Neuropathy and fatal hepatitis in a patient receiving amiodarone

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 neurotoxicity

PURPOSE

A case of amiodarone-induced neurotoxicity is reported.

SUMMARY

A 76-year-old man arrived at the emergency department with complaints of increasing imbalance over the past 2.5 months after a recent discharge from the hospital. He reported that his balance had worsened over the past week and that he now must use a cane to walk. His medical history included coronary artery disease, peripheral vascular disease, hypertension, hyperlipidemia, and paroxysmal atrial fibrillation. Home medications included enteric-coated aspirin 325 mg orally daily, isosorbide dinitrate 20 mg orally twice daily, amiodarone hydrochloride 400 mg orally three times daily, hydralazine hydrochloride 10 mg orally four times daily, extended-release metoprolol succinate 142.5 mg (equivalent to metoprolol tartrate 150 mg) orally daily, simvastatin 80 mg orally daily, and warfarin sodium 2.5 mg orally daily. Physical examination of the patient revealed finger-to-nose dysmetria, unsteady gait with leftward prevalence, positive Romberg's sign, and inability to perform heel-to-toe walk. All radiographic imaging studies and laboratory test values ruled out acute pathologies, bleeding, masses, and ischemia. As there were no physiological findings for the patient's symptoms and after careful evaluation of the patient's drug regimen, the patient's amiodarone was discontinued. His ataxia began to slowly improve. All neurologic symptoms resolved completely five months after discontinuation of amiodarone.

CONCLUSION

A 76-year-old man developed ataxia after taking amiodarone hydrochloride 400 mg orally three times daily for more than two months; the regimen was the intended loading dosage. The ataxia lessened over the first two weeks after the amiodarone was discontinued and resolved completely within five months after drug discontinuation.

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.

Causality assessment of liver injury after chronic oral amiodarone intake

BACKGROUND/AIM

The number of patients receiving amiodarone will increase in future years. As clinically significant hepatotoxicity associated with oral amiodarone is infrequent and difficult to predict, a new Bayesian-developed model is proposed to help in the causality assessment of amiodarone-induced liver injury.

METHODS

Incidence of abnormal liver enzymes in patients receiving amiodarone was obtained from placebo controlled clinical trials. Published case reports of amiodarone-induced hepatotoxicity were identified through a literature search. Maximum number of expected hepatotoxicity cases in amiodarone and placebo-treated patients was calculated using Poisson distribution. The calculated odds ratio was used as a Prior Odds (PrO) to subsequent quantification, using a Bayesian-approach, of individual amiodarone-induced hepatotoxicity likelihood.

RESULTS

PrO of amiodarone-induced hepatotoxicity was 0.48. Thirty nine amiodarone-associated hepatotoxicity case reports were retrieved. Half of published case reports developed an irreversible damage. The amiodarone Bayesian model combining information about latency period and period of remission, together with analytical parameters properly defines the toxicity profile shown in published case reports. The analytical pattern defined by this model is different from the one expected if liver injury in published cases was caused by other etiologies.

CONCLUSIONS

A method based on a Bayesian-approach, which links information from clinical trials with clinical hepatotoxicity profile from published case reports can be a useful tool for amiodarone-induced liver injury causality assessment. At present, this method is limited due to scarcity and quality of available data. Further efforts are needed to improve model ability in order to identify amiodarone-induced liver injury.

Hepatotoxicity of amiodarone

Amiodarone has proved very effective in the treatment of otherwise resistant cardiac tachyarrhythmias. The use of amiodarone has, however, been limited due to its serious side-effects. A patient with cholestatic hepatitis due to amiodarone treatment is presented below and a review of the hepatotoxicity of amiodarone is given. It is concluded that solid evidence exists of hepatic injury due to amiodarone treatment, including steatosis, alterations resembling alcoholic hepatitis, cholestatic hepatitis and micronodular cirrhosis of the liver. Patients receiving amiodarone should be regularly screened with respect to hepatic enzyme levels. Therapy should be discontinued on the suspicion of cholestatic injury or hepatomegaly.

