had been stopped. All six DILI cases shared unique presentations of hepatocellular injury with hypersensitivity features and demonstrated a steep dose-dependent trend. Prompt discontinuation of the study drug and supportive medical care resulted in full recovery. Metabolites from metabolic activation of the imidazole ring were observed in plasma and urine samples from all subjects randomized to LY3031207 dosing.

CONCLUSIONS

This study emphasized the importance of careful safety monitoring and serious adverse events management in phase I trials. Metabolic activation of the imidazole ring may be involved in the development of hepatotoxicity of LY3031207.

Drug-induced liver injury due to antibiotics

Drug-induced liver injury (DILI) is an important differential diagnosis in patients with abnormal liver tests and normal hepatobiliary imaging. Of all known liver diseases, the diagnosis of DILI is probably one of the most difficult one to be established. In all major studies on DILI, antibiotics are the most common type of drugs that have been reported. The clinical phenotype of different types of antibiotics associated with liver injury is highly variable. Some widely used antibiotics such as amoxicillin-clavulanate have been shown to have a delayed onset on liver injury and recently cefazolin has been found to lead to liver injury 1-3 weeks after exposure of a single infusion. The other extreme is the nature of nitrofurantoin-induced liver injury, which can occur after a few years of treatment and lead to acute liver failure (ALF) or autoimmune-like reaction. Most patients with liver injury associated with use of antibiotics have a favorable prognosis. However, patients with jaundice have approximately 10% risk of death from liver failure and/or require liver transplantation. In rare instances, the hepatoxicity can lead to chronic injury and vanishing bile duct syndrome. Given, sometimes very severe consequences of the adverse liver reactions, it cannot be over emphasized that the indication for the different antibiotics should be evidence-based and symptoms and signs of liver injury from the drugs should lead to prompt cessation of therapy.

Drug-induced cholestasis

Cholestatic drug-induced liver injury (DILI) can be a diagnostic challenge due to a large differential diagnosis, variability in clinical presentation, and lack of serologic biomarkers associated with this condition. The clinical presentation of drug-induced cholestasis includes bland cholestasis, cholestatic hepatitis, secondary sclerosing cholangitis, and vanishing bile duct syndrome. The associate mortality of cholestatic DILI can be as high as 10%, and thus prompt recognition and removal of the offending agent is of critical importance. Several risk factors have been identified for drug-induced cholestasis, including older age, genetic determinants, and properties of certain medications. Antibiotics, particularly amoxicillin/clavulanate, remain the predominant cause of cholestatic DILI, although a variety of other medications associated with this condition have been identified. In this review, we summarize the presentation, clinical approach, risk factors, implicated medications, and management of drug-induced cholestatic liver injury. (Hepatology Communications 2017;1:726-735).

"Autoimmune(-Like)" Drug and Herb Induced Liver Injury: New Insights into Molecular Pathogenesis

Idiosyncratic drug-induced liver injury (DILI) and hepatic injury due to herbal and dietary supplements (HDS) can adapt clinical characteristics of autoimmune hepatitis (AIH), such as the appearance of autoantibodies and infiltration of the liver by immune competent cells. To describe these cases of DILI/HDS, the poorly-defined term "autoimmune(-like)" DILI/HDS came up. It is uncertain if these cases represent a subgroup of DILI/HDS with distinct pathomechanistic and prognostic features different from "classical" DILI/HDS. Besides, due to the overlap of clinical characteristics of "immune-mediated" DILI/HDS and AIH, both entities are not easy to differentiate. However, the demarcation is important, especially with regard to treatment: AIH requires long-term, mostly lifelong immunosuppression, whereas DILI/HDS does not. Only through exact diagnostic evaluation, exclusion of differential diagnoses and prolonged follow-up can the correct diagnosis reliably be made. Molecular mechanisms have not been analysed for the subgroup of "autoimmune(-like)" DILI/HDS yet. However, several pathogenetic checkpoints of DILI/HDS in general and AIH are shared. An analysis of these shared mechanisms might hint at relevant molecular processes of "autoimmune(-like)" DILI/HDS.

Drug rechallenge following drug-induced liver injury

Drug-induced hepatocellular injury is identified internationally by alanine aminotransferase (ALT) levels equal to or exceeding 5× the upper limit of normal (ULN) appearing within 3 months of drug initiation, after alternative causes are excluded. Upon withdrawing the suspect drug, ALT generally decrease by 50% or more. With drug readministration, a positive rechallenge has recently been defined by an ALT level of 3-5× ULN or greater. Nearly 50 drugs are associated with positive rechallenge after drug-induced liver injury (DILI): antimicrobials; and central nervous system, cardiovascular and oncology therapeutics. Drugs associated with high rates of positive rechallenge exhibit multiple risk factors: daily dose >50 mg, an increased incidence of ALT elevations in clinical trials, immunoallergic clinical injury, and mitochondrial impairment in vitro. These drug factors interact with personal genetic, immune, and metabolic factors to influence positive rechallenge rates and outcomes. Drug rechallenge following drug-induced liver injury is associated with up to 13% mortality in prospective series of all prescribed drugs. In recent oncology trials, standardized systems have enabled safer drug rechallenge with weekly liver chemistry monitoring during the high-risk period and exclusion of patients with hypersensitivity. However, high positive rechallenge rates with other innovative therapeutics suggest that caution should be taken with rechallenge of high-risk drugs.

CONCLUSION

For critical medicines, drug rechallenge may be appropriate when 1) no safer alternatives are available, 2) the objective benefit exceeds the risk, and 3) patients are fully informed and consent, can adhere to follow-up, and alert providers to hepatitis symptoms. To better understand rechallenge outcomes and identify key risk factors for positive rechallenge, additional data are needed from controlled clinical trials, prospective registries, and large health care databases. (Hepatology 2017;66:646-654).

