Amiodarone-induced hepatic phospholipidosis: correlation of morphological and biochemical findings in an animal model

Microphysiological Models for Mechanistic-Based Prediction of Idiosyncratic DILI

Drug-induced liver injury (DILI) is a major contributor to high attrition rates among candidate and market drugs and a key regulatory, industry, and global health concern. While acute and dose-dependent DILI, namely, intrinsic DILI, is predictable and often reproducible in preclinical models, the nature of idiosyncratic DILI (iDILI) limits its mechanistic understanding due to the complex disease pathogenesis, and recapitulation using in vitro and in vivo models is extremely challenging. However, hepatic inflammation is a key feature of iDILI primarily orchestrated by the innate and adaptive immune system. This review summarizes the in vitro co-culture models that exploit the role of the immune system to investigate iDILI. Particularly, this review focuses on advancements in human-based 3D multicellular models attempting to supplement in vivo models that often lack predictability and display interspecies variations. Exploiting the immune-mediated mechanisms of iDILI, the inclusion of non-parenchymal cells in these hepatoxicity models, namely, Kupffer cells, stellate cells, dendritic cells, and liver sinusoidal endothelial cells, introduces heterotypic cell-cell interactions and mimics the hepatic microenvironment. Additionally, drugs recalled from the market in the US between 1996-2010 that were studies in these various models highlight the necessity for further harmonization and comparison of model characteristics. Challenges regarding disease-related endpoints, mimicking 3D architecture with different cell-cell contact, cell source, and the underlying multi-cellular and multi-stage mechanisms are described. It is our belief that progressing our understanding of the underlying pathogenesis of iDILI will provide mechanistic clues and a method for drug safety screening to better predict liver injury in clinical trials and post-marketing.

Iodine accumulation of the liver in patients treated with amiodarone can be unmasked using material decomposition from multiphase spectral-detector CT

Amiodarone accumulates in the liver, where it increases x-ray attenuation due to its iodine content. We evaluated liver attenuation in patients treated and not treated with amiodarone using true-non-contrast (TNC) and virtual-non-contrast (VNC) images acquired with spectral-detector-CT (SDCT). 142 patients, of which 21 have been treated with amiodarone, receiving SDCT-examinations (unenhanced-chest CT [TNC], CT-angiography of chest and abdomen [CTA-Chest, CTA-Abdomen]) were included. TNC, CTA-Chest, CTA-Abdomen, and corresponding VNC-images (VNC-Chest, VNC-Abdomen) were reconstructed. Liver-attenuation-index (LAI) was calculated as difference between liver- and spleen-attenuation. Liver-attenuation and LAI derived from TNC-images of patients receiving amiodarone were higher. Contrary to TNC, liver-attenuation and LAI were not higher in amiodarone patients in VNC-Chest and in VNC-Abdomen. To verify these initial results, a phantom scan was performed and an additional patient cohort included, both confirming that VNC is viable of accurately subtracting iodine of hepatic amiodarone-deposits. This might help to monitor liver-attenuation more accurately and thereby detect liver steatosis as a sign of liver damage earlier as well as to verify amiodarone accumulation in the liver.

Use of 3D Human Liver Organoids to Predict Drug-Induced Phospholipidosis

Drug-induced phospholipidosis (PL) is a storage disorder caused by the formation of phospholipid-drug complexes in lysosomes. Because of the diversity of PL between species, human cell-based assays have been used to predict drug-induced PL in humans. We established three-dimensional (3D) human liver organoids as described previously and investigated their liver characteristics through multiple analyses. Drug-induced PL was initiated in these organoids and in monolayer HepG2 cultures, and cellular changes were systemically examined. Organoids that underwent differentiation showed characteristics of hepatocytes rather than HepG2 cells. The organoids also survived under PL-inducing drug conditions for 48 h and maintained a more stable albumin secretion level than the HepG2 cells. More cytoplasmic vacuoles were observed in organoids and HepG2 cells treated with more potent PL-induced drugs, but to a greater extent in organoids than in HepG2 cells. Lysosome-associated membrane protein 2, a marker of lysosome membranes, showed a stronger immunohistochemical signal in the organoids. PL-distinctive lamellar bodies were observed only in amiodarone-treated organoids by transmission electron microscopy. Human liver organoids are thus more sensitive to drug-induced PL and less affected by cytotoxicity than HepG2 cells. Since PL is a chronic condition, these results indicate that organoids better reflect metabolite-mediated hepatotoxicity in vivo and could be a valuable system for evaluating the phospholipidogenic effects of different compounds during drug development.

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.

