Amiodarone

The diagnostic utility of chest computed tomography scoring for the assessment of amiodarone-induced pulmonary toxicity

BACKGROUND/AIMS

Amiodarone is one of the most widely used antiarrhythmic agents; however, amiodarone-induced pulmonary toxicity (APT) can be irreversible and sometimes fatal. The aim of this study was to evaluate the feasibility of chest computed tomography (CT) as a diagnostic tool for APT and to assess the utility of the CT APT score as an index for predicting the severity of APT.

METHODS

Patients underwent amiodarone treatment for various reasons, most often atrial fibrillation, for more than 2 years, and those that received a cumulative dose > 100 g were enrolled. A total of 34 patients who underwent chest CT between December 2011 and June 2012 were enrolled, whether or not they had clinical symptoms. The APT CT score was defined as the number of involved regions in the lung, which was divided into 18 regions (right and left, upper, middle, and lower, and central, middle, and peripheral). The CT findings were evaluated according to the total dose and duration of amiodarone treatment and the results of a pulmonary function test. Clinical symptoms and outcomes were also evaluated according to APT CT scores.

RESULTS

Seven patients had positive APT CT scores (interstitial fibrosis in five, organizing pneumonia in one, and mixed interstitial fibrosis and organizing pneumonia in one), and these patients exhibited significantly lower diffusion capacity for carbon monoxide in the lungs compared with patients without an increased APT CT score (70.2% ± 6.9% vs. 89.7% ± 19.4%; p = 0.011). Three of the seven patients experienced overt APT that required hospital admission.

CONCLUSIONS

Chest CT is a useful diagnostic tool for APT, and the APT CT score might be a useful index for assessing the severity of APT.

Pharmacokinetic and pharmacodynamic profile of dronedarone , a new antiarrhythmic agent for the treatment of atrial fibrillation

INTRODUCTION

Atrial fibrillation (AF) is the most common arrhythmia and is associated with increased morbidity and mortality. Dronedarone is a recent antiarrhythmic drug that has been developed for treatment of AF, with electrophysiological properties similar to amiodarone but with a lower incidence of side effects.

AREAS COVERED

This review evaluates the efficacy, safety, tolerability and side effects of dronedarone in the treatment of AF. In particular, the review includes studies comparing: dronedarone and placebo (ANDROMEDA, ATHENA, DAFNE, ERATO, EURIDIS/ADONIS, HESTIA, PALLAS trials), dronedarone and amiodarone (DIONYSOS trial), ranolazine and dronedarone given alone and in combination (HARMONY trial).

EXPERT OPINION

Dronedarone is an interesting antiarrhythmic agent in well-selected groups of patients. It also has several other pleiotropic effects that may potentially be beneficial in clinical practice, such as the reduction of the risk of stroke and acute coronary syndromes. In addition, combination therapies such as those with dronedarone and ranolazine, currently being investigated in the HARMONY trial, may provide another interesting approach to increase the antiarrhythmic efficacy and further reduce the incidence of side effects. A better understanding of the mechanisms underlying dronedarone's pleiotropic actions is expected to facilitate the selection of patients benefiting from dronedarone, as well as the development of novel antiarrhythmic drugs for AF.

A systematic assessment of mitochondrial function identified novel signatures for drug-induced mitochondrial disruption in cells

Mitochondrial perturbation has been recognized as a contributing factor to various drug-induced organ toxicities. To address this issue, we developed a high-throughput flow cytometry-based mitochondrial signaling assay to systematically investigate mitochondrial/cellular parameters known to be directly impacted by mitochondrial dysfunction: mitochondrial membrane potential (MMP), mitochondrial reactive oxygen species (ROS), intracellular reduced glutathione (GSH) level, and cell viability. Modulation of these parameters by a training set of compounds, comprised of established mitochondrial poisons and 60 marketed drugs (30 nM to 1mM), was tested in HL-60 cells (a human pro-myelocytic leukemia cell line) cultured in either glucose-supplemented (GSM) or glucose-free (containing galactose/glutamine; GFM) RPMI-1640 media. Post-hoc bio-informatic analyses of IC50 or EC50 values for all parameters tested revealed that MMP depolarization in HL-60 cells cultured in GSM was the most reliable parameter for determining mitochondrial dysfunction in these cells. Disruptors of mitochondrial function depolarized MMP at concentrations lower than those that caused loss of cell viability, especially in cells cultured in GSM; cellular GSH levels correlated more closely to loss of viability in vitro. Some mitochondrial respiratory chain inhibitors increased mitochondrial ROS generation; however, measuring an increase in ROS alone was not sufficient to identify mitochondrial disruptors. Furthermore, hierarchical cluster analysis of all measured parameters provided confirmation that MMP depletion, without loss of cell viability, was the key signature for identifying mitochondrial disruptors. Subsequent classification of compounds based on ratios of IC50s of cell viability:MMP determined that this parameter is the most critical indicator of mitochondrial health in cells and provides a powerful tool to predict whether novel small molecule entities possess this liability.