Establishment of a mouse model of enalapril-induced liver injury and investigation of the pathogenesis

Drug-induced liver injury (DILI) is a major concern in drug development and clinical drug therapy. Since the underlying mechanisms of DILI have not been fully understood in most cases, elucidation of the hepatotoxic mechanisms of drugs is expected. Although enalapril (ELP), an angiotensin-converting enzyme inhibitor, has been reported to cause liver injuries with a low incidence in humans, the precise mechanisms by which ELP causes liver injury remains unknown. In this study, we established a mouse model of ELP-induced liver injury and analyzed the mechanisms of its hepatotoxicity. Mice that were administered ELP alone did not develop liver injury, and mice that were pretreated with a synthetic glucocorticoid dexamethasone (DEX) and a glutathione synthesis inhibitor l-buthionine-(S,R)-sulfoximine (BSO) exhibited liver steatosis without significant increase in plasma alanine aminotransferase (ALT). In mice pretreated with DEX and BSO, ALT levels were significantly increased after ELP administration, suggesting that hepatic steatosis sensitized the liver to ELP hepatotoxicity. An immunohistochemical analysis showed that the numbers of myeloperoxidase-positive cells that infiltrated the liver were significantly increased in the mice administered DEX/BSO/ELP. The levels of oxidative stress-related factors, including hepatic heme oxygenase-1, serum hydrogen peroxide and hepatic malondialdehyde, were elevated in the mice administered DEX/BSO/ELP. The involvement of oxidative stress in ELP-induced liver injury was further supported by the observation that tempol, an antioxidant agent, ameliorated ELP-induced liver injury. In conclusion, we successfully established a model of ELP-induced liver injury in DEX-treated steatotic mice and demonstrated that oxidative stress and neutrophil infiltration are involved in the pathogenesis of ELP-induced liver injury.

Idiosyncratic drug-induced liver injury: A short review

Idiosyncratic drug‐induced liver injury (iDILI) is a rare adverse drug reaction that occasionally leads to acute liver failure or even death. An aging population that uses more drugs, a constant influx of newly developed drugs, and a growing risk from herbal and dietary supplements of uncertain quality can lead to an increase in iDILI. Antimicrobials, central nervous system agents, and herbal and dietary supplements are the most common causes of iDILI in developed countries. iDILI is still a diagnosis of exclusion, and thus careful history taking and thorough work‐ups for competing etiologies, such as acute viral hepatitis, autoimmune hepatitis, and others, are essential. The pathogenesis of iDILI is not clear and includes a mix of host reactions, drug metabolites, and environmental factors. Immediate cessation of the suspected offending drug is key to preventing or minimizing progressive damage. No definitive therapies for iDILI are available, and the treatments remain largely supportive. (Hepatology Communications 2017;1:494–500)

Bile Salt Homeostasis in Normal and Bsep Gene Knockout Rats with Single and Repeated Doses of Troglitazone

The interference of bile acid secretion through bile salt export pump (BSEP) inhibition is one of the mechanisms for troglitazone (TGZ)-induced hepatotoxicity. Here, we investigated the impact of single or repeated oral doses of TGZ (200 mg/kg/day, 7 days) on bile acid homoeostasis in wild-type (WT) and Bsep knockout (KO) rats. Following oral doses, plasma exposures of TGZ were not different between WT and KO rats, and were similar on day 1 and day 7. However, plasma exposures of the major metabolite, troglitazone sulfate (TS), in KO rats were 7.6- and 9.3-fold lower than in WT on day 1 and day 7, respectively, due to increased TS biliary excretion. With Bsep KO, the mRNA levels of multidrug resistance-associated protein 2 (Mrp2), Mrp3, Mrp4, Mdr1, breast cancer resistance protein (Bcrp), sodium taurocholate cotransporting polypeptide, small heterodimer partner, and Sult2A1 were significantly altered in KO rats. Following seven daily TGZ treatments, Cyp7A1 was significantly increased in both WT and KO rats. In the vehicle groups, plasma exposures of individual bile acids demonstrated variable changes in KO rats as compared with WT. WT rats dosed with TGZ showed an increase of many bile acid species in plasma on day 1, suggesting the inhibition of Bsep. Conversely, these changes returned to base levels on day 7. In KO rats, alterations of most bile acids were observed after seven doses of TGZ. Collectively, bile acid homeostasis in rats was regulated through bile acid synthesis and transport in response to Bsep deficiency and TGZ inhibition. Additionally, our study is the first to demonstrate that repeated TGZ doses can upregulate Cyp7A1 in rats.

Associations of Drug Lipophilicity and Extent of Metabolism with Drug-Induced Liver Injury

Drug-induced liver injury (DILI), although rare, is a frequent cause of adverse drug reactions resulting in warnings and withdrawals of numerous medications. Despite the research community's best efforts, current testing strategies aimed at identifying hepatotoxic drugs prior to human trials are not sufficiently powered to predict the complex mechanisms leading to DILI. In our previous studies, we demonstrated lipophilicity and dose to be associated with increased DILI risk and, and in our latest work, we factored reactive metabolites into the algorithm to predict DILI. Given the inconsistency in determining the potential for drugs to cause DILI, the present study comprehensively assesses the relationship between DILI risk and lipophilicity and the extent of metabolism using a large published dataset of 1036 Food and Drug Administration (FDA)-approved drugs by considering five independent DILI annotations. We found that lipophilicity and the extent of metabolism alone were associated with increased risk for DILI. Moreover, when analyzed in combination with high daily dose (≥100 mg), lipophilicity was statistically significantly associated with the risk of DILI across all datasets (p < 0.05). Similarly, the combination of extensive hepatic metabolism (≥50%) and high daily dose (≥100 mg) was also strongly associated with an increased risk of DILI among all datasets analyzed (p < 0.05). Our results suggest that both lipophilicity and the extent of hepatic metabolism can be considered important risk factors for DILI in humans, and that this relationship to DILI risk is much stronger when considered in combination with dose. The proposed paradigm allows the convergence of different published annotations to a more uniform assessment.

Metabolomic approaches in the discovery of potential urinary biomarkers of drug-induced liver injury (DILI)

Drug-induced liver injury (DILI) is a major safety issue during drug development, as well as the most common cause for the withdrawal of drugs from the pharmaceutical market. The identification of DILI biomarkers is a labor-intensive area. Conventional biomarkers are not specific and often only appear at significant levels when liver damage is substantial. Therefore, new biomarkers for early identification of hepatotoxicity during the drug discovery process are needed, thus resulting in lower development costs and safer drugs. In this sense, metabolomics has been increasingly playing an important role in the discovery of biomarkers of liver damage, although the characterization of the mechanisms of toxicity induced by xenobiotics remains a huge challenge. These new-generation biomarkers will offer obvious benefits for the pharmaceutical industry, regulatory agencies, as well as a personalized clinical follow-up of patients, upon validation and translation into clinical practice or approval for routine use. This review describes the current status of the metabolomics applied to the early diagnosis and prognosis of DILI and in the discovery of new potential urinary biomarkers of liver injury.