Trends in reporting drug-associated liver injuries in Taiwan: a focus on amiodarone

Background A pharmacovigilance database of real-world adverse drug reaction (ADR) reports is helpful for characterising adverse events and identifying new signals after drug approval. Objective This study aimed to analyse trends of ADR reporting in relation to liver injury and to delineate critical factors for suspected drug-related hepatotoxicity with a focus on reports associated with amiodarone. Setting The 2000-2014 Taiwan pharmacovigilance database. Method Relevant Standardized Medical Dictionary for Regulatory Activities queries were used to identify reports associated with liver injury. Information on ADR, patient characteristics, and the verbatim pertaining to amiodarone prescriptions, liver injury, comedications, and comorbidities were extracted and evaluated. Group comparisons between Hy's Law cases and Temple's Corollary cases of suspected amiodarone-related hepatotoxicity were performed. Main outcome measure Number and nature of drug-related liver injuries, particularly those associated with amiodarone. Results Of the 98,777 ADR reports over a 15-year period, 4261 (4.3%) were related to liver injury. Sixty-eight reports contained amiodarone prescriptions, but only 49 (1.1%) were eligible for further analysis. Hepatotoxic cases associated with amiodarone mostly occurred within 1 week, exhibited a hepatocellular pattern, and were more common among elderly individuals. Among 23 discernible cases, four (17.4%) recovered fully from liver injury. The critical Hy's Law cases were associated with shorter height, lower body surface area, and higher average daily doses. Conclusion This study substantiates the importance of ADR reporting. Data pertaining to drug-associated liver injury and factors associated with suspected amiodarone-related hepatotoxicity warrants continual attention in pharmacovigilance for those at risk, especially the elderly.

Detection of nanocarrier potentiation on drug induced phospholipidosis in cultured cells and primary hepatocyte spheroids by high content imaging and analysis

Considerable effort has been made to develop nanocarriers for controlled drug delivery over the last decade, while it remains unclear how the strength of adverse drug effect will be altered when a drug is loaded on the nanocarrier. Drug-induced phospholipidosis (DIP) is characterized with excessive accumulation of phospholipids in cells and is common for cationic amphiphilic drugs (CAD). Previously, we have reported that PEGylated graphene oxide (PEG-GO) loaded with several CAD can potentiate DIP. In current study, we extended our study on newly identified phospholipidosis (PLD) inducers that had been identified from the Library of Pharmacologically Active Compounds (LOPAC), to investigate if PEO-GO loaded with these CAD can alter DIP. Twenty-two CAD were respectively loaded on PEG-GO and incubated with RAW264.7, a macrophage cell line. The results showed that when a CAD was loaded on PEG-GO, its strength of PLD induction can be enhanced, unchanged or attenuated. PEG-GO loaded with Ifenprodil exhibited the highest PEG-GO potentiation effect compared to Ifenprodil treatment alone in RAW264.7 cells, and this effect was confirmed in human hepatocellular carcinoma HepG2, another cell line model for PLD induction. Primary hepatocyte culture and spheroids mimicking in vivo conditions were used to further validate nanocarrier potentiation on DIP by Ifenprodil. Stronger phospholipid accumulation was found in PEG-GO/Ifenprodil treated hepatocytes or spheroids than Ifenprodil treatment alone. Therefore, evidences were provided by us that nanocarriers may increase the adverse drug effects and guidance by regulatory agencies need to be drafted for the safe use of nanotechnology in drug delivery.

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.

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.

Amiodarone-induced hepatitis and polyneuropathy

Amiodarone chlorhydrate is a diiodated benzofuran derivative, and it is used to treat cardiac rhythm abnormalities. Hepatotoxicity is a relatively uncommon side effect of amiodarone, and symptomatic hepatic dysfunction occurs in fewer than 1% of the patients taking amiodarone. Cirrhosis is a rare complication that's been confirmed in 12 cases. Peripheral neuropathy occurs in 10% of patients taking aminodarone. We report here on an unusual case of amiodarone-induced hepatotoxicity and peripheral neurotoxicity. A 75 year old man with normal liver function was given amiodarone for treating his atrial fibrillation and heart failure. He developed nausea, vomiting, muscle weakness and wasting after 17.8 months therapy with amiodarone (400 mg orally once per day). Liver biopsy showed the presence of foam cells in the hepatic sinusoids and Mallory bodies in the periportal hepatocytes on light microscopy. Sural nerve biopsy showed demyelination, and nerve conduction studies showed mixed sensorimotor polyneuropathy. These observations show the necessity of monitoring the hepatic function and conducting neurologic examination of the patients treated with amiodarone.

