Amiodarone and dronedarone: An update

Atrial Arrhythmias in Patients With Pulmonary Hypertension

TOPIC IMPORTANCE

Atrial arrhythmias (AA) are common in patients with pulmonary hypertension (PH) and contribute to morbidity and mortality. Given the growing PH population, understanding the pathophysiology, clinical impact, and management of AA in PH is important.

REVIEW FINDINGS

AA occurs in PH with a 5-year incidence of 10% to 25%. AA confers a higher morbidity and mortality, and restoration of normal sinus rhythm improves survival and functionality. AA is thought to develop because of structural alterations of the right atrium caused by changes to the right ventricle (RV) due to elevated pulmonary artery pressures. AA can subsequently worsen RV function. Current guidelines do not provide comprehensive recommendations for the management of AA in PH. Robust evidence to favor a specific treatment approach is lacking. Although the role of medical rate or rhythm control, and the use of cardioversion and ablation, can be inferred from other populations, evidence is lacking in the PH population. Much remains to be determined regarding the optimal management strategy. We present here our institutional approach and discuss areas for future research.

SUMMARY

This review highlights the epidemiology and pathophysiology of AA in patients with PH, describes the relationship between AA and RV dysfunction, and discusses current management practices. We outline our institutional approach and offer directions for future investigation.

Dronedarone Attenuates Ang II-Induced Myocardial Hypertrophy Through Regulating SIRT1/FOXO3/PKIA Axis

BACKGROUND AND OBJECTIVES

Long-term pathological myocardial hypertrophy (MH) seriously affects the normal function of the heart. Dronedarone was reported to attenuate left ventricular hypertrophy of mice. However, the molecular regulatory mechanism of dronedarone in MH is unclear.

METHODS

Angiotensin II (Ang II) was used to induce cell hypertrophy of H9C2 cells. Transverse aortic constriction (TAC) surgery was performed to establish a rat model of MH. Cell size was evaluated using crystal violet staining and rhodamine phalloidin staining. Reverse transcription quantitative polymerase chain reaction and western blot were performed to detect the mRNA and protein expressions of genes. JASPAR and luciferase activity were conducted to predict and validate interaction between forkhead box O3 (FOXO3) and protein kinase inhibitor alpha (PKIA) promoter.

RESULTS

Ang II treatment induced cell hypertrophy and inhibited sirtuin 1 (SIRT1) expression, which were reversed by dronedarone. SIRT1 overexpression or PKIA overexpression enhanced dronedarone-mediated suppression of cell hypertrophy in Ang II-induced H9C2 cells. Mechanistically, SIRT1 elevated FOXO3 expression through SIRT1-mediated deacetylation of FOXO3 and FOXO3 upregulated PKIA expression through interacting with PKIA promoter. Moreover, SIRT1 silencing compromised dronedarone-mediated suppression of cell hypertrophy, while PKIA upregulation abolished the influences of SIRT1 silencing. More importantly, dronedarone improved TAC surgery-induced MH and impairment of cardiac function of rats via affecting SIRT1/FOXO3/PKIA axis.

CONCLUSIONS

Dronedarone alleviated MH through mediating SIRT1/FOXO3/PKIA axis, which provide more evidences for dronedarone against MH.

Synthesis of Novel Ferrocene-Benzofuran Hybrids via Palladium- and Copper-Catalyzed Reactions

The combination of the ferrocene skeleton with pharmacophores often leads to molecules with interesting biological properties. Five ferrocene-benzofuran hybrids of different structures were synthesized by transition metal catalyzed reactions. The efficiency of both homogeneous and heterogeneous catalytic methods was tested. The products were characterized using 1H, 13C NMR and FTIR spectroscopy, HRMS and cyclic voltammetry. The structure of one of the new compounds was also proved with X-ray crystallography. The new hybrids showed moderate cytotoxicity on MCF-7 and MDA-MB-231 cell lines. It is remarkable that the less curable MDA-MB-231 cell line was more sensitive to treatment with three ferrocene derivatives.

Ethnic-Related Sodium Voltage-Gated Channel α Subunit 5 Polymorphisms Shape the In Vitro Pharmacological Action of Amiodarone upon Nav1.5

Na_v1.5-derived Na⁺ current (I_Na) exerts a pivotal role in the depolarization phase of cardiomyocytes' action potential, and, therefore, changes in I_Na can contribute to fatal arrhythmias. Na_v1.5 displays naturally occurring ethnicity-related polymorphisms, which might alter the functioning and pharmacology of the channel. Some studies have shown how single-nucleotide polymorphism can change the response to antiarrhythmic drugs. Investigations on the role of Na_v1.5 in arrhythmogenesis associated with its functional polymorphisms are currently growing as well as the possible variability in the antiarrhythmic pharmacotherapy among ethnic groups. The influence of the ethnicity-related polymorphisms (S524Y, S1103Y, R1193Q, V1951L) on the responsiveness, selectivity, and pharmacological efficacy of the clinically used antiarrhythmic amiodarone (AMIO) is not completely known. Our objectives were to analyze biophysical and pharmacological aspects of four ethnicity-related polymorphisms before and after exposure to AMIO. Polymorphisms caused reduced AMIO potency compared with wild type (WT), which can vary by up to 4× between them. AMIO shifted the voltage dependency for current inactivation without significant effect in voltage-dependent activation to a similar extent in WT and polymorphisms. The recovery from inactivation was altered between the polymorphisms when compared with WT. Finally, the use dependency of AMIO differed between studied groups, especially at a more depolarized cell membrane. Thus, our work may guide future studies focusing on the efficiency of AMIO in treating different arrhythmias and establish more individualized guidelines for its use depending on the Na_v1.5 polymorphism after validating our findings using in vivo studies. SIGNIFICANCE STATEMENT: Sodium voltage-gated channel α subunit 5 (SCN5A) gene encodes the α subunit of Na_v1.5, the main cardiac voltage-gated Na⁺ channel. Interestingly, ethnicity-related polymorphisms are found in SCN5A. Amiodarone is used in clinical practice, and some of its effects are attributed to interaction with Na_v1.5. Important, amiodarone efficacy is variable among patients. Here we show that ethnicity-related SCN5A polymorphisms lead to altered Na_v1.5-amiodarone interaction, which may be the cause for the variable efficacy observed in clinical usage of amiodarone.