Evaluation of DILI Predictive Hypotheses in Early Drug Development

Drug-induced liver injury (DILI) is a leading cause of drug failure in clinical trials and a major reason for drug withdrawals. DILI has been shown to be dependent on both daily dose and extent of hepatic metabolism. Yet, early in drug development daily dose is unknown. Here, we perform a comprehensive analysis of the published hypotheses that attempt to predict DILI, including a new analysis of the Biopharmaceutics Drug Disposition Classification System (BDDCS) in evaluating the severity of DILI warnings in drug labels approved by the FDA and the withdrawal status due to adverse drug reactions (ADRs). Our analysis confirms that higher doses ≥50 mg/day lead to increased DILI potential, but this property alone is not sufficient to predict the DILI potential. We evaluate prior attempts to categorize DILI such as Rule of 2, BSEP inhibition, and measures of key mechanisms of toxicity compared to BDDCS classification. Our results show that BDDCS Class 2 drugs exhibit the highest DILI severity and that all of the published methodologies evaluated here, except when daily dose is known, do not yield markedly better predictions than BDDCS. The assertion that extensive metabolized compounds are at higher risk of developing DILI is confirmed but can be enhanced by differentiating BDDCS Class 2 from Class 1 drugs. We do not propose that the BDDCS classification, which does not require knowledge of the clinical dose, is sufficiently predictive/accurate of DILI potential for new molecular entities but suggest that comparison of proposed DILI prediction methodologies with BDDCS classification is a useful tool to evaluate the potential reliability of newly proposed algorithms.

CONCLUSION

The most successful approaches to predict DILI potential all include a measure of dose, yet there is a quantifiable uncertainty associated with the predicted dose early in drug development. Here, we compare the possibility of predicting DILI potential using the BDDCS classification versus previously published methods and note that many hypothesized predictive DILI metrics do no better than just avoiding BDDCS Class 2 drugs.

Evaluation of a human in vitro hepatocyte-NPC co-culture model for the prediction of idiosyncratic drug-induced liver injury: A pilot study

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Co-cultures of liver and immune cells can be used to detect iDILI compounds.

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Pro-inflammatory factors are involved in the development of iDILI.

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The co-exposure of a drug candidate with TNF might be sufficient to predict iDILI.

Interactions between hepatocytes and immune cells as well as inflammatory episodes are frequently discussed to play a critical role in the alteration of the individual susceptibility to idiosyncratic drug-induced liver injury (iDILI). To evaluate this hypothesis and to face the urgent need for predictive in vitro models, we established two co-culture systems based on two human cell lines in presence or absence of pro-inflammatory factors (LPS, TNF), i.e. hepatoma HepG2 cells co-cultured with monocytic or macrophage-like THP-1 cells. HepG2 monocultures served as control scenario. Mono- or co-cultures were treated with iDILI reference substances (Troglitazone [TGZ], Trovafloxacin [TVX], Diclofenac [DcL], Ketoconazole [KC]) or their non-iDILI partner compounds (Rosiglitazone, Levofloxacin, Acetylsalicylic Acid, Fluconazole). The liver cell viability was subsequently determined via WST-Assay. An enhanced cytotoxicity (synergy) or a hormetic response compared to the drug effect in the HepG2 monoculture was considered as iDILI positive. TGZ synergized in co-cultures with monocytes without an additional pro-inflammatory stimulus, while DcL and KC showed a hormetic response. All iDILI drugs synergized with TNF in the simple HepG2 monoculture, indicating its relevance as an initiator of iDILI. KC showed a synergy when co-exposed to both, monocytes and LPS, while TVX and DcL showed a synergy under the same conditions with macrophages. All described iDILI responses were not observed with the corresponding non-iDILI partner compounds. Our first results confirm that an inflammatory environment increases the sensitivity of liver cells towards iDILI compounds and point to an involvement of pro-inflammatory factors, especially TNF, in the development of iDILI.

Psychotropic drugs and liver disease: A critical review of pharmacokinetics and liver toxicity

The liver is the organ by which the majority of substances are metabolized, including psychotropic drugs. There are several pharmacokinetic changes in end-stage liver disease that can interfere with the metabolization of psychotropic drugs. This fact is particularly true in drugs with extensive first-pass metabolism, highly protein bound drugs and drugs depending on phase I hepatic metabolic reactions. Psychopharmacological agents are also associated with a risk of hepatotoxicity. The evidence is insufficient for definite conclusions regarding the prevalence and severity of psychiatric drug-induced liver injury. High-risk psychotropics are not advised when there is pre-existing liver disease, and after starting a psychotropic agent in a patient with hepatic impairment, frequent liver function/lesion monitoring is advised. The authors carefully review the pharmacokinetic disturbances induced by end-stage liver disease and the potential of psychopharmacological agents for liver toxicity.

In Silico Identification of Proteins Associated with Drug-induced Liver Injury Based on the Prediction of Drug-target Interactions

Drug-induced liver injury (DILI) is the leading cause of acute liver failure as well as one of the major reasons for drug withdrawal from clinical trials and the market. Elucidation of molecular interactions associated with DILI may help to detect potentially hazardous pharmacological agents at the early stages of drug development. The purpose of our study is to investigate which interactions with specific human protein targets may cause DILI. Prediction of interactions with 1534 human proteins was performed for the dataset with information about 699 drugs, which were divided into three categories of DILI: severe (178 drugs), moderate (310 drugs) and without DILI (211 drugs). Based on the comparison of drug-target interactions predicted for different drugs' categories and interpretation of those results using clustering, Gene Ontology, pathway and gene expression analysis, we identified 61 protein targets associated with DILI. Most of the revealed proteins were linked with hepatocytes' death caused by disruption of vital cellular processes, as well as the emergence of inflammation in the liver. It was found that interaction of a drug with the identified targets is the essential molecular mechanism of the severe DILI for the most of the considered pharmaceuticals. Thus, pharmaceutical agents interacting with many of the identified targets may be considered as candidates for filtering out at the early stages of drug research.

Mechanisms of Drug-Induced Hepatotoxicity

Drug-induced hepatotoxicity (DIH) is a significant cause of acute liver failure and liver transplantation. Diagnosis is challenging due to the idiosyncratic nature, its presentation in the form of other liver disease, and the lack of a definite diagnostic criteria. Generation of reactive metabolites, oxidative stress, and mitochondrial dysfunction are common mechanisms involved in DIH. Certain risk factors associated with a drug and within an individual further predispose patients to DIH.

