Nomenclature, diagnosis and management of drug-induced autoimmune-like hepatitis (DI-ALH): An expert opinion meeting report.

Drug-induced liver injury (DILI) can mimic almost all other liver disorders. A phenotype increasingly ascribed to drugs is autoimmune-like hepatitis (ALH). This article summarises the major topics discussed at a joint International Conference held between the Drug-Induced Liver Injury consortium and the International Autoimmune Hepatitis Group. DI-ALH is a liver injury with laboratory and/or histological features that may be indistinguishable from those of autoimmune hepatitis (AIH). Previous studies have revealed that patients with DI-ALH and those with idiopathic AIH have very similar clinical, biochemical, immunological and histological features. Differentiating DI-ALH from AIH is important as patients with DI-ALH rarely require long-term immunosuppression and the condition often resolves spontaneously after withdrawal of the implicated drug, whereas patients with AIH mostly require long-term immunosuppression. Therefore, revision of the diagnosis on long-term follow-up may be necessary in some cases. More than 40 different drugs including nitrofurantoin, methyldopa, hydralazine, minocycline, infliximab, herbal and dietary supplements (such as Khat and Tinospora cordifolia) have been implicated in DI-ALH. Understanding of DI-ALH is limited by the lack of specific markers of the disease that could allow for a precise diagnosis, while there is similarly no single feature which is diagnostic of AIH. We propose a management algorithm for patients with liver injury and an autoimmune phenotype. There is an urgent need to prospectively evaluate patients with DI-ALH systematically to enable definitive characterisation of this condition.

Secular Trends in Severe Idiosyncratic Drug-Induced Liver Injury in North America: An Update From the Acute Liver Failure Study Group Registry.

INTRODUCTION: Idiosyncratic drug-induced liver injury (DILI) is the second leading cause of acute liver failure (ALF) in the United States. Our study aims were to characterize secular trends in the implicated agents, clinical features, and outcomes of adults with DILI ALF over a 20-year period. METHODS: Among 2,332 patients with ALF enrolled in the ALF Study Group registry, 277 (11.9%) were adjudicated as idiosyncratic DILI ALF (INR ≥ 1.5 and hepatic encephalopathy) through expert opinion. The 155 cases in era 1 (January 20, 1998-January 20, 2008) were compared with the 122 cases in era 2 (January 21, 2008-January 20, 2018). RESULTS: Among 277 cases of DILI ALF, 97 different agents, alone or in combination, were implicated: antimicrobials, n = 118 (43%); herbal/dietary supplements (HDS), n = 42 (15%); central nervous system agents/illicit substances, n = 37 (13%); oncologic/biologic agents, n = 29 (10%); and other, n = 51 (18%). Significant trends over time included (i) an increase in HDS DILI ALF (9.7% vs 22%, P < 0.01) and decrease in antimicrobial-induced DILI ALF (45.8% vs. 38.5%, P = 0.03) and (ii) improved overall transplant-free survival (23.5%-38.7%, P < 0.01) while the number of patients transplanted declined (46.4% vs 33.6%, P < 0.03). DISCUSSION: DILI ALF in North America is evolving, with HDS cases rising and other categories of suspect drugs declining. The reasons for a significant increase in transplant-free survival and reduced need for liver transplantation over time remain unclear but may be due to improvements in critical care, increased NAC utilization, and improved patient prognostication.

Garcinia cambogia, Either Alone or in Combination With Green Tea, Causes Moderate to Severe Liver Injury.

BACKGROUND & AIMS: Garcinia cambogia, either alone or with green tea, is commonly promoted for weight loss. Sporadic cases of liver failure from G cambogia have been reported, but its role in liver injury is controversial. METHODS: Among 1418 patients enrolled in the Drug-Induced Liver Injury Network (DILIN) from 2004 to 2018, we identified 22 cases (adjudicated with high confidence) of liver injury from G cambogia either alone (n = 5) or in combination with green tea (n = 16) or Ashwagandha (n = 1). Control groups consisted of 57 patients with liver injury from herbal and dietary supplements (HDS) containing green tea without G cambogia and 103 patients from other HDS. RESULTS: Patients who took G cambogia were between 17 and 54 years, with liver injury arising 13-223 days (median = 51) after the start. One patient died, one required liver transplantation, and 91% were hospitalized. The liver injury was hepatocellular with jaundice. Although the peak values of aminotransferases were significantly higher (2001 ± 1386 U/L) in G cambogia group (P < .018), the median time for improvement in total bilirubin was significantly lower compared with the control groups (10 vs 17 and 13 days; P = .03). The presence of HLA-B∗35:01 allele was significantly higher in the G cambogia containing HDS (55%) compared with patients because of other HDS (19%) (P = .002) and those with acute liver injury from conventional drugs (12%) (P = 2.55 × 10-6). CONCLUSIONS: The liver injury caused by G cambogia and green tea is clinically indistinguishable. The possible association with HLA-B∗35:01 allele suggests an immune-mediated mechanism of injury. CLINICAL TRIALS: gov number: NCT00345930.