Drug-induced phospholipidosis: issues and future directions

Numerous drugs containing a cationic amphiphilic structure are capable of inducing phospholipidosis in cells under conditions of in vivo administration or ex vivo incubation. The principal characteristics of this condition include the reversible accumulation of polar phospholipids in association with the development of unicentric or multicentric lamellated bodies within cells. There is an abundance of data providing an understanding of potential mechanisms for the induction of phospholipidosis; however, the process is likely to be complex and may differ from one drug to another. The functional consequences of the presence of this condition on cellular or tissue function are not well understood. The general consensus is that the condition is an adaptive response rather than a toxicological manifestation; however, additional studies to examine this question are needed. Until this issue is resolved, concerns about phospholipidosis will continue to exist at regulatory agencies. Procedures for the screening of potential phospholipogenic candidate compounds are available. In contrast, a clear need exists for the identification of valid biomarkers to assess the development of phospholipidosis in preclinical and clinical studies.

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.

Hépatotoxicité de l'amiodarone à propos de deux observations et revue de la littérature

INTRODUCTION

Amiodarone can induced hepatic dysfunction.

OBSERVATIONS

We describe two patients who developed hepatotoxicity presenting suggestive histological features. The outcome was fatal in one case but lesions were reversible in the second case upon treatment interruption.

CONCLUSION

These observations show the necessity of hepatic monitoring of patients treated with amiodarone in order to detect potentially severe hepatotoxicity.

Drug-induced phospholipidosis: are there functional consequences?

Phospholipidosis induced by drugs with a cationic amphiphilic structure is a generalized condition in humans and animals that is characterized by an intracellular accumulation of phospholipids and the concurrent development of concentric lamellar bodies. The primary mechanism responsible for the development of phospholipidosis is an inhibition of lysosomal phospholipase activity by the drugs. While the biochemical and ultrastructural features of the condition have been well characterized, much less effort has been directed toward understanding whether the condition has adverse effects on the organism. While there are a few cationic amphiphilic drugs that have been reported to cause phospholipidosis in humans, the principal concern with this condition is in the pharmaceutical industry during preclinical testing. While this class of drugs should technically be referred to as cationic lipophilic, the term cationic amphiphilic is widely used and recognized in this field, and for this reason, the terminology cationic amphiphilic drugs (CADs) will be employed in this Minireview. The aim of this Minireview is to provide an evaluation of the state of knowledge on the functional consequences of CAD-induced phospholipidosis.

Severe intrahepatic cholestasis caused by amiodarone toxicity after withdrawal of the drug: a case report and review of the literature

Cholestasis has been reported as a rare presentation among patients with severe liver injury secondary to amiodarone hepatic toxicity. We report an unusual case of amiodarone-induced cholestatic hepatotoxicity occurring after amiodarone had been discontinued and the initial abnormal liver function findings had improved. The patient, without jaundice at the initial presentation, developed severe jaundice about 4 months after withdrawal of amiodarone. Light and transmission electron microscopic examination of a specimen secured by computed tomographically guided liver biopsy was consistent with amiodarone hepatic toxicity as the cause of intrahepatic cholestasis. An abdominal ultrasound, endoscopic retrograde cholangiography, and dimethyl iminodiacetic acid and computed tomographic scans of the abdomen all failed to demonstrate any other causes for jaundice other than amiodarone toxicity. Thus, amiodarone hepatic toxicity may occur after drug withdrawal even if results of liver function tests improve. Histopathologic examination of a liver biopsy specimen is of value for diagnosis and prognosis. The liver biopsy findings, clinical course, and liver function test results are discussed, and the English-language literature on amiodarone cholestatic hepatotoxicity is reviewed.

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.

Effects of short-term and long-term administration of amiodarone on hepatobiliary function in male rats

Functional, biochemical and histological parameters of hepatotoxicity were assessed in male Sprague-Dawley rats receiving amiodarone (Am) short-term by gavage (5, 50, 150 and 500 mg Am kg-1 day-1, 10 days) or dietary exposure (50 ppm, 1500 ppm, 4-week duration), or by long-term dietary exposure (50 ppm, 8-month duration). Serum enzyme (ALT, AST, ICD) levels and histopathological examination indicated no observable evidence of toxicity among rats of any of the treatment groups. Reduced food intake and reduction in weight gain was observed for rats exposed short-term to 1500 ppm dietary Am. Assessment of hepatobiliary function in treated rats indicated that short-term and long-term dietary exposure to Am resulted in a compromised excretion of readily excretable phenolphthalein glucuronide (PG), although inanition may account for this effect in the 1500 ppm group. Rats receiving Am by gavage exhibited a reduction in biliary excretion of PG, which was not dose-dependent. Distribution of Am and its major metabolite, desethylamiodarone, was similar to previous reports wherein both compounds accumulated in adipose, lung and liver tissue. These data suggest that minor alterations of hepatobiliary function occur in the absence of histological alterations and may preceed biochemical changes, as assessed in this study.

