Hepatotoxicity during rapid intravenous loading with amiodarone: Description of three cases and review of the literature

Acute hepatotoxicity of intravenous amiodarone in a Becker muscular dystrophy patient with decompensated heart failing and ABCB4 gene mutation: as assessed for causality using the updated RUCAM

BACKGROUND

Cardiac dysfunction, including arrhythmias, may be one of the main clinical manifestations of Becker muscular dystrophy (BMD). Amiodarone is widely used to treat arrhythmia. However, multi-systemic toxicity caused by amiodarone, especially hepatotoxicity, should not be neglected. Here, we introduce a novel case of multi-systemic amiodarone toxicity involving the liver, renal and coagulation in BDM patient with ABCB4 gene mutation.

CASE PRESENTATION

We present a case of a 16-year-old boy admitted with heart failure and atrial fibrillation (AF). He was diagnosed with Becker muscular dystrophy (BMD) and gene testing showed comorbid mutations in gene DMD, ABCB4 and DSC2. Amiodarone was prescribed to control the paroxysmal atrial fibrillation intravenously. However, his liver enzyme levels were sharply elevated, along with cardiac shock, renal failure and coagulation disorders. After bedside continuous renal replacement therapy, the patient's liver function and clinical status rehabilitated.

CONCLUSIONS

ABCB4 gene mutation might be involved in amiodarone-induced hepatotoxicity. Studies in a cohort might help to prove this hypothesis in the future.

Review article: Hepatic steatosis and its associations with acute and chronic liver diseases

BACKGROUND

Hepatic steatosis is a common finding in liver histopathology and the hallmark of metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), whose global prevalence is rising.

AIMS

To review the histopathology of hepatic steatosis and its mechanisms of development and to identify common and rare disease associations.

METHODS

We reviewed literature on the basic science of lipid droplet (LD) biology and clinical research on acute and chronic liver diseases associated with hepatic steatosis using the PubMed database.

RESULTS

A variety of genetic and environmental factors contribute to the development of chronic hepatic steatosis or steatotic liver disease, which typically appears macrovesicular. Microvesicular steatosis is associated with acute mitochondrial dysfunction and liver failure. Fat metabolic processes in hepatocytes whose dysregulation leads to the development of steatosis include secretion of lipoprotein particles, uptake of remnant lipoprotein particles or free fatty acids from blood, de novo lipogenesis, oxidation of fatty acids, lipolysis and lipophagy. Hepatic insulin resistance is a key feature of MASLD. Seipin is a polyfunctional protein that facilitates LD biogenesis. Assembly of hepatitis C virus takes place on LD surfaces. LDs make important, functional contact with the endoplasmic reticulum and other organelles.

CONCLUSIONS

Diverse liver pathologies are associated with hepatic steatosis, with MASLD being the most important contributor. The biogenesis and dynamics of LDs in hepatocytes are complex and warrant further investigation. Organellar interfaces permit co-regulation of lipid metabolism to match generation of potentially toxic lipid species with their LD depot storage.

Liver failure caused by intravenous amiodarone and effective intervention measures: A case report

WHAT IS KNOWN AND OBJECTIVE

We present a case of intravenous amiodarone-induced liver injury, pharmacy monitoring and its therapy.

CASE SUMMARY

A 76-year-old male patient developed acute liver injury 24 h after starting intravenous amiodarone. His liver enzymes improved after discontinuing amiodarone and anti-inflammatory liver therapy, which used reduced glutathione, magnesium isoglycyrrhizinate and ademetionine1,4-butanedisulfonate for injection.

WHAT IS NEW AND CONCLUSION

Amiodarone is a highly effective antiarrhythmic agent for the treatment and prevention of atrial and ventricular arrhythmias. Acute liver damage after intravenous amiodarone is rare but potentially harmful. Amiodarone loading should be adapted to the necessity of an immediate effect of the drug, and liver function should be monitored closely in critically ill patients. Timely stopped suspected drug and anti-inflammatory liver therapy may reduce the occurrence of drug-induced diseases.

Emerging club drugs: 5-(2-aminopropyl)benzofuran (5-APB) is more toxic than its isomer 6-(2-aminopropyl)benzofuran (6-APB) in hepatocyte cellular models

New phenylethylamine derivatives are among the most commonly abused new psychoactive substances. They are synthesized and marketed in lieu of classical amphetaminic stimulants, with no previous safety testing. Our study aimed to determine the in vitro hepatotoxicity of two benzofurans [6-(2-aminopropyl)benzofuran (6-APB) and 5-(2-aminopropyl)benzofuran (5-APB)] that have been misused as 'legal highs'. Cellular viability was assessed through the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay, following 24-h drug exposure of human hepatoma HepaRG cells (EC₅₀ 2.62 mM 5-APB; 6.02 mM 6-APB), HepG2 cells (EC₅₀ 3.79 mM 5-APB; 8.18 mM 6-APB) and primary rat hepatocytes (EC₅₀ 964 μM 5-APB; 1.94 mM 6-APB). Co-incubation of primary hepatocytes, the most sensitive in vitro model, with CYP450 inhibitors revealed a role of metabolism, in particular by CYP3A4, in the toxic effects of both benzofurans. Also, 6-APB and 5-APB concentration-dependently enhanced oxidative stress (significantly increased reactive species and oxidized glutathione, and decreased reduced glutathione levels) and unsettled mitochondrial homeostasis, with disruption of mitochondrial membrane potential and decline of intracellular ATP. Evaluation of cell death mechanisms showed increased caspase-8, -9, and -3 activation, and nuclear morphological changes consistent with apoptosis; at concentrations higher than 2 mM, however, necrosis prevailed. Concentration-dependent formation of acidic vesicular organelles typical of autophagy was also observed for both drugs. Overall, 5-APB displayed higher hepatotoxicity than its 6-isomer. Our findings provide new insights into the potential hepatotoxicity of these so-called 'safe drugs' and highlight the putative risks associated with their use as psychostimulants.