HLA-B*35:01 and Green Tea-Induced Liver Injury.

BACKGROUND AND AIMS: Herbal supplements, and particularly multi-ingredient products, have become increasingly common causes of acute liver injury. Green tea is a frequent component in implicated products, but its role in liver injury is controversial. The aim of this study was to better characterize the clinical features, outcomes, and pathogenesis of green tea-associated liver injury. APPROACH AND RESULTS: Among 1,414 patients enrolled in the U.S. Drug-Induced Liver Injury Network who underwent formal causality assessment, 40 cases (3%) were attributed to green tea, 202 to dietary supplements without green tea, and 1,142 to conventional drugs. The clinical features of green tea cases and representation of human leukocyte antigen (HLA) class I and II alleles in cases and control were analyzed in detail. Patients with green tea-associated liver injury ranged in age from 17 to 69 years (median = 40) and developed symptoms 15-448 days (median = 72) after starting the implicated agent. The liver injury was typically hepatocellular (95%) with marked serum aminotransferase elevations and only modest increases in alkaline phosphatase. Most patients were jaundiced (83%) and symptomatic (88%). The course was judged as severe in 14 patients (35%), necessitating liver transplantation in 3 (8%), but rarely resulting in chronic injury (3%). In three instances, injury recurred upon re-exposure to green tea with similar clinical features, but shorter time to onset. HLA typing revealed a high prevalence of HLA-B*35:01, found in 72% (95% confidence interval [CI], 58-87) of green tea cases, but only 15% (95% CI, 10-20) caused by other supplements and 12% (95% CI, 10-14) attributed to drugs, the latter rate being similar to population controls (11%; 95% CI, 10.5-11.5). CONCLUSIONS: Green tea-related liver injury has distinctive clinical features and close association with HLA-B*35:01, suggesting that it is idiosyncratic and immune mediated.

Severe and protracted cholestasis in 44 young men taking bodybuilding supplements: assessment of genetic, clinical and chemical risk factors.

BACKGROUND: Bodybuilding supplements can cause a profound cholestatic syndrome. AIM: To describe the drug-Induced liver injury network's experience with liver injury due to bodybuilding supplements. METHODS: Liver injury pattern, severity and outcomes, potential genetic associations, and exposure to anabolic steroids by product analysis were analysed in prospectively enrolled subjects with bodybuilding supplement-induced liver injury with causality scores of probable or higher. RESULTS: Forty-four males (mean age 33 years) developed liver injury with a median latency of 73 days. Forty-one per cent presented with hepatocellular pattern of liver injury as defined by the R > 5 ([Fold elevation of ALT] ÷ [Fold elevation of Alk Phos] (mean, range = 6.4, 0.5-31.4, n = 42) despite all presenting with clinical features of cholestatic liver injury (100% with jaundice and 84% with pruritus). Liver biopsy (59% of subjects) demonstrated a mild hepatitis and profound cholestasis in most without bile duct injury, loss or fibrosis. Seventy-one per cent were hospitalised, and none died or required liver transplantation. In some, chemical analysis revealed anabolic steroid controlled substances not listed on the label. No enrichment of genetic variants associated with cholestatic syndromes was found, although mutations in ABCB11 (present in up to 20%) were significantly different than in ethnically matched controls. CONCLUSIONS: Patients with bodybuilding supplements liver injury uniformly presented with cholestatic injury, which slowly resolved. The ingested products often contained anabolic steroids not identified on the label, and no enrichment in genetic variants was found, indicating a need for additional studies.

The diagnosis and management of idiosyncratic drug-induced liver injury.