From the radiologic pathology archives: organization and fibrosis as a response to lung injury in diffuse alveolar damage, organizing pneumonia, and acute fibrinous and organizing pneumonia

Organization, characterized by fibroblast proliferation, is a common and nearly universal response to lung injury whether it is focal or diffuse. Despite the vast range of injurious agents, the lung's response to injury is quite limited, with a similar pattern of reaction seen radiologically and histologically regardless of the underlying cause. Although there is a tendency to divide organization into distinct entities, the underlying injury to the alveolar epithelial basement membrane is a uniting factor in these processes. This pattern of lung injury is seen in the organizing phase of diffuse alveolar damage, organizing pneumonia (OP), acute fibrinous and organizing pneumonia, and certain types of fibrotic lung disease. In addition, although organization can heal without significant injury, in some instances it progresses to fibrosis, which can be severe. When fibrosis due to organization is present, other histologic and imaging patterns, such as those seen in nonspecific interstitial pneumonia, can develop, reflecting that fibrosis can be a sequela of organization. This article reviews the histologic and radiologic findings of organization in lung injury due to diffuse alveolar damage, OP, and acute fibrinous and organizing pneumonia and helps radiologists understand that the histologic and radiologic findings depend on the degree of injury and the subsequent healing response.

Temsirolimus induces surfactant lipid accumulation and lung inflammation in mice

Interstitial lung disease (ILD) is a well-known adverse effect of mammalian target of rapamycin (mTOR) inhibitors. However, it remains unknown how lung toxicities are induced by mTOR inhibitors. Here, we constructed a mouse model of mTOR inhibitor-induced ILD using temsirolimus and examined the pathogenesis of the disease. Male ICR mice were treated with an intraperitoneal injection of different doses of temsirolimus (3 or 30 mg·kg−1·wk−1) or vehicle. Temsirolimus treatment increased capillary-alveolar permeability and induced neutrophil infiltration and fibrinous exudate into the alveolar space, indicating alveolar epithelial and/or endothelial injury. It also induced macrophage depletion and the accumulation of excessive surfactant phospholipids and cholesterols. Alveolar macrophage depletion is thought to cause surfactant lipid accumulation. To further examine whether temsirolimus has cytotoxic and/or cytostatic effects on alveolar macrophages and alveolar epithelial cells, we performed in vitro experiments. Temsirolimus inhibited cell proliferation and viability in both alveolar macrophage and alveolar epithelial cells. Temsirolimus treatment caused some signs of pulmonary inflammation, including upregulated expression of several proinflammatory cytokines in both bronchoalveolar lavage cells and lung homogenates, and an increase in lymphocytes in the bronchoalveolar lavage fluid. These findings indicate that temsirolimus has the potential to induce alveolar epithelial injury and to deplete alveolar macrophages followed by surfactant lipid accumulation, resulting in pulmonary inflammation. This is the first study to focus on the pathogenesis of mTOR inhibitor-induced ILD using an animal model.

A Novel Amiodarone-Eluting Biological Glue for Reducing Postoperative Atrial Fibrillation

Objective:

Postoperative atrial fibrillation (POAF) is the most common complication after cardiac surgery, leading to increased morbidity and mortality. The aim of this preliminary study was to evaluate a novel drug delivery system for local release of amiodarone.

Methods:

In the current prospective study, 9 goats underwent attachment of right atrial (RA) epicardial electrodes. Alginate-based glue with amiodarone was applied to the RA of the treatment groups. Rapid atrial response (RAR) to burst pacing was assessed before application and in the third postoperative day (POD3). Average RAR frequency was defined as the average percentage of inductions resulting in RAR per animal. Myocardial and extracardiac tissue amiodarone concentrations were analyzed.