Hyperammonemic Encephalopathy and Lipid Dysmetabolism in a Critically Ill Patient After a Short Course of Amiodarone

The case is reported of a 39-year-old severely obese woman who developed acute metabolic disorders after the administration of a short course of intravenous amiodarone. The main biological features were hypertriglyceridemia, hypoglycaemia, hyperlactatemia and hyperammonemia; all were reversible after amiodarone discontinuation. There was an associated rise in liver enzymes. However, the influence of co-factors on these metabolic disorders, such as acquired carnitine deficiency, severe obesity, a long-term course of pancreatitis, and abdominal infections, could not be excluded.

Efficacy and safety of 1C class antiarrhythmic agent (propafenone) for supraventricular arrhythmias in septic shock compared to amiodarone: protocol of a prospective randomised double-blind study

INTRODUCTION

Supraventricular arrhythmias contribute to haemodynamic compromise in septic shock. A retrospective study generated the hypothesis that propafenone could be more effective than amiodarone in achieving and maintaining sinus rhythm (SR). Certain echocardiographic parameters may predict a successful cardioversion and help in the decision on rhythm or rate control strategy.

METHODS AND ANALYSIS

The trial includes septic shock patients with new-onset arrhythmia, but without severe impairment of the left ventricular ejection fraction. After baseline echocardiography, the patient is randomised to receive a bolus and maintenance dose of either amiodarone or propafenone. The primary outcome is the proportion of patients that have achieved rhythm control at 24 hours after the start of the infusion. The secondary outcomes are the percentages of patients that needed rescue treatments (DC cardioversion or unblinding and crossover of the antiarrhythmics), the recurrence of arrhythmias, intensive care unit mortality, 28-day and 1-year mortality. In the posthoc analysis, we separately assess subgroups of patients with pulmonary hypertension and right ventricular dysfunction. In the exploratory part of the study, we assess whether the presence of a transmitral diastolic A wave and its higher velocity-time integral is predictive for the sustainability of mechanical SR and whether the indexed left atrial endsystolic volume is predictive of recurrent arrhythmia. Considering that the restoration of SR within 24 hours occurred in 74% of the amiodarone-treated patients and in 89% of the patients treated with propafenone, we plan to include 200 patients to have an 80% chance to demonstrate the superiority of propafenone at p=0.05.

ETHICS AND DISSEMINATION

The trial is recruiting patients according to its second protocol version approved by the University Hospital Ethical Board on the 6 October 2017 (No. 1691/16S-IV). The results will be disseminated through peer reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

NCT03029169.

Comedication with interacting drugs predisposes amiodarone users in cardiac and surgical intensive care units to acute liver injury: A retrospective analysis

Risk factors and underlying mechanisms for liver injury associated with amiodarone remain elusive. This study aimed to investigate the drug-related covariates for acute liver injury by amiodarone-an intriguing compound of high lipophilicity, with a long half-life and notable efficacy.The medical, pharmacy, and laboratory records of new amiodarone users admitted to the cardiac or surgical intensive care units of a medical center were examined retrospectively. A Cox regression model with time-varying dose-related variables of amiodarone was utilized to estimate the hazard ratio (HR) of amiodarone-associated liver injury while adjusting for concomitant therapy and relevant covariates.Of the 131 eligible patients among 6,572 amiodarone users (46,402 prescriptions), 6 were identified as amiodarone-associated liver injury cases. In comparison to controls (n = 125), this liver injury cohort (n = 6) had significantly higher numbers of amiodarone-interacting (2.7 ± 2.0 vs 0.9 ± 0.9 drugs, P = .02) and hepatotoxic (3.8 ± 0.8 vs 2.5 ± 1.7 drugs, P = .03) comedications. The number of comedications with amiodarone-interacting potential (HR 2.07, 95% confidence interval [CI] 1.02-4.22, P = .04) and amiodarone cumulative doses standardized by body surface area (HR 6.82, 95% CI 1.72-27.04, P = .01) were independent risk factors for liver injury associated with amiodarone.Drug-related (amiodarone cumulative dose, interacting drugs) factors were significant predictors of amiodarone-associated acute liver injury. A prudent evaluation of each medication profile is warranted to attain precision medicine at the level of patient care, especially for those treated by medications with complex physicochemical and pharmacokinetic properties, such as amiodarone.

Acute liver failure with amiodarone infusion: A case report and systematic review

WHAT IS KNOWN AND OBJECTIVE

Amiodarone, a commonly used class III antiarrhythmic agent notable for a relatively long half-life of up to 6 months and its pronounced adverse effect profile, is used for both acute and chronic management of cardiac arrhythmias. Chronic use of amiodarone has been associated with asymptomatic hepatotoxicity; however, acute toxicity is thought to be uncommon. There are only six reported cases of acute liver failure (ALF) secondary to amiodarone. In all these cases the outcome of death during the same hospitalization resulted. We aimed to report the only case of acute liver failure secondary to amiodarone infusion in the existing literature where the patient survived.

CASE SUMMARY

A 79-year-old woman admitted with atrial flutter was being treated with intravenous (IV) amiodarone when she abruptly developed coagulopathy, altered mental status and liver enzyme derangement. She was diagnosed with acute liver failure (ALF) secondary to an amiodarone adverse drug reaction, with a calculated score of seven on the Naranjo adverse drug reaction probability scale. Amiodarone was immediately withheld, and N-acetylcysteine (NAC) was initiated. Clinical improvement was seen within 48 hours of holding the drug and within 24 hours of initiating NAC. On post-hospital follow-up visit she was reported to have complete recovery.

WHAT IS NEW AND CONCLUSION

This report emphasizes the importance of monitoring liver enzymes and mental status while a patient is being administered IV amiodarone. N-acetylcysteine administration may have possibly contributed to the early and successful recovery from ALF in our patient. To date, she is the only patient in the existing literature who has been reported to survive ALF secondary to amiodarone administration.

Modeling of Amiodarone Effect on Heart Rate Control in Critically Ill Patients with Atrial Tachyarrhythmias

AIMS

Amiodarone is the gold-standard medication to control heart rate in critically ill patients with atrial tachyarrhythmias (ATs); however, effective doses and covariates influencing its efficacy remain unknown. We therefore performed pharmacodynamic modeling of heart rate reduction induced by amiodarone in these patients.