Drug-induced liver injury (DILI) is an uncommon but important cause of liver disease that can arise after exposure to a multitude of drugs and herbal and dietary supplements. The severity of idiosyncratic DILI varies from mild serum aminotransferase elevations to the development of severe liver injury that can progress to acute liver failure resulting in death or liver transplantation within days of DILI onset. Chronic liver injury that persists for more than 6 months after DILI onset is also becoming increasingly recognized in up to 20% of DILI patients. Host demographic (age, gender, race), clinical and laboratory features at DILI onset have been associated with the severity and outcome of liver injury in DILI patients. In addition to cessation of the suspect drug, other medical interventions including the use of N-acetylcysteine and corticosteroids in selected patients have shown some clinical benefit, but additional prospective studies are needed. A number of promising diagnostic, prognostic and mechanistic serum and genetic biomarkers may help improve our understanding of the pathogenesis and treatment of idiosyncratic DILI.

Liver Injury Associated with Sporting Activities.

Exertional heat stroke most commonly develops following prolonged levels of aerobic activity in a warm or humid environment. Hypoperfusion of the vital organs along with activation of the inflammasome can lead to progressive and potentially fatal multiorgan failure including acute liver failure. In the United States, herbal and dietary supplements that are marketed to improve performance, strength, and weight loss are increasingly being used by both amateur and professional athletes. Consumption of bodybuilding supplements that contain androgenic anabolic steroids can lead to adverse hepatic effects ranging from asymptomatic serum aminotransferase elevations to severe cholestatic hepatitis with prolonged jaundice. Various non-bodybuilding nutritional supplements that contain a mixture of botanicals, caffeine, and chemicals have also been associated with idiosyncratic hepatotoxicity. In particular, green tea extract derivatives that contain epigallocatechin gallate are hepatotoxic in animal models and have been associated with severe acute hepatocellular injury in humans.

Safety, tolerability, and pharmacokinetics of l-ornithine phenylacetate in patients with acute liver injury/failure and hyperammonemia.

Cerebral edema remains a significant cause of morbidity and mortality in patients with acute liver failure (ALF) and has been linked to elevated blood ammonia levels. l-ornithine phenylacetate (OPA) may decrease ammonia by promoting its renal excretion as phenylacetylglutamine (PAGN), decreasing the risk of cerebral edema. We evaluated the safety, tolerability, and pharmacokinetics of OPA in patients with ALF and acute liver injury (ALI), including those with renal failure. Forty-seven patients with ALI/ALF and ammonia ≥60 µM were enrolled. Patients received OPA in a dose escalation scheme from 3.3 g every 24 hours to 10 g every 24 hours; 15 patients received 20 g every 24 hours throughout the infusion for up to 120 hours. Plasma phenylacetate (PA) concentrations were uniformly below target (<75 µg/mL) in those receiving 3.3 g every 24 hours (median [interquartile range] 5.0 [5.0] µg/mL), and increased to target levels in all but one who received 20 g every 24 hours (150 [100] µg/mL). Plasma [PAGN] increased, and conversion of PA to PAGN became saturated, with increasing OPA dose. Urinary PAGN clearance and creatinine clearance were linearly related (r = 0.831, P < 0.0001). Mean ammonia concentrations based on the area under the curve decreased to a greater extent in patients who received 20 g of OPA every 24 hours compared with those who received the maximal dose of 3.3 or 6.7 g every 24 hours (P = 0.046 and 0.022, respectively). Of the reported serious adverse events (AEs), which included 11 deaths, none was attributable to study medication. The only nonserious AEs possibly related to study drug were headache and nausea/vomiting. CONCLUSION: OPA was well-tolerated in patients with ALI/ALF, and no safety signals were identified. Target [PA] was achieved at infusion rates of 20 g every 24 hours, leading to ammonia excretion in urine as PAGN in proportion to renal function. Randomized, controlled studies of high-dose OPA are needed to determine its use as an ammonia-scavenging agent in patients with ALF. (Hepatology 2018;67:1003-1013).

Clinical presentations and outcomes of bile duct loss caused by drugs and herbal and dietary supplements.