Hepatic cirrhosis caused by low-dose oral amiodarone therapy

A 63-year-old man presented with ascites after therapy with amiodarone, 200 mg orally once per day for 22.5 months. A liver biopsy showed grade 3 chronic hepatitis and micronodular cirrhosis. The presence of striking microvesicular steatosis on light microscopy and lysosomal inclusion bodies on electron microscopy suggested amiodarone hepatotoxicity. This is the first reported case of amiodarone-induced hepatic cirrhosis associated with chronic treatment with 200 mg orally once per day for less than 2 years.

Amiodarone-induced disruption of hamster lung and liver mitochondrial function: lack of association with thiobarbituric acid-reactive substance production

Amiodarone (AM) is an efficacious antidysrhythmic agent that is limited clinically by numerous adverse effects. Of greatest concern is AM-induced pulmonary toxicity (AIPT) due to the potential for mortality. Mitochondrial alterations and free radicals have been implicated in the etiology of AM-induced toxicities, including AIPT. Isolated hamster lung and liver mitochondria were assessed for AM-induced effects on respiration, membrane potential, and lipid peroxidation. AM (50-400 microM) stimulated state 4 (resting) respiration at complexes I and II of tightly coupled lung mitochondria, with higher concentrations (200 and 400 microM) resulting in a subsequent inhibition. This biphasic effect of AM (200 microM) was also observed with isolated liver mitochondria. Only inhibition of respiration was observed with AM (50-400 microM) in less tightly coupled lung mitochondria. Based on safranine fluorescence, 200 microM AM decreased lung mitochondrial membrane potential (p < 0.05), while a concentration-dependent (50-200 microM) decrease of membrane potential was observed with liver mitochondria exposed to AM (p < 0.05). Formation of thiobarbituric acid-reactive substances (TBARS) was not altered by AM (50-400 microM) in incubations lasting up to 1 h. These results indicate that lipid peroxidation, as indicated by levels of TBARS, does not play a role in AM-induced alterations in mitochondrial respiration and membrane potential.

Cationic amphiphilic drug-induced phospholipidosis

Phospholipidosis, a phospholipid storage disorder, defines an excessive accumulation of intracellular phospholipids. Phospholipids are structural components of mammalian cytoskeleton and cell membranes. The metabolism of this essential cell component is regulated by the individual cell and may be altered by drugs that interact with phospholipids or the enzymes that affect their metabolism. Xenobiotics or their metabolites that induce phospholipidosis include a wide variety of pharmacologic agents, including antibacterials, antipsychotics, antidepressants, antiarrhythmics, antianginals, antimalarials, anorexic agents, cholesterol-lowering agents, and others. Each of these drugs shares several common physiochemical properties: hydrophobic ring structure on the molecule and a hydrophilic side chain with a charged cationic amine group, hence the class term cationic amphiphilic drugs (CADs). This paper reviews the phospholipid metabolism, physiochemical characteristics of CADs, specificity of phospholipidosis in animals and humans, functional effects of phospholipidosis, interaction of CADs with biologic membranes and lysosome metabolism, influence of CADs on phospholipases and phospholipid synthesis, and a proposed mechanism for induction of phospholipidosis in the lung. In human risk assessment, investigators should consider the many factors in evaluating a drug that induces phospholipidosis in animals. These include: the therapeutic class of drug, presence of active metabolites, tissue or organ selectivity in animals and humans, influence of concurrently administered drugs, reversibility of effect, and other factors that increase or decrease the induction of phospholipidosis. Generalities regarding the etiology, incidence, and effect of the drug on a specific host may not be made. Each drug must be evaluated separately to identify the risk when administered for therapeutic effect in humans.

Comparative evaluation of amiodarone-induced phospholipidosis and drug accumulation in Fischer-344 and Sprague-Dawley rats

Amiodarone (AD) and its major metabolite, desethylamiodarone (desethylAD), are both phospholipogenic. The present study was undertaken to evaluate the comparative susceptibilities of male Fischer-344 and Sprague-Dawley rats to AD-induced phospholipidosis in alveolar macrophages (AMs), liver and kidney tissue and the concomitant accumulation of AD and desethylAD in these cells, tissues and plasma. Rats were administered AD (100 mg/kg/day, p.o.) for 1 week. Plasma concentrations of AD and desethylAD were approximately 4- and 12-fold higher, respectively, in Fischer-344s compared to Sprague-Dawleys 24 h after the last dose. AD and desethylAD levels in AMs were approximately 12- and 25-fold higher, respectively, in Fischer-344s than Sprague-Dawleys. In the liver and kidney, levels of both compounds were also significantly higher in Fischer-344s than Sprague-Dawleys. Ultrastructural features indicative of phospholipidosis were not observed consistently in any tissue except AMs from treated Fischer-344s. AM total phospholipid increased nearly 5-fold in Fischer-344s, while Sprague-Dawleys showed no increase over control. AMs from both strains incubated with 10 microM AD or desethylAD in vitro were not significantly different in their accumulation of the compounds. When incubated with AD or desethylAD, the lysosomal phospholipases A1 partially purified from AMs of both strains were equally sensitive to inhibition as measured by the drug concentration giving 50% inhibition in activity (IC50). The results of this study indicate that at the same administered dose, AD and desethylAD, accumulate to higher tissue levels and are more phospholipogenic in male Fischer-344 rats than in male Sprague-Dawley rats. The basis for the high susceptibility of Fischer-344 rats to AM-induced phospholipidosis is unknown at present but appears not to be related to biochemical or cellular features of the AMs.