METHODS AND RESULTS

This observational study included 80 consecutive severely ill patients receiving amiodarone to treat ATs. A total of 1348 time-heart rate observations with 361 amiodarone dose administrations were analyzed during a period of up to 6 days after hospital treatment initiation using a nonlinear mixed-effect model. Pretreatment with amiodarone before intensive care administration, paroxysmal versus persistent AT, catecholamine infusion, and fluid and magnesium loading were among the covariates assessed in the model. In case of paroxysmal AT in a patient not pretreated with amiodarone, a 300 mg intravenous loading dose combined with an 800 mg oral dose on the first day, followed by 800 mg/day orally for 4 days was effective in achieving a heart rate between 80 and 115 bpm within the first day, and to maintain it during the next 4 days. Corresponding doses were twice as high in patients with persistent AT. Use of intravenous magnesium (p < 0.02) and fluid loading (p < 0.02) was associated with an earlier and greater heart rate decrease, while use of dobutamine had an opposite influence (p < 0.05).

CONCLUSIONS

In critically ill patients with AT, the dose of amiodarone required to control heart rate is influenced by the type of AT and by other easily measurable conditions which may allow better individualization of amiodarone dosing.

Evidence-based selection of training compounds for use in the mechanism-based integrated prediction of drug-induced liver injury in man

The current test systems employed by pharmaceutical industry are poorly predictive for drug-induced liver injury (DILI). The ‘MIP-DILI’ project addresses this situation by the development of innovative preclinical test systems which are both mechanism-based and of physiological, pharmacological and pathological relevance to DILI in humans. An iterative, tiered approach with respect to test compounds, test systems, bioanalysis and systems analysis is adopted to evaluate existing models and develop new models that can provide validated test systems with respect to the prediction of specific forms of DILI and further elucidation of mechanisms. An essential component of this effort is the choice of compound training set that will be used to inform refinement and/or development of new model systems that allow prediction based on knowledge of mechanisms, in a tiered fashion. In this review, we focus on the selection of MIP-DILI training compounds for mechanism-based evaluation of non-clinical prediction of DILI. The selected compounds address both hepatocellular and cholestatic DILI patterns in man, covering a broad range of pharmacologies and chemistries, and taking into account available data on potential DILI mechanisms (e.g. mitochondrial injury, reactive metabolites, biliary transport inhibition, and immune responses). Known mechanisms by which these compounds are believed to cause liver injury have been described, where many if not all drugs in this review appear to exhibit multiple toxicological mechanisms. Thus, the training compounds selection offered a valuable tool to profile DILI mechanisms and to interrogate existing and novel in vitro systems for the prediction of human DILI.

Acute Liver and Renal Failure: A Rare Adverse Effect Exclusive to Intravenous form of Amiodarone

Amiodarone is an antiarrhythmic drug which is highly effective against a wide spectrum of ventricular tachyarrhythmias making it irreplaceable in certain group of patients. We report an unusual case of acute liver and renal failure within 24 hours of initiation of intravenous (IV) amiodarone which resolved after stopping the medication. The mechanism of acute liver and renal toxicity is not clearly known but is believed to be secondary to amiodarone induced (relative) hypotension, idiosyncratic reaction to the drug, and toxicity of the vector that carries the medication, polysorbate-80. In this case review, we discuss the hyperacute drug toxicity caused by IV amiodarone being a distinctly different entity compared to the adverse effects shown by oral amiodarone and support the suggestion that oral amiodarone can be safely administered even in patients who manifest acute hepatitis with the IV form.

Hepatic Dysfunction in Patients Receiving Intravenous Amiodarone

OBJECTIVES

Amiodarone is a commonly used antiarrhythmic drug. Hepatotoxicity following chronic oral administration occurs in 1% to 3% of patients. Hepatotoxicity following intravenous (IV) administration is infrequent but may be associated with dramatic increases in serum transaminases. We describe the incidence of liver toxicity among patients receiving IV amiodarone during a 5-year period.

METHODS

This was a single-center retrospective review of patients receiving IV amiodarone for any cause. The outcome measures were development of elevated serum transaminases and the relation of transaminitis to all-cause 30-day mortality.

RESULTS

A total of 1510 patients received amiodarone intravenously between 2005 and 2011; 77 (5%) developed elevated liver enzymes. Enzyme elevation was divided into mild (100-300 IU/L), moderate (300-1000 IU/L), and severe (>1000 IU/L). The median alanine aminotransferase was 189 (37-10,006) IU/L and aspartate aminotransferase was 253 (84-12,005) IU/L. The 30-day mortality among those with transaminitis was 22%; however, no patient died of amiodarone-related liver disease.

CONCLUSIONS

Amiodarone can cause severe elevation in liver enzymes. The incidence of severe transaminitis is low; deaths following IV amiodarone are rarely caused by drug-induced liver failure.

Predictors of intravenous amiodarone induced liver injury

Background

Intravenous (IV) amiodarone may be associated with liver injury that may necessitate drug discontinuation. The prediction of amiodarone induced liver injury (AILI) and its severity may help careful patient monitoring or the choice of other measures alternative to amiodarone in high risk patients. Little is known regarding predictors of AILI.

Objectives

To address the predictors of AILI and its severity.

Methods

The study included 180 patients indicated for IV amiodarone therapy who were divided into 2 groups: cases (90 patients) who developed AILI, and controls (90 patients) who did not develop AILI. AILI was defined as aminotransferase (ALT and AST) elevation by ⩾2 folds of baseline levels. Severe AILI was defined as enzyme elevation by >5 folds of baseline values.

Results

Multivariate analysis showed that the presence of cardiomyopathy (P = 0.032), congestive hepatomegaly (P = 0.001), increasing baseline total bilirubin (P < 0.0001), direct current cardioversion (P = 0.015), and increasing dose of amiodarone (P = 0.014) to be independent predictors for AILI. Regarding severity of AILI, inotropic support (P = 0.034), congestive hepatomegaly (P = 0.012), increasing baseline total bilirubin (P = 0.001), and increasing dose of amiodarone (P = 0.002) were found to be independent predictors for severe AILI. Among cases, linear regression analysis showed that baseline ALT was the only significant independent predictor of post-amiodarone ALT (P < 0.0001), while baseline AST (P < 0.0001) and EF (P = 0.012) were the only significant independent predictors of post-amiodarone AST.