[Amiodarone-induced hepatitis: biological, histological diagnosis, development and role of associated factors. Review of the literature. Report of 2 cases]

Two cases of pseudo-alcoholic amiodarone-induced hepatitis are reported. The authors mention the different clinical forms of the disease and describe its clinical, biochemical and histological features. They stress the unpredictable and discordant character of its course and the influence of associated pathological factors. The role played by Ito's cells in the genesis of the liver fibrosis observed in amiodarone toxicity is discussed.

Drug-induced liver disease

The relative importance of drug-induced liver disease assumes much significance in certain groups of patients such as the elderly. The majority of cases occur as unexpected reactions to a therapeutic dose of a drug. Factors affecting susceptibility to drug-induced liver disease are diverse and are discussed in this article.

A general overview of amiodarone toxicity: its prevention, detection, and management

Although amiodarone is a highly effective antiarrhythmic agent, it has a high incidence of side effects, some of which can be serious or even lethal. With close monitoring, side effects can be found in essentially all patients, but fortunately most of these are mild and well tolerated. Furthermore, many will respond to dosage reduction in a relatively short period of time, ie, days to weeks, which is remarkable considering the long period of time amiodarone has been shown to persist in tissues. There is reasonable evidence that toxicity, particularly the early toxic manifestations with large loading dosages, can be favorably modified by reducing the dosage. Similarly, reducing the maintenance dosage will, in most instances, reduce or eliminate most toxic manifestations. The mechanisms of toxic effects are uncertain, but suggestive evidence exists for and against both an immunologic reaction and an intracellular lysosomal lipoidosis. Principles of use of amiodarone should include individualizing administration of dosages for each patient due to the unusual pharmacokinetic properties of this drug and continuous long-term attempts at using the lowest effective dosage. There are no definite tests that predict amiodarone efficacy or toxicity, but the serum level can be used as a rough guide of absorption and distribution in the attempt to minimize the maintenance dosage. No guidelines regarding screening tests for toxicity can be made at this time since great variability in these tests has been reported, and no evidence exists for their benefit in preventing adverse effects to amiodarone. However, follow-up testing at the intervals noted in the package insert are reasonable and important. The possibility of interactions with drugs already reported and with others not yet reported should always be kept in mind, and appropriate monitoring for clinical evidence of toxicity due to the concomitantly used drugs should be undertaken. Amiodarone can have a tremendous beneficial effect in the proper circumstances, but it is a drug that should command utmost respect because of its side effects and requires constant vigilance from any physician wishing to use it.

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.

Hepatotoxicity associated with amiodarone therapy

Amiodarone has been reported to cause asymptomatic increases in liver function tests in 15-55% of patients. Clinically apparent, symptomatic hepatic disease occurs less frequently, but patients have been reported to have hepatomegaly, jaundice, cirrhosis, or chronic active hepatitis. Less well recognized is the fact that amiodarone has been attributed to six deaths. We cared for a patient with amiodarone hepatotoxicity, which led us to review the literature associated with this serious condition.

Anti-amiodarone antibodies: detection and relationship to the development of side effects

PURPOSE

It has become evident in the past few years that amiodarone, a powerful antiarrhythmic agent, induces considerable side effects. These may be due to an amiodarone-elicited lipid storage disease and to the iodine content of amiodarone, but might also be causally related to amiodarone-induced immune reactions. The latter possibility prompted us to develop a sensitive anti-amiodarone antibody detection assay based on the immunodot technique.

PATIENTS AND METHODS

Sera were obtained from 10 untreated control subjects and 33 patients receiving amiodarone. Using serum dilutions of 1:500 and 1:1,000, the lower detection limit was 0.3 microgram/ml of anti-amiodarone antibodies as calculated from a simultaneously performed IgG standard curve.