Adverse Drug Reactions: Type A (Intrinsic) or Type B (Idiosyncratic)

Hepatotoxic adverse drug reactions are associated with significant morbidity and mortality and are the leading cause of postmarketing regulatory action in the United States. They are classified as Type A (intrinsic) or Type B (idiosyncratic). Type A are predictable, dose-related toxicities, often identified in preclinical or clinical trials, and usually occur in overdose settings or with pre-existing hepatic impairment. Type B are not clearly related to increasing dose and are associated with drug-specific and patient-specific characteristics and environmental risks. Rare Type B reactions are often identified postmarketing. Identification and management, including electronic resources, has evolved.

Hepatotoxicity of statins and other lipid-lowering agents

Statins are generally well tolerated and adverse effects are relatively rare. Clinical trials are underpowered to detect uncommon adverse effects such as idiosyncratic drug-induced liver injury. This review is aimed at covering the current knowledge on the hepatotoxicity associated with statins and other lipid lowering drugs. Both atorvastatin and simvastatin have been associated with more than 50 case reports of liver injury and other statins have been implicated in this type of liver injury as well. Idiosyncratic liver injury due to statins has been reported to occur 1.9%-5.5% of patients in prospective series of drug-induced liver injury. Atorvastatin and simvastatin have been associated with positive rechallenge and some case reports have described liver injury following dose escalation of the implicated statin. Mortality from liver injury and/or liver transplantation has been documented in a few patients with statin induced liver injury although the vast majority of patients with liver injury have recovered after cessation of therapy.

Epidemiology and Genetic Risk Factors of Drug Hepatotoxicity

Idiosyncratic drug-induced liver injury (DILI) from prescription medications and herbal and dietary supplements has an annual incidence rate of approximately 20 cases per 100,000 per year. However, the risk of DILI varies greatly according to the drug. In the United States and Europe, antimicrobials are the commonest implicated agents, with amoxicillin/clavulanate the most common, whereas in Asian countries, herbal and dietary supplements predominate. Genetic analysis of DILI is currently limited, but multiple polymorphisms of human leukocyte antigen genes and genes involved in drug metabolism and transport have been identified as risk factors for DILI.

Diphenhydramine as a Cause of Drug-Induced Liver Injury

Drug-induced liver injury (DILI) is the most common cause of acute liver failure in the Unites States and accounts for 10% of acute hepatitis cases. We report the only known case of diphenhydramine-induced acute liver injury in the absence of concomitant medications. A 28-year-old man with history of 13/14-chromosomal translocation presented with fevers, vomiting, and jaundice. Aspartate-aminotransferase and alanine-aminotransferase levels peaked above 20,000 IU/L and 5,000 IU/L, respectively. He developed coagulopathy but without altered mental status. Patient reported taking up to 400 mg diphenhydramine nightly, without concomitant acetaminophen, for insomnia. He denied taking other medications, supplements, antibiotics, and herbals. A thorough workup of liver injury ruled out viral hepatitis (including A, B, C, and E), autoimmune, toxic, ischemic, and metabolic etiologies including Wilson's disease. A liver biopsy was consistent with DILI without evidence of iron or copper deposition. Diphenhydramine was determined to be the likely culprit. This is the first reported case of diphenhydramine-induced liver injury without concomitant use of acetaminophen.

Patient-specific hepatocyte-like cells derived from induced pluripotent stem cells model pazopanib-mediated hepatotoxicity

Idiosyncratic drug-induced hepatotoxicity is a major cause of liver damage and drug pipeline failure, and is difficult to study as patient-specific features are not readily incorporated in traditional hepatotoxicity testing approaches using population pooled cell sources. Here we demonstrate the use of patient-specific hepatocyte-like cells (HLCs) derived from induced pluripotent stem cells for modeling idiosyncratic hepatotoxicity to pazopanib (PZ), a tyrosine kinase inhibitor drug associated with significant hepatotoxicity of unknown mechanistic basis. In vitro cytotoxicity assays confirmed that HLCs from patients with clinically identified hepatotoxicity were more sensitive to PZ-induced toxicity than other individuals, while a prototype hepatotoxin acetaminophen was similarly toxic to all HLCs studied. Transcriptional analyses showed that PZ induces oxidative stress (OS) in HLCs in general, but in HLCs from susceptible individuals, PZ causes relative disruption of iron metabolism and higher burden of OS. Our study establishes the first patient-specific HLC-based platform for idiosyncratic hepatotoxicity testing, incorporating multiple potential causative factors and permitting the correlation of transcriptomic and cellular responses to clinical phenotypes. Establishment of patient-specific HLCs with clinical phenotypes representing population variations will be valuable for pharmaceutical drug testing.

Exposure to reactive intermediate-inducing drugs during pregnancy and the incident use of psychotropic medications among children

PURPOSE

Our study aimed to investigate the association between prenatal exposure to reactive intermediate (RI)-inducing drugs and the initiation of psychotropic medications among children.

METHODS

We designed a cohort study using a pharmacy prescription database. Pregnant women were considered exposed when they received a prescription of RI-inducing drugs. These drugs could be either used alone (RI+/FAA-) or combined with drugs exhibiting folic acid antagonism (FAA, RI+/FAA+). The reference group included pregnant women who did not receive any RI-inducing drugs or FAA drugs.

RESULTS

We analyzed 4116 exposed and 30 422 reference pregnancies. The hazard ratio (HR) with 95% confidence interval (CI) was 1.27 (95%CI 1.15-1.41) for pregnancies exposed to RI-inducing drugs as a whole. Considering subgroups of RI-inducing drugs, prenatal exposure to both RI+/FAA+ and RI+/FAA- was associated with the children's initiation of psychotropic medications, HRs being 1.35 (95%CI 1.10-1.66) and 1.26 (1.13-1.41), respectively. The HRs were increased with prolonged exposure to RI-inducing drugs, especially in the first and second trimesters. In a detailed examination of the psychotropics, the incidences of receiving antimigraine preparations and psychostimulants were significantly increased for the exposed children, compared with the reference children. The incidences of receiving antipsychotics and hypnotics were also higher for the exposed children; however, the HRs did not reach significance after adjustment.

CONCLUSIONS

We found a significantly increased incident use of psychotropic medications among children prenatally exposed to RI-inducing drugs, especially during the first and second trimesters. This suggests a detrimental effect during critical periods of brain development. Copyright © 2017 John Wiley & Sons, Ltd.

Azathioprine and 6-Mercaptopurine-induced Liver Injury: Clinical Features and Outcomes

OBJECTIVE

The objective of the study was to define the clinical, biochemical, and histologic features of liver injury from thiopurines.

BACKGROUND

Azathioprine (Aza) and 6-mercaptopurine (6-MP) can cause liver injury, but no large series exist.