Conclusions

Compromised cardiac, hepatic, and hemodynamic conditions, with increasing dose of IV amiodarone were associated with AILI. Severity of liver injury had linear relationship with baseline aminotransferase levels and left ventricular systolic function.

Development of HepG2-derived cells expressing cytochrome P450s for assessing metabolism-associated drug-induced liver toxicity

The generation of reactive metabolites from therapeutic agents is one of the major mechanisms of drug-induced liver injury (DILI). In order to evaluate metabolism-related toxicity and improve drug efficacy and safety, we generated a battery of HepG2-derived cell lines that express 14 cytochrome P450s (CYPs) (1A1, 1A2, 1B1, 2A6, 2B6, 2C8, 2C9, 2C18, 2C19, 2D6, 2E1, 3A4, 3A5 and 3A7) individually using a lentiviral expression system. The expression/production of a specific CYP in each cell line was confirmed by an increased abundance of the CYP at both mRNA and protein levels. Moreover, the enzymatic activities of representative CYPs in the corresponding cell lines were also measured. Using our CYP-expressed HepG2 cells, the toxicity of three drugs that could induce DILI (amiodarone, chlorpromazine and primaquine) was assessed, and all of them showed altered (increased or decreased) toxicity compared to the toxicity in drug-treated wild-type HepG2 cells. CYP-mediated drug toxicity examined in our cell system is consistent with previous reports, demonstrating the potential of these cells for assessing metabolism-related drug toxicity. This cell system provides a practical in vitro approach for drug metabolism screening and for early detection of drug toxicity. It is also a surrogate enzyme source for the enzymatic characterization of a particular CYP that contributes to drug-induced liver toxicity.

Drug Induced Steatohepatitis: An Uncommon Culprit of a Common Disease

Nonalcoholic fatty liver disease (NAFLD) is a leading cause of liver disease in developed countries. Its frequency is increasing in the general population mostly due to the widespread occurrence of obesity and the metabolic syndrome. Although drugs and dietary supplements are viewed as a major cause of acute liver injury, drug induced steatosis and steatohepatitis are considered a rare form of drug induced liver injury (DILI). The complex mechanism leading to hepatic steatosis caused by commonly used drugs such as amiodarone, methotrexate, tamoxifen, valproic acid, glucocorticoids, and others is not fully understood. It relates not only to induction of the metabolic syndrome by some drugs but also to their impact on important molecular pathways including increased hepatocytes lipogenesis, decreased secretion of fatty acids, and interruption of mitochondrial β-oxidation as well as altered expression of genes responsible for drug metabolism. Better familiarity with this type of liver injury is important for early recognition of drug hepatotoxicity and crucial for preventing severe forms of liver injury and cirrhosis. Moreover, understanding the mechanisms leading to drug induced hepatic steatosis may provide much needed clues to the mechanism and potential prevention of the more common form of metabolic steatohepatitis.

Drug-drug interactions with oral anti-HCV agents and idiosyncratic hepatotoxicity in the liver transplant setting

Studies of boceprevir and telaprevir based antiviral therapy in liver transplant (LT) recipients with hepatitis C genotype 1 infection have demonstrated dramatic increases in tacrolimus, cyclosporine, and mTOR inhibitor exposure. In addition to empiric dose reductions, daily monitoring of immunosuppressant blood levels is required when initiating as well as discontinuing the protease inhibitors to maximize patient safety. Although improved suppression of HCV replication is anticipated, 20 to 40% of treated subjects have required early treatment discontinuation due to various adverse events including anemia (100%), infection (30%), nephrotoxicity (20%) and rejection (5 to 10%). Simeprevir and faldaprevir will likely have improved efficacy and safety profiles but potential drug interactions with other OATP1B1 substrates and unconjugated hyperbilirubinemia are expected. In contrast, sofosbuvir and daclatasvir based antiviral therapy are not expected to lead to clinically significant drug-drug interactions in LT recipients but confirmatory studies are needed. Liver transplant recipients may also be at increased risk of developing drug induced liver injury (DILI). Establishing a diagnosis of DILI in the transplant setting is very difficult with the variable latency, laboratory features and histopathological manifestations of hepatotoxicity associated with a given drug, the need to exclude competing causes of allograft injury, and the lack of an objective and verifiable confirmatory test. Nonetheless, a heightened awareness of the possibility of DILI is warranted in light of the large number of medications used in LT recipients and the potential adverse impact that DILI may have on patient outcomes.

Hyperacute drug-induced hepatitis with intravenous amiodarone: case report and review of the literature

Amiodarone is a benzofuran class III antiarrhythmic drug used to treat a wide spectrum of ventricular tachyarrhythmias. The parenteral formulation is prepared in polysorbate 80 diluent. We report an unusual case of acute elevation of aminotransaminase concentrations after the initiation of intravenous amiodarone. An 88-year-old Caucasian female developed acute hepatitis and renal failure after initiating intravenous amiodarone for atrial fibrillation with a rapid ventricular response in the setting of acutely decompensated heart failure and hepatic congestion. Liver transaminases returned to baseline within 7 days after discontinuing the drug. Researchers hypothesized that this type of injury is related to liver ischemia with possible superimposed direct drug toxicity. The CIOMS/RUCAM scale identifies our patient's acute hepatitis as a highly probable adverse drug reaction. Future research is needed to understand the mechanisms by which hyperacute drug toxicity occurs in the setting of impaired hepatic perfusion and venous congestion.