Results:

Differences in RAR proportions between baseline and POD3 were greater in the treatment group versus the control group ( P = .034). Average RAR frequency was reduced by 34% in the treatment group (baseline: 65%; POD3: 31%), while it was increased by 11.3% in the control (baseline:43.8%; POD3: 55%). The treatment group demonstrated a greater proportion of animals meeting the success criterion of net percentage reduction in RAR frequency greater than 25% ( P = .047). The average amount of total amiodarone detected in the RA was 104.4 ± 28.9 µg; the transmural concentration was linearly distributed ( P < .0001). Extracardiac tissue concentrations were below the detection level.

Conclusions:

Local alginate-based amiodarone delivery demonstrated an RAR frequency reduction of clinical importance in response to burst pacing. The electrophysiological response was achieved while maintaining below-detection systemic drug levels. Current findings may point to the system’s future applicability in reducing POAF risk in humans.

Initial characteristics and outcome of hospitalized patients with amiodarone pulmonary toxicity

Amiodarone-induced pulmonary toxicity (APT) is a serious adverse event that can lead to death. The aims of our study are to determine factors associated with mortality and to describe outcome and sequelae of patients with APT.

METHODS

Forty-six patients with APT were divided into two groups according to survival at day 90 for a clinical, functional, biological and radiological comparaison. We then evaluated the evolution of 15 survivors at a median of three months [1-6 months] and/or 12 months [8-36 months].

RESULTS

Mortality of APT at day 90 was 37% (17 patients) and was linked to the speed of onset of symptoms and a high HRCT alveolar score. Angiotensin system antagonist treatment was prescribed significantly more in the survival group (p = 0.042, HR 0.34 (95% CI 0.12-0.96)). In surviving patients, dyspnea, vital capacity and HRCT alveolar score improved significantly while HRCT fibrosis score deteriorated gradually during the first six months. At the end of the study, all the surviving patients presented functional and/or radiological sequelae.

CONCLUSIONS

Severity of APT is linked to the extent and speed of onset of pulmonary damage. After the initial episode, the patients who survived improved slowly but with persistent sequelae.

Bortezomib therapy-related lung disease in Japanese patients with multiple myeloma: incidence, mortality and clinical characterization

Because of the potentially high mortality rate (6.5%) associated with bortezomib-induced lung disease (BILD) in Japanese patients with relapsed or refractory multiple myeloma, we evaluated the incidence, mortality and clinical features of BILD in a Japanese population. This study was conducted under the Risk Minimization Action Plan (RMAP), which was collaboratively developed by the pharmaceutical industry and public health authority. The RMAP consisted of an intensive dissemination of risk information and a recommended countermeasure to health-care professionals. All patients treated with bortezomib were consecutively registered in the study within 1 year and monitored for emerging BILD. Of the 1010 patients registered, 45 (4.5%) developed BILD, 5 (0.50%) of whom had fatal cases. The median time to BILD onset from the first bortezomib dose was 14.5 days, and most of the patients responded well to corticosteroid therapy. A retrospective review by the Lung Injury Medical Expert Panel revealed that the types with capillary leak syndrome and hypoxia without infiltrative shadows were uniquely and frequently observed in patients with BILD compared with those with conditions associated with other molecular-targeted anticancer drugs. The incidence rate of BILD in Japan remains high compared with that reported in other countries, but the incidence and mortality rates are lower than expected before the introduction of bortezomib in Japan. This study describes the radiographic pattern and clinical characterization of BILD in the Japanese population. The RMAP seemed clinically effective in minimizing the BILD risk among our Japanese population.

Bronchiolitis: adopting a unifying definition and a comprehensive etiological classification

Bronchiolitis is an inflammatory and potentially fibrosing condition affecting mainly the intralobular conducting and transitional small airways. Secondary bronchiolitis participates in disease process of the airways and/or the surrounding lobular structures in the setting of several already defined clinical entities, mostly of known etiology, and occurs commonly. Primary or idiopathic bronchiolitis dominates and characterizes distinct clinical entities, all of unknown etiology, and occurs rarely. Secondary bronchiolitis regards infections, hypersensitivity disorders, the whole spectrum of smoking-related disorders, toxic fumes and gas inhalation, chronic aspiration, particle inhalation, drug-induced bronchiolar toxicities, sarcoidosis and neoplasms. Idiopathic or primary bronchiolitis defines clinicopathologic entities sufficiently different to be designated as separate disease entities and include cryptogenic constrictive bronchiolitis, diffuse panbronchiolitis, diffuse idiopathic pulmonary neuroendocrine cell hyperplasia, neuroendocrine hyperplasia in infants, bronchiolitis obliterans syndrome in lung and allogeneic hematopoietic cell transplantation, connective tissue disorders, inflammatory bowel disease and bronchiolitis obliterans organizing pneumonia. Most of the above are pathological descriptions used as clinical diagnosis. Acute bronchiolitis, though potentially life threatening, usually regresses. Any etiology chronic bronchiolitis contributes to morbidity and/or mortality if it persists and/or progresses to diffuse airway narrowing and distortion or complete obliteration. Bronchiolitis in specific settings leads to bronchiolectasis, resulting in bronchiectasis.