RESULTS

Screening of sera from the untreated control subjects and amiodarone-treated patients revealed that the untreated subjects had no anti-amiodarone antibodies, that only one of 16 patients without clinical side effects had elevated anti-amiodarone antibodies, but that seven of 12 patients with amiodarone-induced thyroid disease and four of five patients with other side effects had elevated anti-amiodarone antibody titers (1.2 to 2.5 micrograms/ml). The combined evaluation of anti-amiodarone antibody titers and cumulative dose was found to be a highly reliable indicator of side effects, as all patients with more than 100-g cumulative dose of amiodarone and more than 0.6 microgram/ml of anti-amiodarone antibodies had side effects.

CONCLUSION

The detection of anti-amiodarone antibodies in patients with amiodarone-elicited side effects underscores the possible contribution of immunologic reactions to the development of certain side effects.

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

Morphological and biochemical investigations were performed in guinea pigs after 1, 3, 5 and 16 weeks of amiodarone feeding. The most prominent morphological finding was an increase in dense bodies in hepatocytes, Kupffer cells and in bile duct epithelia, reaching a maximum after 5 weeks of treatment according to morphometric analysis. Similar time courses were observed for the serum and liver tissue concentrations of amiodarone and desethylamiodarone and the--albeit minimal--extent of hepatocellular necrosis. Phospholipids in the liver homogenate were unchanged after 1 week, but significantly increased after prolonged amiodarone treatment. There was no significant alteration in the pattern of individual phospholipids. Serum and tissue concentrations as well as the extent of phospholipidosis do not appear to be a function of the duration of drug application. A very close correlation, however, was observed between the liver tissue concentration of amiodarone and the amount of dense bodies as a morphological expression of phospholipidosis.

Amiodarone induced phospholipidosis. Biochemical, morphological and functional changes in the lungs of rats chronically treated with amiodarone

Amiodarone, an antiarrhythmic drug, causes pulmonary fibrosis in some patients during chronic treatment but the mechanism is unknown. We studied the effects of amiodarone on pulmonary biochemistry, morphology and function at doses of 25 and 50 mg/kg/12 hr given to rats by gavage for four weeks. Plasma and pulmonary phospholipids were significantly augmented, 13% and 88% respectively, in the group given amiodarone 50 mg/kg/12 hr compared to pair-fed controls. Typical phospholipidosis-like light and electron microscopic alterations were seen in the lung, their severity related to the extent of biochemical changes induced by amiodarone. Pulmonary function tests revealed mild but not significant changes in O2 and CO2 alveolar exchange efficiency and lung compliance (P-V curve) of treated animals in comparison to pair fed controls. Plasma average concentrations of amiodarone and its main metabolite, desethylamiodarone, after four weeks were 2.46 +/- 0.18 and 0.73 +/- 0.13 micrograms/ml, respectively, in the 50 mg/kg/12 hr group. In the same group amiodarone and desethylamiodarone concentrations in lung were 163 +/- 26 and 569 +/- 153 times higher than those in plasma. A highly significant correlation was found between amiodarone concentrations in plasma and lung and phospholipid content in the lung. A subgroup of animals received amiodarone 50 mg/kg/12 hr for 8 weeks. The pulmonary phospholipidosis-like lesions were similar to those observed after one month of treatment, no fibrosis was evident on light microscopic examination.

Granular cells as a marker of early amiodarone hepatotoxicity: a pathological and analytical study

Two contrasting cases of amiodarone hepatotoxicity are described. In one, perivenular collections of swollen cells, probably macrophages, with granular cytoplasm in an otherwise nearly normal liver were observed. Transmission electron microscopy showed that the cytoplasmic granularity was due to lysosomal bodies of various sizes. X-ray energy and wavelength spectroscopic analysis showed a high iodine content in these lysosomal bodies, good presumptive evidence of the presence of amiodarone or one of its metabolites. In the second case there was a micronodular cirrhosis, and similar granular cells also containing iodine were seen in the fibrous connective tissue. These cases seem to represent the very early and late stages of amiodarone hepatotoxicity. In a patient taking this drug aggregates of swollen granular cells may be a sensitive and histopathologically useful marker of early amiodarone toxicity.