Cellular accumulation of amiodarone and desethylamiodarone in cultured human cells. Consequences of drug accumulation on cellular lipid metabolism and plasma membrane properties of chronically exposed cells

Amiodarone (AMIO), a potent antiarrhythmic drug, is clinically widely used despite its frequent side effects after chronic administration. These side effects coincide with an intralysosomal accumulation of AMIO and its main metabolite desethylamiodarone (DEA) and may be causally related to the drug-induced intracellular storage of phospholipids (PL). Kinetics of cellular uptake and release of radiolabelled AMIO and DEA were studied following single and multiple exposures of cultured human skin fibroblasts to 5 and 10 microM drug concentrations. AMIO and DEA were efficiently taken up into cultured cells. The rate of uptake was slower than that of other cationic amphiphilic drugs. The intracellular steady state concentrations were in the millimolar range suggesting a lysosomal trapping. Repetitive exposures of cultures resulted in a cumulative and partly saturable drug uptake. The accumulation of DEA was higher than that of AMIO throughout. AMIO and DEA previously taken up into the cells during a 2 hr exposure were completely released into the washing media, suggesting an exchangeable form of the accumulated drugs. Following repetitive exposures only part of the drugs was released. Under chasing conditions using washing media containing non-labelled AMIO and DEA respectively or ammonium chloride the release of the chronically accumulated 14C-labelled drugs was increased. This suggested a drug storage in the form of complexes in acidic compartments. Phospholipid (PL) content as well as individual PL fractions were changed in whole cells and in isolated plasma membranes. PL accumulation is assumed to occur by inhibition of PL degradation due to formation of non-degradable drug-PL complexes or by inhibition of phospholipase activities. Cellular PL accumulation seemed to interfere with PL recycling. Changes in PL composition of purified plasma membranes were in part complementary to the ones in whole cells. The alterations in membrane PL composition may explain the changes in membrane fluidity and the decrease in beta-adrenoceptor density and in isoproterenol-stimulated cAMP formation. The results obtained provide an explanation for the pharmacokinetic, and possibly for the pharmacodynamic and also toxicological behaviour of AMIO and DEA in vivo.

The effect of taurine on the cholestatic potential of sulfated lithocholate and its conjugates

The present study was aimed at determining whether the protection by taurine of lithocholate-sulfate-induced cholestasis is mediated by conjugation or by direct effect of the amino acid on bile formation. Injection of free and conjugated (glycine and taurine) sulfated lithocholate in guinea pigs significantly reduced the secretion rate of non-sulfated bile acids in bile. There was no decrease in bile flow after the injection of taurine-conjugated sulfated lithocholate, which was completely recovered in bile within 60 min. In contrast, injection of sulfated lithocholate and its glycine conjugate led to a marked decrease in bile flow, and neither one was significantly recovered in bile. In addition, both caused morphological changes in the liver, characterized by the accumulation of cytoplasmic vacuoles with lamellated myelin figures characteristic of phospholipidosis. Pretreatment with taurine (0.5% in drinking water for 3 days) prevented both the drop in bile flow and the histological changes in the liver, suggesting that conjugation with taurine removed the cholestatic potential of sulfated lithocholate. However, since taurine was effective not only in preventing cholestasis induced by the free form of sulfated lithocholate but also against its glycine conjugate, these results suggest that other mechanisms in addition to conjugate must be involved.