METHODS

Clinical and laboratory data and 6-month outcomes of patients with thiopurine hepatotoxicity from the Drug-Induced Liver Injury Network Prospective Study were analyzed.

RESULTS

Twenty-two patients were identified, 12 due to Aza and 10 due to 6-MP, with a median age of 55 years; the majority were female (68%). Inflammatory bowel disease was the indication in 55%, and the median thiopurine dose was 150 (range, 25 to 300) mg daily. The median latency to onset was 75 (range, 3 to 2584) days. Injury first arose after a dose escalation in 59% of patients, the median latency after dose increase being 44 (range, 3 to 254) days. At onset, the median alanine aminotransferase level was 210 U/L, alkaline phosphatase was 151 U/L, and bilirubin was 7.4 mg/dL (peak, 13.4 mg/dL). There were no major differences between Aza and 6-MP cases, but anicteric cases typically had nonspecific symptoms and a hepatocellular pattern of enzyme elevations, whereas icteric cases experienced cholestatic hepatitis with modest enzyme elevations in a mixed pattern. One patient with preexisting cirrhosis required liver transplantation; all others resolved clinically. One patient still had moderate alkaline phosphatase elevations 2 years after onset.

CONCLUSIONS

Nearly three-quarters of patients with thiopurine-induced liver injury present with self-limited, cholestatic hepatitis, typically within 3 months of starting or a dose increase. The prognosis is favorable except in patients with preexisting cirrhosis.

Mechanism of Hepatocyte Apoptosis

Hepatocyte apoptosis plays important roles in both the removal of external microorganisms and the occurrence and development of liver diseases. Different conditions, such as virus infection, fatty liver disease, hepatic ischemia reperfusion, and drug-induced liver injury, are accompanied by hepatocyte apoptosis. This review summarizes recent research on the mechanism of hepatocyte apoptosis involving the classical extrinsic and intrinsic apoptotic pathways, endoplasmic reticulum stress, and oxidative stress-induced apoptosis. We emphasized the major causes of apoptosis according to the characteristics of different liver diseases. Several concerns regarding future research and clinical application are also raised.

Drug-induced liver injury

Drug-induced liver injury (DILI) remains the most common cause of acute liver failure (ALF) in the western world. Excluding paracetamol overdose, nearly all DILI encountered in the clinical setting is idiosyncratic in nature because affected individuals represent only a small proportion of those treated with such drugs. In many cases, the mechanism for idiosyncrasy is immune-mediation and is often identified by genetic risk determined by human leukocyte antigen variants. In the absence of diagnostic tests and/or biomarkers, the diagnosis of DILI requires a high index of suspicion after diligently excluding other causes of abnormal liver tests. Antibiotics are the class of drugs most frequently associated with idiosyncratic DILI, although recent studies indicate that herbal and dietary supplements are an increasingly recognised cause. It is imperative that upon development of DILI the culprit drug be discontinued, especially in the presence of elevated transaminases (aspartate aminotransferase/alanine aminotransferase ratio ≥5 times the upper limit of normal) and/or jaundice. Risk factors for the development ALF include hepatocellular DILI and female gender, the treatment being supportive with some benefit of N-acetylcysteine in the early stages. In view of the poor transplant-free survival in idiosyncratic DILI, early consideration for liver transplant is mandatory.

Elevated Liver Enzymes: Emergency Department-Focused Management

BACKGROUND

Liver function test (LFT) abnormalities are a common problem faced by emergency physicians. This has become more common with the introduction of laboratory panels and automated routine laboratory testing. Fortunately, not all patients with irregularities in liver enzymes possess underlying pathology. This emergency medicine focused review provides a discussion of the various biochemical tests, their underlying biological basis, and an algorithmic approach to the interpretation of abnormalities.

OBJECTIVE

Our aim was to provide emergency physicians with an overview of the evaluation and management of patients with elevated LFTs.

DISCUSSION

The liver is a complex organ with multiple roles. The key biochemical markers of hepatic function can be organized into the groupings of hepatocellular, cholestatic, or functioning liver, based on underlying enzymatic roles. Pathologic alterations to these markers can be algorithmically assessed by separating disease processes of these groupings, followed by assessment of the magnitude of enzymatic elevation. This review conducts an in-depth evaluation of the differential diagnosis and emergency department-centered clinical response of elevated LFTs based on subcategories of mild, moderate, and severe transaminase elevation.

CONCLUSIONS

By understanding the biochemical basis of each LFT, it is possible to correlate laboratory findings to a patient's clinical presentation. An algorithmic approach can be taken to help narrow the spectrum of a differential diagnosis. This may assist providers in ensuring appropriate management and evaluation of the patient with elevated LFTs.

Drug-induced liver injury: Is chronic liver disease a risk factor and a clinical issue?

INTRODUCTION

Clinicians and practitioners caring for patients with chronic liver disease are often unsure whether drug therapy is a hazard that increases their patient's risk for drug-induced liver injury (DILI). Areas covered: We searched for reports of drug induced liver injury, both idiosyncratic and intrinsic, in patients with chronic liver disease including non-alcoholic and alcoholic liver disease, and cirrhosis. Reports we analyzed include statin treatment in patients with fatty liver, acetaminophen use in alcoholic fatty liver, antituberculous drugs in patients with tuberculosis and viral hepatitis, antiviral medications in hepatitis and antiretroviral medications in HIV/AIDS. The most challenging cases we found are drug therapy in patients with decompensated liver cirrhosis. Expert opinion: We identified many case reports and case series discussing a potential increased risk of DILI in patients with pre-existing liver disease. However, most of these reports were retrospective and ambiguous. With few exceptions, we conclude that drugs seem to be well tolerated by the majority of patients with pre-existing, non-cirrhotic chronic liver diseases. Special care is needed for some therapies, however, including antiviral therapy in chronic hepatitis B and C and in decompensated liver cirrhosis with impaired drug metabolism. Prospective studies are warranted to valid our conclusions.