Risk of Cardiovascular Events, Stroke, Congestive Heart Failure, Interstitial Lung Disease, and Acute Liver Injury: Dronedarone versus Amiodarone and Other Antiarrhythmics

No published studies have evaluated the risks of cardiovascular (CV) events, stroke, congestive heart failure (CHF), interstitial lung disease (ILD), and severe acute liver injury (ALI) related to antiarrhythmics treatment in real-world clinical practice setting. We examined the relationship between the above events and the selected antiarrhythmics in the real-world setting in the US. Using a retrospective cohort design, the hazard ratios of the outcome events were analyzed from 10,455 adult patients with a diagnosis of atrial fibrillation/atrial flutter and a new treatment with dronedarone (comparison drug), amiodarone, sotalol, flecainide, or propafenone between 07/20/2009 and 12/31/2010 from the Clinformatics Data MartTM database. The patients were followed until: 1) switch to another antiarrhythmic drug, 2) occurrence of the outcome event, 3) end of enrollment, or 4) end of the study period, whichever occurred first. No significant differences were observed in the hazard ratios of the outcome events between dronedarone, amiodarone, and the other antiarrhythmics, except that amiodarone was associated with a higher risk of CV events (adjusted HR = 1.7, 95%CI: 1.1-2.4) and stroke (adjusted HR = 2.0, 95%CI: 1.33.2), compared to dronedarone, especially amongst patients without a CHF history (adjusted HR = 2.4, 95%CI: 1.4-3.8 and 2.2, 95%CI: 1.23.9). A higher risk of CHF was also associated with amiodarone in patients without history of CHF at baseline (adjusted HR = 2.7, 95%CI: 2.03.6). In this real-world investigation, no difference in risk was observed between dronedarone, sotalol, and propafenone initiators for CV events, stroke, CHF, ILD, and ALI. Amiodarone was associated with higher risks of CV events, stroke, and CHF than dronedarone in patients without a CHF history, indicating dronedarone could be an alternative therapy option with lower risk of CV events than amiodarone for the above patients.

Effect of stem cell therapy on amiodarone induced fibrosing interstitial lung disease in albino rat

BACKGROUND AND OBJECTIVES

The fibrosing forms of interstitial lung disease (ILD) are associated with significant morbidity and mortality. ILD may be idiopathic, secondary to occupational, infection, complicate rheumatic diseases or drug induced. Efficacy of antifibrotic agents is as far as, limited and uncertain. No effective treatment was confirmed for pulmonary fibrosis except lung transplantation. The present study aimed at investigating the possible effect of human cord blood mesenchymal stem cell (MSC) therapy on fibrosing ILD. This was accomplished by using amiodarone as a model of induced lung damage in albino rat.

METHODS AND RESULTS

Seventeen adult male albino rats were divided into 3 groups. Rats of amiodarone group were given 30 mg/kg of amiodarone orally 6 days/ week for 6 weeks. Rats of stem cell therapy group were injected with stem cells in the tail vein following confirmation of lung damage and left for 4 weeks before sacrifice. Obstructed bronchioles, thickened interalveolar septa and thickened wall of pulmonary vessels were found and proved morphometrically. Reduced type I pneumocytes and increased area% of collagen fibers were recorded. All findings regressed on stem cell therapy.

CONCLUSIONS

Cord blood MSC therapy proved definite amelioration of fibrosing interstitial lung disease provided therapy starts early in the development of the pathogenesis.

Very early onset of amiodarone-induced pulmonary toxicity

Amiodarone is a widely used antiarrhythmic agent. Among its various adverse effects, amiodarone-induced pulmonary toxicity (APT) is the most life threatening complication, which has been described mostly in patients who have been in treatment with high accumulative doses for a long duration of time. However, amiodarone therapy in short-term duration induced APT was rarely reported. We describe a case of a 54-year-old man who is presented with symptoms of APT after a few days of therapy for post-myocardial infarction ventricular tachycardia. For early diagnosis and successful treatment, awareness and high suspicion of this rare type of early onset APT is crucial in patients with amiodarone therapy.