Bile duct loss during the course of drug-induced liver injury is uncommon, but can be an indication of vanishing bile duct syndrome (VBDS). In this work, we assess the frequency, causes, clinical features, and outcomes of cases of drug-induced liver injury with histologically proven bile duct loss. All cases of drug-induced liver injury enrolled into a prospective database over a 10-year period that had undergone liver biopsies (n = 363) were scored for the presence of bile duct loss and assessed for clinical and laboratory features, causes, and outcomes. Twenty-six of the 363 patients (7%) with drug-, herbal-, or dietary-supplement-associated liver injury had bile duct loss on liver biopsy, which was moderate to severe (<50% of portal areas with bile ducts) in 14 and mild (50%-75%) in 12. The presenting clinical features of the 26 cases varied, but the most common clinical pattern was a severe cholestatic hepatitis. The implicated agents included amoxicillin/clavulanate (n = 3), temozolomide (n = 3), various herbal products (n = 3), azithromycin (n = 2), and 15 other medications or dietary supplements. Compared to those without, those with bile duct loss were more likely to develop chronic liver injury (94% vs. 47%), which was usually cholestatic and sometimes severe. Five patients died and 2 others underwent liver transplantation for progressive cholestasis despite treatment with corticosteroids and ursodiol. The most predictive factor of poor outcome was the degree of bile duct loss on liver biopsy. CONCLUSION: Bile duct loss during acute cholestatic hepatitis is an ominous early indicator of possible VBDS, for which at present there are no known means of prevention or therapy. (Hepatology 2017;65:1267-1277).

Risk of Liver Injury Associated with Green Tea Extract in SLIMQUICK(®) Weight Loss Products: Results from the DILIN Prospective Study.

INTRODUCTION: Herbal and dietary supplements (HDS) have been increasingly recognized as a cause for acute liver injury (Navarro et al. Hepatology 60(4):1399-1408, 2014; Bailey et al. J Nutr 141:261-266, 2011). HDS products frequently contain numerous ingredients, and are marketed under various product names. A perusal of marketed weight loss products indicates that green tea extract (GTE) is a common ingredient in many. We aimed to describe the course and outcome of six patients who developed liver injury attributed to SLIMQUICK(®) weight loss products. METHODS: Patients with suspected drug-induced liver injury were enrolled in a prospective study of the Drug-Induced Liver Injury Network (DILIN) and causality was assessed by a panel of hepatologists. During the period under study, 6 of 1091 cases of liver injury were attributed to a SLIMQUICK(®) product and were assigned causality scores of probable, highly likely, or definite. RESULTS: Six cases of acute liver injury attributed to SLIMQUICK(®) products were enrolled in the DILIN prospective study between 2007 and 2011. All were women aged 22 to 58 years. Two had a normal body weight and four were mildly obese (body mass index 22.9-32.2 kg/m(2)). All were taking SLIMQUICK(®) products for weight loss and no patient reported prior use. Laboratory tests revealed a hepatocellular pattern of injury, with initial alanine aminotransferase (ALT) levels above 1000 U/L in all but one patient. Three patients were hospitalized and one underwent successful liver transplantation. No patients died of liver injury. GTE and/or its component catechins were listed among the ingredients for five of the six products. CONCLUSIONS: SLIMQUICK(®) products can lead to severe acute hepatocellular liver injury, which may result in transplantation. Given the frequency of GTE as a component in weight loss products, this ingredient should be studied further as a possible cause for liver injury.

Severe Acute Hepatocellular Injury Attributed to OxyELITE Pro: A Case Series.

BACKGROUND/AIM: Herbal and dietary supplement (HDS) hepatotoxicity is increasingly being reported in the USA. This case series describes the presenting clinical features and outcomes of seven patients with liver injury attributed to OxyELITE Pro enrolled in the Drug-Induced Liver Injury Network (DILIN) study. METHODS: The 6-month outcomes of patients with hepatotoxicity attributed to OxyELITE Pro enrolled in the DILIN prospective registry between 2004 and 2015 are presented. RESULTS: Six of the seven patients (86 %) presented in 2013 with symptoms of hepatitis and acute hepatocellular injury. The median duration of OxyELITE Pro use was 18 weeks (range 5-102 weeks). Median age was 36 years (range 28-62), 86 % were female, and 43 % were Asian. One patient had rash, none had eosinophilia, and three had antinuclear antibody reactivity. The median peak ALT was 2242 U/L, alkaline phosphatase 284 U/L and bilirubin 15.0 mg/dL. Six patients (86 %) were hospitalized, three developed acute liver failure and two underwent liver transplantation. DILIN causality scores for OxyELITE Pro were definite in 1, highly likely in 3, probable in 2, and possible in 1. Four of the five patients without liver transplant recovered completely within 6 months, while one patient had mild residual ALT elevations. CONCLUSIONS: Seven cases of severe acute hepatocellular injury attributed to OxyELITE Pro are reported. These results reinforce the need to assess for HDS supplement use in patients presenting with unexplained acute hepatitis and point to the need for additional regulatory oversight of HDS products.