Roles of the hemostatic system and neutrophils in liver injury from co-exposure to amiodarone and lipopolysaccharide

It has been demonstrated that co-treatment of rats with amiodarone (AMD) and bacterial lipopolysaccharide (LPS) produces idiosyncrasy-like liver injury. In this study, the hypothesis that the hemostatic system and neutrophils contribute to AMD/LPS-induced liver injury was explored. Rats were treated with AMD (400 mg/kg, ip) or vehicle and 16 h later with LPS (1.6×10⁶ endotoxin units/kg, iv) or saline (Sal). AMD did not affect the hemostatic system by itself but significantly potentiated LPS-induced coagulation activation and fibrinolysis impairment. Increased hepatic fibrin deposition and subsequent hypoxia were observed only in AMD/LPS-treated animals, starting before the onset of liver injury. Administration of anticoagulant heparin abolished AMD/LPS-induced hepatic fibrin deposition and reduced AMD/LPS-induced liver damage. Polymorphonuclear neutrophils (PMNs) accumulated in liver after treatment with LPS or AMD/LPS, but PMN activation was only observed in AMD/LPS-treated rats. Rabbit anti-rat PMN serum, which reduced accumulation of PMNs in liver, prevented PMN activation and attenuated AMD/LPS-induced liver injury in rats. PMN depletion did not affect hepatic fibrin deposition. Anticoagulation prevented PMN activation without affecting PMN accumulation. In summary, both the hemostatic system alteration and PMN activation contributed to AMD/LPS-induced liver injury in rats, in which fibrin deposition was critical for the activation of PMNs.

Amiodarone-induced cirrhosis of liver: what predicts mortality?

Introduction. Amiodarone has been used for more than 5 decades for the treatment of various tachyarrhythmias and previously for the treatment of refractory angina. There are multiple well-established side effects of amiodarone. However, amiodarone-induced cirrhosis (AIC) of liver is an underrecognized complication. Methods. A systematic search of Medline from January 1970 to November 2012 by using the following terms, amiodarone and cirrhosis, identified 37 reported cases of which 30 were used in this analysis. Patients were divided into 2 subsets, survivors versus nonsurvivors, at 5 months. Results. Aspartate aminotransferase was significantly lower (P = 0.03) in patients who survived at 5-months (mean 103.33 IU/L) compared to nonsurvivors (mean 216.88 IU/L). There was no statistical difference in the levels of prothrombin time, total bilirubin, alanine aminotransferase, alkaline phosphatase, gamma-glutamyl transpeptidase, cumulative dose, and latency period between the two groups. The prevalence of DM, HTN, HLD, CAD, and CHF was similar in the two groups. None of the above-mentioned variables could be identified as a predictor of survival at 5 months. Conclusion. AIC carries a mortality risk of 60% at 5 months once the diagnosis is established. Further prospective studies are needed to identify predictors of AIC and of mortality or survival in cases of AIC.

Effects of dronedarone started rapidly after amiodarone discontinuation

BACKGROUND

Multiple studies have shown that amiodarone is effective in treating atrial fibrillation (AF), but is associated with a relatively high incidence of side effects; however, due to amiodarone's long elimination half-life (20-100 days), physicians may hesitate to start other drugs until it has fully cleared.

HYPOTHESIS

A rapid switch from amiodarone to dronedarone is feasible.

METHODS

EURIDIS and ADONIS were double-blind, multinational, parallel-group trials comparing the efficacy and safety of dronedarone with placebo over 12 months. This retrospective subanalysis of EURIDIS/ADONIS compared the effects of dronedarone in patients discontinuing amiodarone within 2 days before randomization ("rapid switch") with results in patients who had received no amiodarone during the 2 months preceding randomization.

RESULTS

In total, 1237 patients were enrolled ("rapid switch", n = 154; "no amiodarone", n = 1014). In both the "rapid switch" and the "no amiodarone" groups, dronedarone users had significantly lower AF recurrence than patients receiving placebo (HR = 0.64, 95% CI, 0.44-0.95; P = 0.0224 and HR = 0.79, 95% CI, 0.67-0.92; P = 0.0027, respectively). Dronedarone users had a higher incidence of bradyarrhythmic events than placebo-treated patients. A "rapid switch" from amiodarone to dronedarone was associated with a higher incidence of serious heart failure events and heart failure hospitalizations versus all other groups. Overall event rates were low and there was no significant difference in total adverse event rates or deaths between groups.

CONCLUSION

In this patient population, a switch from amiodarone to dronedarone within a 2-day time frame might be feasible in certain patient categories, but further investigation is warranted.

Acute hepatic failure following intravenous amiodarone

A 73-year-old gentleman presented to the hospital after an episode of loss of consciousness. He had a defibrillator in situ, which on interrogation was found to have fired for an episode of ventricular fibrillation. As an inpatient he developed frequent episodes of self-terminating ventricular tachycardia, treated initially with oral amiodarone. A 24 h amiodarone infusion was started on day 3 of admission, following which the patient developed hyperventilation. Investigations revealed that this was secondary to acute hepatic and renal failure, requiring haemofiltration on the intensive care unit. Cessation of amiodarone was associated with normalisation of liver function over 48 h. The patient had normal blood and jugular venous pressures throughout days 1-4 of admission. We discuss the role of amiodarone as the predominant factor in the deterioration of this patient's liver function, versus the differential diagnosis of ischaemia-induced hepatotoxicity, citing recent research regarding this subject.

Hepatotoxicity after continuous amiodarone infusion in a postoperative cardiac infant

A former 34-week-old female infant with Down syndrome underwent surgical correction of a congenital heart defect at 5 months of age. Her postoperative course was complicated by severe pulmonary hypertension and junctional ectopic tachycardia. Following treatment with amiodarone infusion, she developed laboratory indices of acute liver injury. At their peak, liver transaminase levels were 19 to 35 times greater than the upper limit of normal. Transaminitis was accompanied by coagulopathy, hyperammonemia, and high serum lactate and lipid levels. Hepatic laboratory abnormalities began to resolve within 48 hr of stopping amiodarone infusion. Heart rate control was achieved concurrently with discovery of laboratory test result abnormalities, and no further antiarrhythmic therapy was required. The intravenous formulation of amiodarone contains the diluent polysorbate 80, which may have hepatotoxic effects. Specifically, animal studies suggest that polysorbate 80 may destabilize cell membranes and predispose to fatty change within liver architecture. Polysorbate was implicated in infant fatalities from E-ferol use in the 1980s. This case illustrates a possible adverse event by the Naranjo probability scale. Given the extent of clinically apparent hepatic injury, this patient was not rechallenged with amiodarone during the remainder of her hospitalization. With amiodarone now used as first-line pharmacologic therapy for critical tachyarrhythmia in this population, the number of children exposed to this drug should be expected to increase. Laboratory indices of liver function should be evaluated at initiation of amiodarone therapy, as well as frequently throughout duration of therapy. Consideration should be given to polysorbate-free formulation of intravenous amiodarone for use in the cohort with congenital cardiac disease.