Incidence and outcomes of bepridil-induced interstitial pneumonia

BACKGROUND

The incidence of bepridil-induced pulmonary toxicity, such as interstitial pneumonia, is still unknown. The aim of the present study was to evaluate the incidence of bepridil-induced pulmonary toxicity.

METHODS AND RESULTS

A total of 253 patients treated with bepridil between January 2009 and January 2011 were retrospectively evaluated. Eight out of the 222 evaluable patients (male/female: 5/3, age range: 64-97 years, average age: 80.5 years, median age: 81.0 years) showed bepridil-induced pulmonary toxicity.

CONCLUSIONS

The incidence of bepridil-induced pulmonary toxicity was 3.60% in our study population.

In vitro study on the pulmonary cytotoxicity of amiodarone

CONTEXT

Amiodarone (an iodinated benzofuran) is a Class III antiarrhythmic drug that produces significant pulmonary disease. Proposed mechanisms of this cytotoxicity include necrosis, apoptosis, mitochondrial dysfunction and glutathione depletion.

OBJECTIVE

This study was designed primarily to explore whether amiodarone impairs lung tissue cellular bioenergetics in BALB/c and Taylor Outbred mice.

MATERIALS AND METHODS

Cellular respiration (mitochondrial O2 consumption), ATP, caspase activity and glutathione were measured in lung fragments incubated in vitro with 22 µM amiodarone for several hours.

RESULTS

Without amiodarone, lung tissue cellular mitochondrial O2 consumption decayed exponentially with time, showing two distinct phases sharply separated at t ≥ 150 min. The rate of cellular respiration was 6-10-fold higher in the late phase compared to the early phase (p<0.0001). Lung tissue ATP also decayed exponentially with time, suggesting "uncoupling oxidative phosphorylation" was the responsible mechanism (low cellular ATP with high mitochondrial O2 consumption, resulting in rapid depletion of cellular metabolic fuels). Although intracellular caspase activity increased exponentially with time, the uncoupling was not prevented by the pancaspase inhibitor zVAD-fmk (N-benzyloxycarbonyl-val-ala-asp (O-methyl)-fluoromethylketone). The same profiles were noted in the presence of amiodarone; but cellular ATP decayed 50% faster. Cellular glutathione for untreated tissue was 560 ± 287 pmol mg(-1) (n=12) and for treated tissue was 490 ± 226 pmol mg(-1) (n=12, p=0.5106).

CONCLUSION

Uncoupling oxidative phosphorylation was demonstrated in untreated mouse lung tissues. Amiodarone lowered cellular ATP. Further studies are needed to explore the susceptibility of the lung to these deleterious insults and their relevance to human diseases.

Exogenous lipoid pneumonia caused by chronic improper use of baby body oil in adult patient

INTRODUCTION

Exogenous lipoid pneumonia (ELP) is an uncommon condition resulting from aspirating or inhaling fatlike material. These substances elicit a foreign body reaction and proliferative fibrosis in the lung.

CASE REPORT

We report a case of a 38-year-old woman with bilateral pulmonary infiltration. There were no clinical symptoms of this infiltration at diagnosis. The infiltration was found coincidentally during the pre-operation examination before surgery. A chest computed tomography scan revealed bilateral lung consolidation, particularly in the S6 area on the right side. The transthoracic lung biopsy led to suspicion of ELP. Precise anamnesis confirms the diagnosis of ELP caused by chronic improper use of baby body oil. Two years after discontinuing "baby body oil therapy", a chest CT scan revealed partial regression of pulmonary infiltration.

CONCLUSION

The diagnosis of exogenous lipoid pneumonia is often difficult as symptoms, signs, and radiographic findings are all rather non-specific. We would like to emphasize the role of precise case history in better identification of ELP.