Reliability of causality assessment for drug, herbal and dietary supplement hepatotoxicity in the Drug-Induced Liver Injury Network (DILIN).

BACKGROUND & AIMS: Because of the lack of objective tests to diagnose drug-induced liver injury (DILI), causality assessment is a matter of debate. Expert opinion is often used in research and industry, but its test-retest reliability is unknown. To determine the test-retest reliability of the expert opinion process used by the Drug-Induced Liver Injury Network (DILIN). METHODS: Three DILIN hepatologists adjudicate suspected hepatotoxicity cases to one of five categories representing levels of likelihood of DILI. Adjudication is based on retrospective assessment of gathered case data that include prospective follow-up information. One hundred randomly selected DILIN cases were re-assessed using the same processes for initial assessment but by three different reviewers in 92% of cases. RESULTS: The median time between assessments was 938 days (range 140-2352). Thirty-one cases involved >1 agent. Weighted kappa statistics for overall case and individual agent category agreement were 0.60 (95% CI: 0.50-0.71) and 0.60 (0.52-0.68) respectively. Overall case adjudications were within one category of each other 93% of the time, while 5% differed by two categories and 2% differed by three categories. Fourteen per cent crossed the 50% threshold of likelihood owing to competing diagnoses or atypical timing between drug exposure and injury. CONCLUSIONS: The DILIN expert opinion causality assessment method has moderate interobserver reliability but very good agreement within one category. A small but important proportion of cases could not be reliably diagnosed as ≥50% likely to be DILI.

Liver injury from herbals and dietary supplements in the U.S. Drug-Induced Liver Injury Network.

UNLABELLED: The Drug-Induced Liver Injury Network (DILIN) studies hepatotoxicity caused by conventional medications as well as herbals and dietary supplements (HDS). To characterize hepatotoxicity and its outcomes from HDS versus medications, patients with hepatotoxicity attributed to medications or HDS were enrolled prospectively between 2004 and 2013. The study took place among eight U.S. referral centers that are part of the DILIN. Consecutive patients with liver injury referred to a DILIN center were eligible. The final sample comprised 130 (15.5%) of all subjects enrolled (839) who were judged to have experienced liver injury caused by HDS. Hepatotoxicity caused by HDS was evaluated by expert opinion. Demographic and clinical characteristics and outcome assessments, including death and liver transplantation (LT), were ascertained. Cases were stratified and compared according to the type of agent implicated in liver injury; 45 had injury caused by bodybuilding HDS, 85 by nonbodybuilding HDS, and 709 by medications. Liver injury caused by HDS increased from 7% to 20% (P < 0.001) during the study period. Bodybuilding HDS caused prolonged jaundice (median, 91 days) in young men, but did not result in any fatalities or LT. The remaining HDS cases presented as hepatocellular injury, predominantly in middle-aged women, and, more frequently, led to death or transplantation, compared to injury from medications (13% vs. 3%; P < 0.05). CONCLUSIONS: The proportion of liver injury cases attributed to HDS in DILIN has increased significantly. Liver injury from nonbodybuilding HDS is more severe than from bodybuilding HDS or medications, as evidenced by differences in unfavorable outcomes (death and transplantation). (Hepatology 2014;60:1399-1408).

ACG Clinical Guideline: the diagnosis and management of idiosyncratic drug-induced liver injury.

Idiosyncratic drug-induced liver injury (DILI) is a rare adverse drug reaction and it can lead to jaundice, liver failure, or even death. Antimicrobials and herbal and dietary supplements are among the most common therapeutic classes to cause DILI in the Western world. DILI is a diagnosis of exclusion and thus careful history taking and thorough work-up for competing etiologies are essential for its timely diagnosis. In this ACG Clinical Guideline, the authors present an evidence-based approach to diagnosis and management of DILI with special emphasis on DILI due to herbal and dietary supplements and DILI occurring in individuals with underlying liver disease.

Polymerase γ gene POLG determines the risk of sodium valproate-induced liver toxicity.