A Perspective on the Kinetics of Covalent and Irreversible Inhibition

The clinical and commercial success of covalent drugs has prompted a renewed and more deliberate pursuit of covalent and irreversible mechanisms within drug discovery. A covalent mechanism can produce potent inhibition in a biochemical, cellular, or in vivo setting. In many cases, teams choose to focus on the consequences of the covalent event, defined by an IC₅₀ value. In a biochemical assay, the IC₅₀ may simply reflect the target protein concentration in the assay. What has received less attention is the importance of the rate of covalent modification, defined by k_inact/K_I. The k_inact/K_I is a rate constant describing the efficiency of covalent bond formation resulting from the potency (K_I) of the first reversible binding event and the maximum potential rate (k_inact) of inactivation. In this perspective, it is proposed that the k_inact/K_I should be employed as a critical parameter to identify covalent inhibitors, interpret structure-activity relationships (SARs), translate activity from biochemical assays to the cell, and more accurately define selectivity. It is also proposed that a physiologically relevant k_inact/K_I and an (unbound) AUC generated from a pharmacokinetic profile reflecting direct exposure of the inhibitor to the target protein are two critical determinants of in vivo covalent occupancy. A simple equation is presented to define this relationship and improve the interpretation of covalent and irreversible kinetics.

Key Challenges and Opportunities Associated with the Use of In Vitro Models to Detect Human DILI: Integrated Risk Assessment and Mitigation Plans

Drug-induced liver injury (DILI) is a major cause of late-stage clinical drug attrition, market withdrawal, black-box warnings, and acute liver failure. Consequently, it has been an area of focus for toxicologists and clinicians for several decades. In spite of considerable efforts, limited improvements in DILI prediction have been made and efforts to improve existing preclinical models or develop new test systems remain a high priority. While prediction of intrinsic DILI has improved, identifying compounds with a risk for idiosyncratic DILI (iDILI) remains extremely challenging because of the lack of a clear mechanistic understanding and the multifactorial pathogenesis of idiosyncratic drug reactions. Well-defined clinical diagnostic criteria and risk factors are also missing. This paper summarizes key data interpretation challenges, practical considerations, model limitations, and the need for an integrated risk assessment. As demonstrated through selected initiatives to address other types of toxicities, opportunities exist however for improvement, especially through better concerted efforts at harmonization of current, emerging and novel in vitro systems or through the establishment of strategies for implementation of preclinical DILI models across the pharmaceutical industry. Perspectives on the incorporation of newer technologies and the value of precompetitive consortia to identify useful practices are also discussed.

A Model to predict severity of drug-induced liver injury in humans

Drug-induced liver injury (DILI) is a major public health concern, and improving its prediction remains an unmet challenge. Recently, we reported the Rule-of-2 (RO2) and found lipophilicity (logP ≥3) and daily dose ≥100 mg of oral medications to be associated with significant risk for DILI; however, the RO2 failed to estimate grades of DILI severity. In an effort to develop a quantitative metrics, we analyzed the association of daily dose, logP, and formation of reactive metabolites (RM) in a large set of Food and Drug Administration-approved oral medications and found factoring RM into the RO2 to highly improve DILI prediction. Based on these parameters and by considering n = 354 drugs, an algorithm to assign a DILI score was developed. In univariate and multivariate logistic regression analyses the algorithm (i.e., DILI score model) defined the relative contribution of daily dose, logP, and RM and permitted a quantitative assessment of risk of clinical DILI. Furthermore, a clear relationship between calculated DILI scores and DILI risk was obtained when applied to three independent studies. The DILI score model was also functional with drug pairs defined by similar chemical structure and mode of action but divergent toxicities. Specifically, for drug pairs where the RO2 failed, the DILI score correctly identified toxic drugs. Finally, the model was applied to n = 159 clinical cases collected from the National Institutes of Health's LiverTox database to demonstrate that the DILI score correlated with the severity of clinical outcome.

CONCLUSIONS

Based on daily dose, lipophilicity, and RM, a DILI score algorithm was developed that provides a scale of assessing the severity of DILI risk in humans associated with oral medications. (Hepatology 2016;64:931-940).

Characterisation of Agomelatine-Induced Increase in Liver Enzymes: Frequency and Risk Factors Determined from a Pooled Analysis of 7605 Treated Patients

BACKGROUND

Antidepressant-induced liver injury is a major concern and a liver monitoring scheme has been recommended by the European Medicines Agency for agomelatine.

OBJECTIVE

The objective of this study was to assess the liver safety and identify the characteristics of patients who developed a significant increase in transaminases whilst taking agomelatine.

METHOD

A retrospective pooled analysis of changes in transaminase levels in 9234 patients treated with agomelatine (25 or 50 mg/day; n = 7605) or placebo (n = 1629) from 49 phase II and III studies was undertaken. A significant increase in transaminase levels was defined as an increase to >3 times the upper limit of normal (ULN) (>3 × ULN). Final causality was determined in a case-by-case review by five academic experts.

RESULTS

Serum transaminases increased to >3 × ULN in 1.3 and 2.5 % of patients treated with 25 and 50 mg of agomelatine, respectively, compared with 0.5 % for placebo. The onset of increased transaminases occurred before 12 weeks in 64 % of patients. The median time to recovery (to ≤2 × ULN) was 14 days following treatment withdrawal. Liver function tests recovered in 36.1 % of patients despite continuation of agomelatine, suggesting the presence of a liver adaptive mechanism. No cases of acute liver failure or fatal outcome occurred. Patients with elevated transaminases at baseline, secondary to obesity/fatty liver disease, had an equally increased risk of developing further elevations of transaminases with agomelatine and placebo.

CONCLUSION

Incidence of abnormal transaminases was low and dose dependent. No specific population was identified regarding potential risk factors. Withdrawal of agomelatine led to rapid recovery, and some patients exhibited an adaptive phenomenon. Overall, in clinical trials, the liver profile of agomelatine seems safe when serum transaminases are monitored.

Traditional Chinese Medicine (TCM) and Herbal Hepatotoxicity: RUCAM and the Role of Novel Diagnostic Biomarkers Such as MicroRNAs

Background: Traditional Chinese Medicine (TCM) with its focus on herbal use is popular and appreciated worldwide with increased tendency, although its therapeutic efficacy is poorly established for most herbal TCM products. Treatment was perceived as fairly safe but discussions emerged more recently as to whether herb induced liver injury (HILI) from herbal TCM is a major issue; Methods: To analyze clinical and case characteristics of HILI caused by herbal TCM, we undertook a selective literature search in the PubMed database with the search items Traditional Chinese Medicine, TCM, alone and combined with the terms herbal hepatotoxicity or herb induced liver injury; Results: HILI caused by herbal TCM is rare and similarly to drugs can be caused by an unpredictable idiosyncratic or a predictable intrinsic reaction. Clinical features of liver injury from herbal TCM products are variable, and specific diagnostic biomarkers such as microsomal epoxide hydrolase, pyrrole-protein adducts, metabolomics, and microRNAs are available for only a few TCM herbs. The diagnosis is ascertained if alternative causes are validly excluded and causality levels of probable or highly probable are achieved applying the liver specific RUCAM (Roussel Uclaf Causality Assessment Method) as the most commonly used diagnostic tool worldwide. Case evaluation may be confounded by inappropriate or lacking causality assessment, poor herbal product quality, insufficiently documented cases, and failing to exclude alternative causes such as infections by hepatotropic viruses including hepatitis E virus infections; Conclusion: Suspected cases of liver injury from herbal TCM represent major challenges that deserve special clinical and regulatory attention to improve the quality of case evaluations and ascertain patients' safety and benefit.