Tumor necrosis factor-alpha potentiates the cytotoxicity of amiodarone in Hepa1c1c7 cells: roles of caspase activation and oxidative stress

Amiodarone (AMD), a class III antiarrhythmic drug, causes idiosyncratic hepatotoxicity in human patients. We demonstrated previously that tumor necrosis factor-alpha (TNF-α) plays an important role in a rat model of AMD-induced hepatotoxicity under inflammatory stress. In this study, we developed a model in vitro to study the roles of caspase activation and oxidative stress in TNF potentiation of AMD cytotoxicity. AMD caused cell death in Hepa1c1c7 cells, and TNF cotreatment potentiated its toxicity. Activation of caspases 9 and 3/7 was observed in AMD/TNF-cotreated cells, and caspase inhibitors provided minor protection from cytotoxicity. Intracellular reactive oxygen species (ROS) generation and lipid peroxidation were observed after treatment with AMD and were further elevated by TNF cotreatment. Adding water-soluble antioxidants (trolox, N-acetylcysteine, glutathione, or ascorbate) produced only minor attenuation of AMD/TNF-induced cytotoxicity and did not influence the effect of AMD alone. On the other hand, α-tocopherol (TOCO), which reduced lipid peroxidation and ROS generation, prevented AMD toxicity and caused pronounced reduction in cytotoxicity from AMD/TNF cotreatment. α-TOCO plus a pancaspase inhibitor completely abolished AMD/TNF-induced cytotoxicity. In summary, activation of caspases and oxidative stress were observed after AMD/TNF cotreatment, and caspase inhibitors and a lipid-soluble free-radical scavenger attenuated AMD/TNF-induced cytotoxicity.

Acute hepatitis secondary to parenteral amiodarone does not preclude subsequent oral therapy

Amiodarone chlorhydrate is a diiodated benzofuran derivative used to treat cardiac rhythm abnormalities. Hepatotoxicity is a relatively uncommon side effect of amiodarone and symptomatic hepatic dysfunction occurs in less than 1% to 3% of patients taking amiodarone. We report here on an unusual case of amiodarone-induced hepatotoxicity. A 29 year old woman with normal liver function was given amiodarone intravenously to treat her atrial fibrillation. She developed acute toxic hepatitis after 24 h. The intravenous form of amiodarone was immediately avoided and replaced by the oral form, using conventional loading doses as soon as the deranged liver function tests had normalized, without recurrence of the hepatitis. These observations show that the occurrence of acute hepatic impairment with intravenous amiodarone does not necessarily preclude the use of this drug by mouth and the necessity of monitoring the hepatic function of patients treated with amiodarone.

Amiodarone exposure during modest inflammation induces idiosyncrasy-like liver injury in rats: role of tumor necrosis factor-alpha

Amiodarone [2-butyl-3-(3′,5′-diiodo-4’α-diethylaminoethoxybenzoyl)-benzofuran] (AMD), a class III antiarrhythmic drug, is known to cause idiosyncratic hepatotoxic reactions in human patients. One hypothesis for the etiology of idiosyncratic adverse drug reactions is that a concurrent inflammatory stress results in decreased threshold for drug toxicity. To explore this hypothesis in an animal model, male Sprague-Dawley rats were treated with nonhepatotoxic doses of AMD or its vehicle and with saline vehicle or lipopolysaccharide (LPS) to induce low-level inflammation. Elevated alanine aminotransferase (ALT), aspartate aminotransferase, alkaline phosphatase, and gamma-glutamyltransferase activities as well as increased total bile acid concentrations in serum and midzonal hepatocellular necrosis were observed only in AMD/LPS-cotreated rats. The time interval between AMD and LPS administration was critical: AMD injected 16 h before LPS led to liver injury, whereas AMD injected 2–12 h before LPS failed to cause this response. The increase in ALT activity in AMD/LPS cotreatment showed a clear dose-response relationship with AMD as well as LPS. The metabolism and hepatic accumulation of AMD were not affected by LPS coexposure. Serum concentration of tumor necrosis factor-alpha (TNF) was significantly increased by LPS and was slightly prolonged by AMD. In Hepac1c7 cells, addition of TNF potentiated the cytotoxicity of both AMD and its primary metabolite, mono-N-desethylamiodarone. In vivo inhibition of TNF signaling by etanercept attenuated the AMD/LPS-induced liver injury in rats. In summary, AMD treatment during modest inflammation induced severe hepatotoxicity in rats, and TNF contributed to the induction of liver injury in this animal model of idiosyncratic AMD-induced liver injury.

Acute liver injury after intravenous amiodarone: a case report

Acute hepatotoxicity is a rare but potentially fatal complication of amiodarone use. Although oral long-term use of the drug is frequently complicated by an asymptomatic rise in serum aminotransferase concentrations, acute hepatotoxicity during intravenous loading is much less frequent and potentially fatal. We report a case of liver injury after intravenous administration in a patient with atrial fibrillation.

A Patient Case: Intravenous Azithromycin-Induced Hepatotoxicity

Objective

To report a case of probable hepatotoxicity associated with intravenous (IV) azithromycin.

Case Summary

A 61-year-old white male was admitted to the hospital with shortness of breath and a subsequent diagnosis of community-acquired pneumonia. The patient's aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were within normal limits. The patient was started on piperacillin/tazobactam 2.25 mg IV every 8 hours and ceftriaxone 1 g IV daily. On day 2 of hospitalization, azithromycin 500 mg IV once daily was initiated. On day 4, the patient's AST increased to 1,594 international units/liter (IU/L) and ALT to 650 IU/L. The ALT/AST peaked on day 6 of hospitalization. The patient's AST and ALT trended downward after discontinuation of the azithromycin.