UNLABELLED: Sodium valproate (VPA) is widely used throughout the world to treat epilepsy, migraine, chronic headache, bipolar disorder, and as adjuvant chemotherapy. VPA toxicity is an uncommon but potentially fatal cause of idiosyncratic liver injury. Rare mutations in POLG, which codes for the mitochondrial DNA polymerase γ (polγ), cause Alpers-Huttenlocher syndrome (AHS). AHS is a neurometabolic disorder associated with an increased risk of developing fatal VPA hepatotoxicity. We therefore set out to determine whether common genetic variants in POLG explain why some otherwise healthy individuals develop VPA hepatotoxicity. We carried out a prospective study of subjects enrolled in the Drug Induced Liver Injury Network (DILIN) from 2004 to 2008 through five US centers. POLG was sequenced and the functional consequences of VPA and novel POLG variants were evaluated in primary human cell lines and the yeast model system Saccharomyces cerevisiae. Heterozygous genetic variation in POLG was strongly associated with VPA-induced liver toxicity (odds ratio = 23.6, 95% confidence interval [CI] = 8.4-65.8, P = 5.1 × 10⁻7). This was principally due to the p.Q1236H substitution which compromised polγ function in yeast. Therapeutic doses of VPA inhibited human cellular proliferation and high doses caused nonapoptotic cell death, which was not mediated through mitochondrial DNA depletion, mutation, or a defect of fatty acid metabolism. CONCLUSION: These findings implicate impaired liver regeneration in VPA toxicity and show that prospective genetic testing of POLG will identify individuals at high risk of this potentially fatal consequence of treatment.

Standardization of nomenclature and causality assessment in drug-induced liver injury: summary of a clinical research workshop.

UNLABELLED: Idiosyncratic drug-induced liver injury (DILI) is an important but relatively infrequent cause of potentially severe acute and chronic liver injury. The aim of this clinical research workshop was to review and attempt to standardize the current nomenclature and terminology used in DILI research. Because DILI is a diagnosis of exclusion, selected elements of the medical history, laboratory tests, and previous reports were proposed to improve causality assessment. Definitions and diagnostic criteria regarding the onset of DILI, evolution of liver injury, risk factors, and mandatory testing versus optional testing for competing causes were reviewed. In addition, the role of intentional and inadvertent rechallenge, liver histology, and host genetic polymorphisms in establishing the diagnosis and prognosis of DILI were reviewed. Consensus was established regarding the need to develop a web-of-knowledge database that provides concise, reliable, and updated information on cases of liver injury due to drugs and herbal and dietary supplements. In addition, the need to develop drug-specific computerized causality assessment methods that are derived from prospectively phenotyped cases was a high priority. Proposed scales for grading DILI severity and assessing the likelihood of an agent causing DILI and written criteria for improving the reliability, accuracy, and reproducibility of expert opinion were reviewed. Finally, the unique challenges of assessing causality in children, patients with underlying liver disease, and subjects taking herbal and dietary supplements were discussed. CONCLUSION: Workshop participants concluded that multicenter referral networks enrolling patients with suspected DILI according to standardized methodologies are needed. These networks should also collect biological samples that may provide crucial insights into the mechanism(s) of DILI with the ultimate aim of preventing future cases of DILI.

Causes, clinical features, and outcomes from a prospective study of drug-induced liver injury in the United States.

BACKGROUND & AIMS: Idiosyncratic drug-induced liver injury (DILI) is among the most common causes of acute liver failure in the United States, accounting for approximately 13% of cases. A prospective study was begun in 2003 to recruit patients with suspected DILI and create a repository of biological samples for analysis. This report summarizes the causes, clinical features, and outcomes from the first 300 patients enrolled. METHODS: Patients with suspected DILI were enrolled based on predefined criteria and followed up for at least 6 months. Patients with acetaminophen liver injury were excluded. RESULTS: DILI was caused by a single prescription medication in 73% of the cases, by dietary supplements in 9%, and by multiple agents in 18%. More than 100 different agents were associated with DILI; antimicrobials (45.5%) and central nervous system agents (15%) were the most common. Causality was considered to be definite in 32%, highly likely in 41%, probable in 14%, possible in 10%, and unlikely in 3%. Acute hepatitis C virus (HCV) infection was the final diagnosis in 4 of 9 unlikely cases. Six months after enrollment, 14% of patients had persistent laboratory abnormalities and 8% had died; the cause of death was liver related in 44%. CONCLUSIONS: DILI is caused by a wide array of medications, herbal supplements, and dietary supplements. Antibiotics are the single largest class of agents that cause DILI. Acute HCV infection should be excluded in patients with suspected DILI by HCV RNA testing. The overall 6-month mortality was 8%, but the majority of deaths were not liver related.