A comprehensive study of the association between drug hepatotoxicity and daily dose, liver metabolism, and lipophilicity using 975 oral medications

It was recently suggested that daily dose, liver metabolism and lipophilicity were associated with an oral drug's potential to cause hepatotoxicity, but this has not been widely accepted. A likely reason is that published data lack comprehensiveness, as they were based on only about one third of all FDA approved single-active-ingredient oral prescription drugs. Here the 975 oral drugs used worldwide which have a Defined Daily Dose (DDD) designated in the World Health Organization's Anatomical Therapeutic Chemical classification system and whose hADRs potential and metabolism data are available in the Micromedex Drugdex^® compendium were studied, with their lipophilicity calculated by the partition coefficient LogP. Of the 975 drugs examined, 49% (478) have the potential to induce at least one type of hepatic adverse drug reactions (hADRs) such as fatal hepatotoxicity, acute liver failure, significant ALT/AST elevation, hepatitis, and jaundice. By single factor analysis, a higher DDD (≥100 mg) was found to be associated with all types of hADRs, and extensive liver metabolism (≥50%) was associated with a subset of hADRs including fatal hADRs, hepatitis and jaundice, while LogP showed no relation to any types of hADRs. Contrary to previous reports, none of the combination, neither DDD and liver metabolism, nor DDD and LogP, was found to be more predictive of hADRs than using DDD or liver metabolism alone. These data provide convincing evidence that a higher daily dose and extensive liver metabolism, but not lipophilicity, are independent but not synergistic risk factors for oral drugs to induce hepatotoxicity.

Case Characterization, Clinical Features and Risk Factors in Drug-Induced Liver Injury

Idiosyncratic drug-induced liver injury (DILI) caused by xenobiotics (drugs, herbals and dietary supplements) presents with a range of both phenotypes and severity, from acute hepatitis indistinguishable of viral hepatitis to autoimmune syndromes, steatosis or rare chronic vascular syndromes, and from asymptomatic liver test abnormalities to acute liver failure. DILI pathogenesis is complex, depending on the interaction of drug physicochemical properties and host factors. The awareness of risk factors for DILI is arising from the analysis of large databases of DILI cases included in Registries and Consortia networks around the world. These networks are also enabling in-depth phenotyping with the identification of predictors for severe outcome, including acute liver failure and mortality/liver transplantation. Genome wide association studies taking advantage of these large cohorts have identified several alleles from the major histocompatibility complex system indicating a fundamental role of the adaptive immune system in DILI pathogenesis. Correct case definition and characterization is crucial for appropriate phenotyping, which in turn will strengthen sample collection for genotypic and future biomarkers studies.

Hepatotoxicity of New Oral Anticoagulants (NOACs)

Case reports and analyses of clinical studies and of pharmacovigilance data suggest that new oral anticoagulants (NOACs) are associated with a small risk for hepatotoxicity. The objective of this publication is to summarize the current data about this subject, with a special emphasis on pharmacovigilance data in the World Health Organization (WHO) Global Individual Case Safety Reports (ICSR) database and on potential mechanisms of hepatotoxicity. For that, all available case reports as well as published analyses of clinical studies were obtained with a detailed search in PubMed. In addition, pharmacovigilance data from VigiBase(®), the WHO Global ICRS database, were extracted and analyzed. The data show that liver injury associated with NOACs was reported in clinical studies and in pharmacovigilance databases. Several case reports described potentially life-threatening hepatotoxicity in patients treated with rivaroxaban or dabigatran. For rivaroxaban, most affected patients were symptomatic and liver injury was most often hepatocellular or mixed. The frequency was between 0.1 and 1 % in clinical studies and was by trend lower than for comparators (mostly enoxaparin or warfarin). Comparing the pharmacovigilance reports for the individual NOACs, more hepatic adverse events were reported for rivaroxaban than for dabigatran or apixaban. With the exception of edoxaban, for which only few reports are available, patients with acute liver failure have been reported for every NOAC, but most patients had concomitant drugs or diseases. So far, there are no clear mechanisms explaining the hepatotoxicity of these drugs. We conclude that hepatotoxicity appears to be associated with all NOACs currently on the market. Hepatotoxicity associated with NOACs is idiosyncratic; it appears at therapeutic doses, is rare and the mechanism is not related to the pharmacological action of these drugs. Prescribers should inform patients about possible symptoms of hepatotoxicity and stop these drugs in patients presenting with severe liver injury.

Herbal Hepatotoxicity: Clinical Characteristics and Listing Compilation

Herb induced liver injury (HILI) and drug induced liver injury (DILI) share the common characteristic of chemical compounds as their causative agents, which were either produced by the plant or synthetic processes. Both, natural and synthetic chemicals are foreign products to the body and need metabolic degradation to be eliminated. During this process, hepatotoxic metabolites may be generated causing liver injury in susceptible patients. There is uncertainty, whether risk factors such as high lipophilicity or high daily and cumulative doses play a pathogenetic role for HILI, as these are under discussion for DILI. It is also often unclear, whether a HILI case has an idiosyncratic or an intrinsic background. Treatment with herbs of Western medicine or traditional Chinese medicine (TCM) rarely causes elevated liver tests (LT). However, HILI can develop to acute liver failure requiring liver transplantation in single cases. HILI is a diagnosis of exclusion, because clinical features of HILI are not specific as they are also found in many other liver diseases unrelated to herbal use. In strikingly increased liver tests signifying severe liver injury, herbal use has to be stopped. To establish HILI as the cause of liver damage, RUCAM (Roussel Uclaf Causality Assessment Method) is a useful tool. Diagnostic problems may emerge when alternative causes were not carefully excluded and the correct therapy is withheld. Future strategies should focus on RUCAM based causality assessment in suspected HILI cases and more regulatory efforts to provide all herbal medicines and herbal dietary supplements used as medicine with strict regulatory surveillance, considering them as herbal drugs and ascertaining an appropriate risk benefit balance.