Protective effects of neferine on amiodarone-induced pulmonary fibrosis in mice

The effects of neferine, a bisbenzylisoquinline alkaloid extracted from the Chinese traditional medicine seed embryo of Nelumbo nucifera Gaertn, on amiodarone-induced pulmonary fibrosis in mice were evaluated. Adult Kunming mice were induced to develop pulmonary fibrosis through intratracheal instillation of amiodarone (6.25 mg/kg) on the 1st, 3rd and 5th day. Mice were treated orally with saline, neferine (20 mg/kg), prednisolone (15 mg/kg), pirfenidone (100 mg/kg) twice a day after the third amiodarone instillation. On Day 21, all the lung tissues were collected for hydroxyproline measurement and the histological examination by hematoxylin-eosin and Masson staining. All the blood sample were collected for surfactant protein-D (SP-D) levels assay, Th1/Th2 balance valuation, CD4+CD25+ regulatory T cells (Tregs) analysis by Enzyme-linked immunosorbent assay and flow cytometry. Our data showed that neferine significantly restored the significant reductions in body weights, the increased levels of lung index and hydroxyproline, the abnormal histological findings, the serum SP-D increase, the Th1/Th2 imbalance by decreasing IL-4 and increasing IFN-γ levels and the increases in the population of CD4+CD25+ Tregs associated with amiodarone instillation in mice. Similar changes were also observed in the prednisolone or pirfenidone treated mice. In conclusion, these results indicated that neferine possessed a significant inhibitory effect on amiodarone-induced pulmonary fibrosis, probably due to its properties of anti-inflammation, SP-D inhibition and restoring increased CD4+CD25+ Tregs which may modulate Th1/Th2 imbalance by suppressing Th2 response (from Th2 polarity toward a Th1 dominant response).

Severe amiodarone induced pulmonary toxicity

A known complication of Amiodarone therapy is Amiodarone induced Pulmonary Toxicity (APT). Several features of this adverse effect make it difficult to diagnosis and treat. The case of a 63-year-old male with classic radiographic and histologic findings of APT is discussed. Clinical presentation, pathophysiology, diagnostic findings, and treatment strategies are reviewed. The patient was successfully managed with pulse high dose steroid therapy.

Herb-Drug Interaction of Paullinia cupana (Guarana) Seed Extract on the Pharmacokinetics of Amiodarone in Rats

Paullinia cupana is used in weight-loss programs as a constituent of medicinal/dietary supplements. This study aimed to assess a potential herb-drug interaction among a standardized (certified) Paullinia cupana extract and amiodarone (narrow therapeutic index drug) in rats. In a first pharmacokinetic study rats were simultaneously coadministered with a single dose of Paullinia cupana (821 mg/kg, p.o.) and amiodarone (50 mg/kg, p.o.), and in a second study rats were pretreated during 14 days with Paullinia cupana (821 mg/kg/day, p.o.) receiving amiodarone (50 mg/kg, p.o.) on the 15th day. Rats of the control groups received the corresponding volume of vehicle. Blood samples were collected at several time points after amiodarone dosing, and several tissues were harvested at the end of the experiments (24 h after dose). Plasma and tissue concentrations of amiodarone and its major metabolite (mono-N-desethylamiodarone) were measured and analysed. A significant reduction in the peak plasma concentration (73.2%) and in the extent of systemic exposure (57.8%) to amiodarone was found in rats simultaneously treated with Paullinia cupana and amiodarone; a decrease in tissue concentrations was also observed. This paper reports for the first time an herb-drug interaction between Paullinia cupana extract and amiodarone, which determined a great decrease on amiodarone bioavailability in rats.

In vitro exposure of precision-cut lung slices to 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole lysylamide dihydrochloride (NSC 710305, Phortress) increases inflammatory cytokine content and tissue damage

The anticancer drug (2-[4-amino-3-methylphenyl]-5-fluorobenzothiazole lysylamide dihydrochloride) (NSC 710305, Phortress) is a metabolically activated prodrug that causes DNA adduct formation and subsequent toxicity. Preclinically, it was found that hepatic, bone marrow, and pulmonary toxicity presented challenges to developing this drug. An ex vivo precision-cut lung slice (PCLS) model was used to search for concentration dependent effects of NSC 710305 (10, 25, 50, and 100 µM) on cytokine content, protein content, and immuno/histological endpoints. Preparation and culture of PCLS caused an initial spike in proinflammatory cytokine expression and therefore treatment with NSC 710305 was delayed until 48 h after initiating the slice cultures to avoid confounding the response to slicing with any drug response. PCLSs were evaluated after 24, 48, and 72 h exposures to NSC 710305. Reversibility of toxicity due to the 72-h treatment was evaluated after a 24-h recovery period. NSC 710305 caused a concentration-dependent cytokine response, and only the toxicity caused by a 72-h exposure to 25 µM reversed during the 24-h recovery period. Immuno/histological examination and quantitation of tissue protein levels indicated that tissue destruction, ED-1 (activated macrophage) staining, and protein levels were associated with the levels of proinflammatory cytokines in the tissue. In conclusion, the concentration- and time-dependent inflammatory response of PCLS to NSC 710305 preceded relevant tissue damage by a few days. The no-observable adverse effect level (NOAEL) for 24, 48, and 72 h exposures was established as 10 µM NSC 710305.