Amiodarone- and desethylamiodarone-induced myelinoid inclusion bodies and toxicity in cultured rat hepatocytes

Hepatocytes isolated from Sprague-Dawley rats were incubated with various concentrations of either amiodarone or desethylamiodarone for 0 to 96 hr. Both drugs produced a concentration-dependent increase of lactate dehydrogenase release in the culture medium, which correlated well with cell death as measured by trypan blue exclusion test. Desethylamiodarone was more toxic than amiodarone in the cultured hepatocytes. Incubation with subtoxic concentrations of either amiodarone (7.6 microM) or desethylamiodarone (8 microM) for 24 hr resulted in the development of myelinoid inclusion bodies in the hepatocytes without any excess release of lactate dehydrogenase. In experimental protocols where the hepatocytes were exposed to either amiodarone or desethylamiodarone for up to 96 hr, there was an increase in lactate dehydrogenase and the percent volume-density of multilamellar inclusion bodies with cumulative drug exposure with time. A linear correlation between hepatocyte drug concentration and multilamellar inclusion bodies was found for both amiodarone and desethylamiodarone. These results demonstrate that both amiodarone and its major metabolite, desethylamiodarone, induce lysosomal inclusions, which, under appropriate conditions, can be dissociated from cell death. Withdrawal of the drug after 24 hr exposure did not result in disappearance of the inclusion bodies from the hepatocytes for up to 96 hr of tissue culture. The concentrations at which amiodarone- or desethylamiodarone-induced electron microscopic changes and hepatotoxicity were only two to five times as high as the usual serum drug levels in patients given antiarrhythmic therapy with amiodarone.

Differences in hepatic drug accumulation and enzyme induction after chronic amiodarone feeding of two rat strains: role of the hydroxylator phenotype?

1. It has previously been shown that the extent of hepatic phospholipidosis induced by chronic amiodarone treatment correlates with the degree of drug accumulation in liver tissue. 2. To investigate a possible influence of pharmacogenetic factors, biochemical and morphological investigations were carried out in two rat strains differing in debrisoquine hydroxylation. 3. Plasma and liver tissue concentrations of amiodarone and its main metabolite, desethyl-amiodarone, were significantly higher in rats with deficient hydroxylation. Microsomal enzyme induction, drug cytochrome P-450 complex formation and typical ultrastructural features of phospholipidosis were only seen in rats with deficient hydroxylation and in a more sensitive species, the guinea-pig. 4. It remains to be seen whether deficient debrisoquine hydroxylation in man is associated with an increased susceptibility to amiodarone side effects.

Histopathologic analysis of suspected amiodarone hepatotoxicity

This analysis of the morphology of suspected amiodarone (AD) liver disease is based on a study of liver specimens from 17 individuals. Changes similar to alcoholic liver injury were commonly seen. Steatosis, both macrovesicular and microvesicular, was the most frequent histopathologic feature. Ballooning of hepatocytes, Mallory bodies, and fibrosis were also common. Other changes included nuclear unrest, acidophilic bodies, foam cells, glycogenated nuclei, and portal inflammation. Characteristic lamellar lysosomal inclusion bodies representing phospholipidosis were found in two of 14 specimens studied ultrastructurally. These changes of pseudoalcoholic hepatitis and/or phospholipidosis were present in liver specimens from asymptomatic, anicteric patients with mild elevations in serum aminotransferase or alkaline phosphatase values with or without hepatomegaly, as well as in patients with clinically overt symptoms of hepatotoxicity. Phospholipidosis appears to be a generalized systemic effect of cationic amphophilic compounds, such as AD. The cytotoxic pseudoalcoholic changes appear to be an independent phenomenon in susceptible patients, whom we speculate may have been unable or less able to metabolize AD through normal pathways. The true incidence of hepatic injury from AD remains to be determined from prospective evaluations of pretreatment and follow-up liver biopsies.

Amiodarone hepatotoxicity: prevalence and clinicopathologic correlations among 104 patients

The prevalence of apparent amiodarone-related hepatic injury in 104 patients followed prospectively is compared to that reported in the literature. Asymptomatic elevation of serum aminotransferase levels was detected in approximately one-fourth of the patients, a figure similar to the average of reported cases. The frequency of extrahepatic organ toxicity was increased in patients with elevated levels. Symptomatic "hepatitis" developed in 3% of this series and in less than 1% of cases in the literature. Evidence of hepatic phospholipidosis and the development of pseudoalcoholic liver injury is most likely due to the biochemical effects of the drug and to possible metabolic idiosyncrasy, respectively. Serial blood enzyme measurements, as recommended by the manufacturer, may offer some protection against the development of more serious liver injury. However, levels of amiodarone may persist in various tissues for weeks to months following withdrawal, and stopping the drug does not guarantee the prompt reversal of any organ toxicity. Accordingly, the risks posed and benefits offered by amiodarone should be carefully weighed prior to discontinuing the drug, as the risk of sudden cardiac death may outweigh the hazards of ongoing hepatic, pulmonary or other toxicity.