Discussion

The Naranjo probability scale rated the patient's hepatotoxicity as a probable adverse reaction related to azithromycin toxicity. Two case reports have documented an association with oral azithromycin and hepatotoxicity.

Conclusion

This case report documents an acute increase in ALT and AST levels associated with IV administration of azithromycin. Health care professionals may consider monitoring AST and ALT in patients at risk for hepatic dysfunction with IV administration of azithromycin.

Clinical Applications and Acute Hepatotoxicity of Intravenous Amiodarone

This cross-sectional, retrospective study was designed to evaluate the current clinical applications and acute hepatotoxicity of intravenous amiodarone administration at a hospital in China. Clinical data were collected from 1214 patients receiving intravenous amiodarone treatment between October 2003 and September 2005. Baseline patient characteristics, drug indications, administration records and acute hepatotoxicity associated with the drug were examined. Amiodarone was used primarily in arrhythmic patients with obvious cardiac dysfunction. Atrial fibrillation and ventricular arrhythmia were the two most commonly treated dysfunctions. Incorrect indications and administration methods were also noted. Hepatotoxicity occurred in 12.6% of the patients, but was mild in most cases. Males showed a higher incidence of hepatotoxicity than females. The use of amiodarone was considered to be reasonable and standardized, but there was still considerable room for improvement, particularly in the standardization of administration guidelines. Intravenous amiodarone can cause hepatotoxicity and hepatic function tests should be performed soon after giving amiodarone intravenously.

Amiodarone pretreatment of organ donors exerts anti-oxidative protection but induces excretory dysfunction in liver preservation and reperfusion

The continuous shortage of organs necessitates the use of marginal organs from donors with various diseases, including arrhythmia-associated cardiac failure. One of the most frequently used anti-arrhythmic drugs is amiodarone (AM), which is given in particular in emergency situations. Apart from its anti-arrhythmic actions, AM provides anti-oxidative properties in cardiomyocytes. Thus, we were interested in whether AM donor pretreatment affects the organ quality and function of livers procured for preservation and transplantation. Donor rats were pretreated with AM (5 mg/kg of body weight) 10 minutes before flush-out of the liver with a cold (4 degrees C) histidine-tryptophan-ketoglutarate solution (n = 8). Livers were then stored for 24 hours at 4 degrees C before ex situ reperfusion with a 37 degrees C Krebs-Henseleit solution for 60 minutes in a nonrecirculating system. At the end of reperfusion, tissue samples were taken for histology and Western blot analysis. Animals with vehicle only (0.9% NaCl) served as ischemia/reperfusion controls (n = 8). Additionally, livers of untreated animals (n = 8) not subjected to 24 hours of cold ischemia served as sham controls. AM pretreatment effectively attenuated lipid peroxidation, stress protein expression, and apoptotic cell death. This was indicated by an AM-mediated reduction of malondialdehyde, heme oxygenase-1, and caspase-3 activation. However, AM treatment also induced mitochondrial damage and hepatocellular excretory dysfunction, as indicated by a significantly increased glutamate dehydrogenase concentration in the effluate and decreased bile production. In conclusion, AM donor pretreatment exerts anti-oxidative actions in liver preservation and reperfusion. However, these protective AM actions are counteracted by an induction of mitochondrial damage and hepatocellular dysfunction. Accordingly, AM pretreatment of donors for anti-arrhythmic therapy should be performed with caution.

No elevation of glutathione S-transferase-a1-1 by amiodarone loading in intensive care unit patients with atrial fibrillation

Hepatocellular toxicity is a putative side-effect of amiodarone. The hepatic detoxification enzyme glutathione S-transferase-A1-1 (GSTA1-1) is a sensitive indicator of hepatocellular damage. We investigated the occurrence of subclinical liver injury, as measured by plasma GSTA1-1 in intensive care unit patients with atrial fibrillation receiving amiodarone. Sixteen haemodynamically stable intensive care unit patients with atrial fibrillation were treated with amiodarone intravenously. Patients were given a loading dose of 150 mg followed by another 150 mg followed by a continuous infusion of 1200 mg/hour if atrial fibrillation persisted. Blood samples for GSTA1-1 (measured by an enzyme-linked immunosorbent assay) were taken at zero, one, three, six, 12 and 24 hours, transaminases and bilirubin at zero, six, 12 and 24 hours. Blood pressure and heart rate were continuously monitored. Effects were analysed for time-dependent changes (one-way analysis of variance for repeated measures). Blood pressure increased from 125 +/- 8/60 +/- 3 mmHg at t = 0 to 144 +/- 9/66 +/- 4 mmHg at t = 24 hours (P < 0.05), heart rate decreased from atrial fibrillation 124 +/- 5 to sinus rhythm 86 +/- 6 beats per minute (P < 0.05). There was no significant elevation of GSTA1-1, transaminases or bilirubin during the observation period of 24 hours. Amiodarone does not cause elevation of GSTA1-1 as a marker of subclinical liver injury in haemodynamically stable intensive care unit patients with atrial fibrillation.

Hepatotoxicity after intravenous amiodarone

Amiodarone is a class III antiarrhythmic agent with a long half-life which is used to control atrial and ventricular arrhythmias, including atrial flutter and fibrillation. We describe here the case of an elderly woman (77 years of age) who was hospitalized for acute atrial fibrillation, abdominal pain, and dyspnea. In the Emergency Department, treatment with intravenous amiodarone was begun. The following day, the patient developed acute liver damage; improved liver function occurred following the withdrawal of amiodarone. Complete recovery of liver function was documented after three weeks. Unfortunately, the patient died from a severe infectious disease, with multiple organ failure.

Mitochondrial dysfunction and delayed hepatotoxicity: another lesson from troglitazone

AIMS/HYPOTHESIS

Troglitazone was approved for treatment of type 2 diabetes mellitus, but by 2000 it had been removed from all world markets due to severe drug-induced liver injury. Even today, we still do not know how many patients sustained a long-term liver injury. No system is in place to acquire that knowledge. Regarding toxicity mechanisms, controversy persists as to which ones are class effects of thiazolidinediones (TZDs) and which are unique to troglitazone. This study aims to provide long-term outcome data and new insights on mechanisms of troglitazone-induced liver injury.