Adverse drug reactions and organ damage: The liver

Drug-induced liver injury (DILI) is among the most challenging acute or chronic liver conditions to be handled by physicians. Despite its low incidence in the general population, DILI is a frequent cause of acute liver failure. As such, the possibility of DILI should be considered in all patients who present with acute liver damage, independent of any known pre-existing liver disease. DILI can be classified as intrinsic/dose-dependent (e.g., acetaminophen toxicity) or idiosyncratic/dose-independent, with the latter form being relatively uncommon. Amoxicillin-clavulanate is the antimicrobial that is most frequently associated with idiosyncratic DILI. Large, ongoing, prospective studies in western countries have reported other drugs associated with DILI, including nonsteroidal anti-inflammatory drugs, statins, and herbal and dietary supplements. An important safety issue, DILI is one of the most frequently cited reasons for cessation of drug development during or after preclinical studies and for withdrawal of a drug from the market. This review summarizes the epidemiology, risk factors, commonly implicated drugs, clinical features, and diagnosis of DILI, with the aim of aiding physicians in the management of this debated problem. Old and new biomarkers for DILI and pharmacogenetic studies are also described.

Systematic Review and Meta-Analysis: Macrolides- and Amoxicillin/Clavulanate-induced Acute Liver Injury

Antibacterials are frequently associated with idiosyncratic drug-induced liver injury (DILI). The objective of this study was to estimate the risk of macrolides and amoxicillin/clavulanate (AMC) on DILI. We conducted a systematic review (SR) and meta-analysis (MA) with studies retrieved from PubMed, Cochrane Library Plus, Web of Knowledge, clinicaltrials.gov, Livertox and Toxline (1980-2014). We searched for macrolides, AMC and MeSH and synonym terms for DILI. We included all study designs except case reports/series, all population ages and studies with a placebo/non-user comparator. We summarized the evidence with a random-effects MA. Quality of the studies was appraised with a checklist developed for SR of adverse effects. Heterogeneity and publication bias were assessed with different exploratory tools. We finally included 10 (two randomized clinical trials, six case-control, one cohort and one case-population studies) and 9 (case-population excluded) articles in the SR and MA, respectively. The overall summary relative risk of DILI for macrolides was 2.85 [95% confidence interval (CI) 1.81-4.47], p < 0.0001, I(2) = 57%. Three studies were perceived to be missing in the area of low statistical significance. Year of study and selected exposure window partly explained the variability between studies. For AMC, the risk of DILI was 9.38 (95% CI 0.65-135.41) p = 0.3, I2 = 95%. In conclusion, although spontaneous reports and case series have long established an association between macrolides and AMC with acute liver injury, these SR and MA have assessed the magnitude of this association. The low incidence of DILI and the therapeutic place of these antibiotics might tilt the balance in favour of their benefits.

The Need for Biomarkers in Diagnosis and Prognosis of Drug-Induced Liver Disease: Does Metabolomics Have Any Role?

Drug-induced liver injury (DILI) is a potentially fatal adverse event and the leading cause of acute liver failure in the US and in the majority of Europe. The liver can be affected directly, in a dose-dependent manner, or idiosyncratically, independently of the dose, and therefore unpredictably. Currently, DILI is a diagnosis of exclusion that physicians should suspect in patients with unexplained elevated liver enzymes. Therefore, new diagnostic and prognostic biomarkers are necessary to achieve an early and reliable diagnosis of DILI and thus improve the prognosis. Although several DILI biomarkers have been found through analytical and genetic tests and pharmacokinetic approaches, none of them have been able to display enough specificity and sensitivity, so new approaches are needed. In this sense, metabolomics is a strongly and promising emerging field that, from biofluids collected through minimally invasive procedures, can obtain early biomarkers of toxicity, which may constitute specific indicators of liver damage.

RUCAM in Drug and Herb Induced Liver Injury: The Update

RUCAM (Roussel Uclaf Causality Assessment Method) or its previous synonym CIOMS (Council for International Organizations of Medical Sciences) is a well established tool in common use to quantitatively assess causality in cases of suspected drug induced liver injury (DILI) and herb induced liver injury (HILI). Historical background and the original work confirm the use of RUCAM as single term for future cases, dismissing now the term CIOMS for reasons of simplicity and clarity. RUCAM represents a structured, standardized, validated, and hepatotoxicity specific diagnostic approach that attributes scores to individual key items, providing final quantitative gradings of causality for each suspect drug/herb in a case report. Experts from Europe and the United States had previously established in consensus meetings the first criteria of RUCAM to meet the requirements of clinicians and practitioners in care for their patients with suspected DILI and HILI. RUCAM was completed by additional criteria and validated, assisting to establish the timely diagnosis with a high degree of certainty. In many countries and for more than two decades, physicians, regulatory agencies, case report authors, and pharmaceutical companies successfully applied RUCAM for suspected DILI and HILI. Their practical experience, emerging new data on DILI and HILI characteristics, and few ambiguous questions in domains such alcohol use and exclusions of non-drug causes led to the present update of RUCAM. The aim was to reduce interobserver and intraobserver variability, to provide accurately defined, objective core elements, and to simplify the handling of the items. We now present the update of the well accepted original RUCAM scale and recommend its use for clinical, regulatory, publication, and expert purposes to validly establish causality in cases of suspected DILI and HILI, facilitating a straightforward application and an internationally harmonized approach of causality assessment as a common basic tool.

Is Liver Enzyme Release Really Associated with Cell Necrosis Induced by Oxidant Stress?

Hepatic diseases are a major concern worldwide. Increased specific plasma enzyme activities are considered diagnostic features for liver diseases, since enzymes are released into the blood compartment following the deterioration of the organ. Release of liver mitochondrial enzymes is considered strong evidence for hepatic necrosis, which is associated with an increased production of ROS, often leading to greater hepatic lipid peroxidation. Lipotoxic mediators and intracellular signals activated Kupffer cells, which provides evidence strongly suggesting the participation of oxidant stress in acute liver damage, inducing the progression of liver injury to chronic liver damage. Elevated transaminase activities are considered as an index marker of hepatotoxicity, linked to oxidant stress. However, a drastic increase of serum activities of liver enzyme markers ought not necessarily to reflect liver cell death. In fact, increased serum levels of cytoplasmic enzymes have readily been observed after partial hepatectomy (PH) in the regenerating liver of rats. In this regard, we are now showing that in vitro modifications of the oxidant status affect differentially the release of liver enzymes, indicating that this release is a strictly controlled event and not directly related to the onset of oxidant stress of the liver.

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.