Dronedarone-associated acute renal failure: evidence coming from the Italian spontaneous ADR reporting database

AIM

To describe cases of acute renal failure (ARF) and of renal failure (RF) from dronedarone retrieved in the general population during post-marketing surveillance through the Italian spontaneous ADR reporting database.

METHODS

A case by case analysis was performed. Reports codified with the System Organ Class (SOC) term 'urinary system disorders' of the ADR terminology of the World Health Organization associated with dronedarone treatment were selected.

RESULTS

Out of 124,069 ADR reports, in 55 of them dronedarone was listed as the suspected drug. Among these reports, we identified four cases of ARF, two of RF and three cases of increase of blood creatinine submitted by physicians between October 2010 and December 2011. The patient age was from 61 to 84 years and most cases occurred within the first 13 days of initiation of dronedarone therapy (range 6 days-2 months). Only one patient received a co-suspected drug labelled for causing ARF. In all reports but one, positive dechallenge was reported.

CONCLUSIONS

Clinicians should be made aware of the risk of ARF/RF associated with dronedarone and of the need to screen patients appropriately for ARF/RF risk factors before starting dronedarone therapy.

Drug-induced interstitial lung disease: mechanisms and best diagnostic approaches

Drug-induced interstitial lung disease (DILD) is not uncommon and has many clinical patterns, ranging from benign infiltrates to life-threatening acute respiratory distress syndrome. There are two mechanisms involved in DILD, which are probably interdependent: one is direct, dose-dependent toxicity and the other is immune-mediated. Cytotoxic lung injury may result from direct injury to pneumocytes or the alveolar capillary endothelium. Drugs can induce all types of immunological reactions described by Gell and Coombs; however, most reactions in immune-mediated DILD may be T cell-mediated.

DILD can be difficult to diagnose; diagnosis is often possible by exclusion alone. Identifying the causative drug that induces an allergy or cytotoxicity is essential for preventing secondary reactions.

One method to confirm the diagnosis of a drug-induced disease is re-exposure or re-test of the drug. However, clinicians are reluctant to place patients at further risk of illness, particularly in cases with severe drug-induced diseases. Assessment of cell-mediated immunity has recently increased, because verifying the presence or absence of drug-sensitized lymphocytes can aid in confirmation of drug-induced disease. Using peripheral blood samples from drug-allergic patients, the drug-induced lymphocyte stimulation test (DLST) and the leukocyte migration test (LMT) can detect the presence of drug-sensitized T cells. However, these tests do not have a definite role in the diagnosis of DILD. This study explores the potential of these new tests and other similar tests in the diagnosis of DILD and provides a review of the relevant literature on this topic.

Lymphoid hyperplasia and eosinophilic pneumonia as histologic manifestations of amiodarone-induced lung toxicity

Amiodarone use is often limited by pulmonary toxicity. Amiodarone lung disease (ALD) classically manifests as organizing pneumonia with intra-alveolar foamy macrophages, but other patterns may also occur. Here we report 2 previously unreported patterns of ALD: lymphoid hyperplasia (LH) and eosinophilic pneumonia (EP). We identified patients with LH or EP as a prominent feature among 75 cases of probable ALD from the authors' teaching files collected from 1997 to 2010. Clinical history and lung wedge biopsies were reviewed. Twelve patients (7 men) met inclusion criteria (median age, 71 y). The exact amiodarone dose was known in all cases (median, 200 mg/d). Treatment duration was known in 10 cases and ranged from 1 to 12 years. Thoracic imaging showed diffuse infiltrates causing concern for a diagnosis of ALD. Histologic review revealed intra-alveolar foamy macrophages in all cases. Eight cases prominently displayed patterns of LH, including diffuse LH (7), follicular bronchiolitis (5), lymphoid interstitial pneumonia (2), and lymphocytic perivascular cuffing (2). Two showed features of acute EP, including diffuse alveolar damage with abundant eosinophils. Two showed features of chronic EP, including interstitial pneumonia with abundant eosinophils, patchy organization, and fibrinous exudates with macrophages and eosinophils. One chronic EP case also showed focal LH. Additional features included intra-alveolar giant cells (6), pleuritis (3), small poorly formed granulomas (3), and thrombi (2). LH and EP are previously unrecognized histopathologic manifestations of ALD, and amiodarone exposure should be included in their differential diagnosis.