METHODS

This case series reports the liver injuries sustained by eleven type 2 diabetic patients treated with troglitazone between 1997 and 2000. Exhaustive review of medical records was performed for all patients. Long-term outcomes were available for all the non-fatal cases. A comprehensive literature review was also performed.

RESULTS

Long-term liver injury progressing to cirrhosis was identified in seven patients. All eleven cases had liver injury patterns consistent with troglitazone toxicity. Analysis of these cases and of the experimental troglitazone toxicity data points to mitochondrial toxicity as a central factor. The general clinical patterns of mitochondrial hepatotoxic events are reviewed, as are the implications for other members of the TZD family.

CONCLUSIONS/INTERPRETATION

This analysis enables the liver injury induced by troglitazone to be better understood. In future cases of delayed drug-induced liver injury that progresses after discontinuation, the possibility of mitochondrial toxicity should be considered. When appropriate, this can then be evaluated experimentally. Such proactive investigation may anticipate clinical risk before a large-scale therapeutic misadventure occurs. Drug-induced liver injury due to mitochondrial hepatotoxins may be less unpredictable than has previously been surmised.

Efficacy of magnesium-amiodarone step-up scheme in critically ill patients with new-onset atrial fibrillation: a prospective observational study

Amiodarone is considered a first-choice antiarrhythmic drug in critically ill patients with new-onset atrial fibrillation (AF). However, evidence supporting the use of this potentially toxic drug in critically ill patients is scarce. Magnesium sulphate (MgSO4) has shown to be effective for both rate and rhythm control, to act synergistically with antiarrhythmic drugs, and to prevent proarrhythmia. Treatment with MgSO4 may reduce the need for antiarrhythmic drugs such as amiodarone in critically ill patients with new-onset atrial fibrillation. The efficacy of a new institutional protocol was evaluated. Patients were treated with a new institutional protocol for new-onset atrial fibrillation in critically ill patients. An MgSO4 bolus (0.037 g/kg body weight in 15 minutes) was followed by continuous infusion (0.025 g/kg body weight/h). Intravenous amiodarone (loading dose 300 mg, followed by continuous infusion of 1200 mg/24 h) was given to those not responding to MgSO4 within 1 hour. Clinical response was defined as conversion to sinus rhythm or decrease in heart rate <110 beats/min. Sixteen of the 29 patients responded to MgSO4 monotherapy, whereas the addition of amiodarone was needed in 13 patients. Median (range) time until conversion to sinus rhythm after MgSO4 was 2 (1-45) hours. Median (range) conversion time in patients requiring amiodarone was 4 (2-78) hours, and median (range) conversion time in all patients was 3 (1-78) hours. The 24-hour conversion rate was 90%. Relapse atrial fibrillation was seen in 7 patients. The magnesium-amiodarone step-up scheme reduces the need for amiodarone, effectively converts new-onset atrial fibrillation into a sinus rhythm within 24 hours, and seems to be safe in critically ill patients.

Clinical review: treatment of new-onset atrial fibrillation in medical intensive care patients--a clinical framework

Atrial fibrillation occurs frequently in medical intensive care unit patients. Most intensivists tend to treat this rhythm disorder because they believe it is detrimental. Whether atrial fibrillation contributes to morbidity and/or mortality and whether atrial fibrillation is an epiphenomenon of severe disease, however, are not clear. As a consequence, it is unknown whether treatment of the arrhythmia affects the outcome. Furthermore, if treatment is deemed necessary, it is not known what the best treatment is. We developed a treatment protocol by searching for the best evidence. Because studies in medical intensive care unit patients are scarce, the evidence comes mainly from extrapolation of data derived from other patient groups. We propose a treatment strategy with magnesium infusion followed by amiodarone in case of failure. Although this strategy seems to be effective in both rhythm control and rate control, the mortality remained high. A randomised controlled trial in medical intensive care unit patients with placebo treatment in the control arm is therefore still defendable.

Effects of an adapted intravenous amiodarone treatment protocol in horses with atrial fibrillation

REASON FOR PERFORMING STUDY

Good results have been obtained with a human amiodarone (AD) i.v. protocol in horses with chronic atrial fibrillation (AF) and a pharmacokinetic study is required for a specific i.v. amiodarone treatment protocol for horses.

OBJECTIVES

To study the efficacy of this pharmacokinetic based i.v. AD protocol in horses with chronic AF.

METHODS

Six horses with chronic AF were treated with an adapted AD infusion protocol. The protocol consisted of 2 phases with a loading dose followed by a maintenance infusion. In the first phase, horses received an infusion of 6.52 mg AD/kg bwt/h for 1 h followed by 1.1 mg/kg bwt/h for 47 h. In the second phase, horses received a second loading dose of 3.74 mg AD/kg bwt/h for 1 h followed by 1.31 mg/kg bwt/h for 47 h. Clinical signs were monitored, a surface ECG and an intra-atrial electrogram were recorded. AD treatment was discontinued when conversion or any side effects were observed.

RESULTS

Three of the 6 horses cardioverted successfully without side effects. The other 3 horses did not convert and showed adverse effects, including diarrhoea. In the latter, there were no important circulatory problems, but the diarrhoea continued for 10-14 days. The third horse had to be subjected to euthanasia because a concomitant Salmonella infection worsened the clinical signs.

CONCLUSION

The applied treatment protocol based upon pharmacokinetic data achieved clinically relevant concentrations of AD and desethylamiodarone.

POTENTIAL RELEVANCE

Intravenous AD has the potential to be an alternative pharmacological treatment for AF in horses, although AD may lead to adverse drug effects, particularly with cumulative dosing.

Amiodarone Prophylaxis: Impact on Atrial Fibrillation and Outcomes after Cardiac Surgery

This continuing feature will update readers on recent developments in cardiovascular pharmacotherapy. Cardiovascular disease remains the number one killer in the United States, and more clinical outcome trials have been conducted in cardiology than in any other field of medicine. Given this rapidly expanding knowledge base, pharmacists can have a significant impact on prevention and treatment—if they keep current with developments in drug therapy.