Bronchoalveolar lavage in amiodarone pneumonitis. Cellular abnormalities and their relevance to pathogenesis

To investigate the contribution of direct cytotoxicity and immune-mediated hypersensitivity to the pathogenesis of amiodarone pneumonitis, we evaluated cells recovered by bronchoalveolar lavage from 13 patients with amiodarone pneumonitis. Alveolar macrophages from all patients contained two types of abnormal inclusions: small clear vacuoles and large phagolysosomes containing phospholipid in lamellar structures, abnormalities previously attributed to direct cytotoxicity from amiodarone. However, these changes were always associated with abnormalities in the numbers and types of immune and inflammatory cells present in the lower respiratory tract, which closely resemble those seen in hypersensitivity pneumonitis associated with inhaled antigens. Following discontinuation of amiodarone and institution of corticosteroid therapy, clinical improvement correlated with a return toward normal in the pattern of inflammatory cells present in the lung, although alveolar macrophages continued to display evidence of drug-induced cytotoxicity. These findings support the possibility that a cell-mediated immune response usually plays a role in the pathogenesis of amiodarone pneumonitis, although direct cytotoxicity may predispose these patients to the development of this abnormal immune response.

Chronic liver disease after low daily doses of amiodarone. Report of three cases

A few cases of alcohol-like chronic liver disease have recently been described in patients on high daily doses of amiodarone (400-600 mg) for 5-24 months. We report here 3 cases in which similar lesions were observed after low daily doses of amiodarone. Daily dosage was 200 mg in 2 cases, 400 mg then 200 mg in the third one, and duration of therapy ranged between 36 and 60 months. Symptomatology was limited to hepatomegaly and/or mild elevation of serum aminotransferases. Liver biopsy showed alcohol-like lesions with fibrosis in 2 cases and cirrhosis in 1 case. Electron microscopy disclosed hepatic phospholipidosis. These cases indicate that chronic liver disease may be observed even when amiodarone is prescribed at low daily dosage, provided that duration of treatment is long. They also suggest that rather than the daily dosage, the cumulative dose of amiodarone is a major factor in the development of hepatic injury.

Amiodarone and its desethyl metabolite: tissue distribution and morphologic changes during long-term therapy

The pharmacokinetic characteristics of amiodarone suggest extensive tissue deposition. We confirmed this by measuring tissue concentrations of the drug and of its major metabolite, desethylamiodarone, in human tissues. These were obtained at autopsy (n = 9), surgery (n = 7), or biopsy (n = 2) from 18 patients who had been treated with amiodarone for varying periods of time. High concentrations of amiodarone were found in fat (316 mg/kg wet weight in autopsy specimens, 344 mg/kg wet weight in biopsy specimens). Amiodarone and desethylamiodarone concentrations (mg/kg wet weight, autopsy samples) were also high in liver (391 and 2354), lung (198 and 952), adrenal gland (137 and 437), testis (89 and 470), and lymph node (83 and 316). We also found high concentrations of amiodarone (306 mg/kg wet weight) and desethylamiodarone (943 mg/kg wet weight) in abnormally pigmented ("blue") skin from patients with amiodarone-induced skin pigmentation. These values were 10-fold higher than those in unpigmented skin from the same patients. These high concentrations were associated with lysosomal inclusion bodies in dermal macrophages in the pigmented skin. The inclusion bodies were intrinsically electron dense and were shown to contain iodine by energy dispersive x-ray microanalysis. Lysosomal inclusion bodies shown by electron microscopy to be multilamellar were seen in other tissues. These tissues included terminal nerve fibers in pigmented skin, pulmonary macrophages, blood neutrophils, and hepatocytes and Kupffer cells. These characteristic ultrastructural findings occur in both genetic lipidoses and lipidoses induced by other drugs, e.g., perhexiline. We conclude that during therapy with amiodarone, widespread deposition of amiodarone and desethylamiodarone occurs. This leads to ultrastructural changes typical of a lipidosis. These changes are seen clearly in tissues associated with the unwanted effects of amiodarone, e.g., skin, liver and lung.

Peripheral neuropathy during longterm high-dose amiodarone therapy

Three patients developed peripheral neuropathy after taking amiodarone for more than 18 months. All had high serum concentrations of amiodarone and its desethyl metabolite; in one patient concentrations in a sural nerve biopsy were 80 times higher than in serum. Peripheral neuropathy is a complication of large doses of amiodarone taken over long periods.