Acute fibrinous and organizing pneumonia and undifferentiated connective tissue disease: a case report

Acute fibrinous and organizing pneumonia (AFOP), recently described, is a histologic pattern characterized by the presence of fibrin “balls” within alveolar spaces. The term undifferentiated connective tissue disease (UCTD) is used to identify autoimmune systemic diseases that do not fulfill the criteria to be classified as a definitive connective tissue disease. The AFOP has never been reported in association with UCTD. The present reported case is a 39-year-old Caucasian, female with dry cough and progressive dyspnea. Eight months later, she was diagnosed with “organizing pneumonia” based on clinical history and radiologic images. She manifested Raynaud's Phenomenon, sicca syndrome, boot and gloves neuropathic pain, and previous hypothyroidism. Antinuclear antibody, rheumatoid factor, and specific autoantibodies were negative. Salivary gland biopsy and electroneuromyiography were normal. The capillaroscopy showed a “scleroderma” pattern with capillary deletion and ectasia. She experienced clinical and radiologic worsening. Despite being submitted to cyclophosphamide pulse, she developed hemorrhage and then died. Thoracotomy pulmonary specimen showed histological pattern of AFOP. This paper shows a rare association of AFOP with UCTD.

Prehospital amiodarone may increase the incidence of acute respiratory distress syndrome among patients at risk

PURPOSE

Amiodarone has been implicated as a risk factor for acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) when used in the hospital. This study aims to estimate whether prehospital amiodarone also increases the risk of ALI/ARDS.

MATERIALS

Adult patients admitted to 22 centers with at least 1 risk factor for developing ALI were recruited. In a secondary analysis of this cohort, the prehospital use of amiodarone was documented on admission, and the patients followed for the primary outcome of ALI and secondary outcomes of ARDS, the need for invasive ventilation, and mortality. Dose/duration of amiodarone therapy was not available. Propensity matching was performed to account for imbalances in being assigned to amiodarone. The adjusted risk for ALI/ARDS was then estimated from a conditional logistic regression model of this propensity-matched set.

RESULTS

Forty of 5584 patients were on amiodarone at the time of hospitalization; of those, 6 developed ALI, with 5 progressing to ARDS. In comparison, 371 patients not on amiodarone developed ALI, with 224 having ARDS. After propensity score matching, the prehospital use of amiodarone was not statistically associated with an increased risk for all ALI (odds ratio [OR], 1.8; 95% confidence interval [CI], 0.7-5.0; P = .25), invasive ventilation (OR, 1.9; 95% CI, 1.0-3.6; P = .059), or in-hospital mortality (OR, 1.2; 95% CI, 0.5-2.9; P = .75); but its use appeared to significantly increase the risk for ARDS (OR 3.8; 95% CI, 1.1-13.1; P = .036).

CONCLUSIONS

Prehospital use of amiodarone may independently increase the risk for ARDS in patients who have at least 1 predisposing condition for ALI.

Management of amiodarone-related thyroid problems

Amiodarone is a highly effective and well-established antiarrrhythmic drug. It can be used to treat supraventricular and ventricular tachyarrhythmias and has the added advantage of being well tolerated in patients with impaired left ventricular systolic function with a low incidence of arrhythmic events, such as torsades de pointes. However, owing to its marked lipid affinity, it is highly concentrated in tissues and is linked to a number of adverse effects, including thyroid dysfunction. Amiodarone can lead to both hypothyroidism (amiodarone-induced hypothyroidism) and less commonly hyperthyroidism (amiodarone-induced thyrotoxicosis) and relates to high iodine content within the molecule as well as to several unique intrinsic properties of amiodarone. Dronedarone is a recently approved antiarrhythmic drug. It is structurally very similar to amiodarone, however the iodine moiety, present with amiodarone has been removed and replaced with a methylsulfonamide group to reduce fat solubility and adverse effects. We present an overview of the effects of amiodarone on thyroid function and the treatment options available, as well as a brief insight into dronedarone and its potential as an alternative to amiodarone.