Pharmacokinetic interaction between dronedarone and ticagrelor following oral administration in rats

Dronedarone and ticagrelor have high co-administration potential in patients with both acute coronary syndrome and atrial fibrillation. The objective of the present in vivo study was to investigate the potential interaction between dronedarone (5 and 10 mg/kg) and ticagrelor (5 and 10 mg/kg) when administered orally to rats. Forty Sprague-Dawley rats were randomly distributed into eight groups; consisting of a dronedarone only group, a ticagrelor only group, a dronedarone with ticagrelor-pretreatment group, and a ticagrelor with dronedarone-pretreatment group. Pharmacokinetic exposure (AUC_inf = 1472 ng·h/mL) associated with administration of 10 mg/kg of dronedarone increased significantly, with delayed T _max in the group that received ticagrelor-pretreatment when compared to the dronedarone only group (AUC_inf = 723 ng·h/mL). In addition, pharmacokinetic exposure (AUC_inf = 2391 ng·h/mL) associated with administration of 10 mg/kg of ticagrelor increased significantly, with increased K _el (0.31 h^-1) and decreased V _z/F (14.6 L/kg) in the dronedarone-pretreatment group when compared to the ticagrelor only group (AUC_inf = 1616 ng·h/mL; K _el = 0.21 h^-1; V _z/F  =  31.3 L/kg). Results of our study suggest that further investigation of a potential interaction between dronedarone and ticagrelor in humans is justified and that caution may need to be exercised when dronedarone and ticagrelor pharmacotherapies concomitantly.

Synthesis of 2-Organylchalcogenopheno[2,3-b]pyridines from Elemental Chalcogen and NaBH4 /PEG-400 as a Reducing System: Antioxidant and Antinociceptive Properties

An alternative method to prepare 2-organylchalcogenopheno[2,3-b]pyridines was developed by the insertion of chalcogen species (selenium, sulfur or tellurium), generated in situ, into 2-chloro-3-(organylethynyl)pyridines by using the NaBH₄ /PEG-400 reducing system, followed by an intramolecular cyclization. It was possible to obtain a series of compounds with up to 93 % yield in short reaction times. Among the synthesized products, 2-organyltelluropheno[2,3-b]pyridines have not been described in the literature so far. Moreover, the compounds 2-phenylthieno[2,3-b]pyridine (3 b) and 2-phenyltelluropheno[2,3-b]pyridine (3 c) exhibited significant antioxidant potential in different in vitro assays. Further studies demonstrated that compound 3 b exerted an antinociceptive effect in acute inflammatory and non-inflammatory pain models, thus indicating the involvement of the central and peripheral nervous systems on its pharmacological action. More specifically, our results suggest that the intrinsic antioxidant property of compound 3 b might contribute to attenuating the nociception and inflammatory process on local injury induced by complete Freund's adjuvant (CFA).

Dronedarone-Mediated Acute Hepatic and Renal Toxicity

Dronedarone, a drug similar in chemical properties to amiodarone, was designed to have similar pharmacodynamic properties as amiodarone with fewer side effects. Although there have been cases of chronic liver enzyme elevation with dronedarone, only a few cases have been reported in literature where it has led to rapid onset of liver failure. We present the case of an 86-year-old male who developed acute liver failure concomitantly with acute kidney failure after he was started on dronedarone therapy.

Assessment of OMT-28, a synthetic analog of omega-3 epoxyeicosanoids, in patients with persistent atrial fibrillation: Rationale and design of the PROMISE-AF phase II study

We designed a placebo controlled, double-blind, randomized, dose-finding phase II study on OMT-28 in the maintenance of sinus rhythm after electrical cardioversion (DCC) in patients with persistent atrial fibrillation (PROMISE-AF). OMT-28 is a first-in-class, synthetic analog of 17,18-epoxyeicosatetetraenoic acid, a bioactive lipid mediator generated by cytochrome P450 enzymes from the omega-3 fatty acid eicosapentaenoic acid. OMT-28 improves Ca²⁺-handling and mitochondrial function in cardiomyocytes and reduces pro-inflammatory signaling. This unique mode of action may provide a novel approach to target key mechanism contributing to AF pathophysiology. In a recent phase I study, OMT-28 was safe and well tolerated and showed favorable pharmacokinetics. The PROMISE-AF study (NCT03906799) is designed to assess the efficacy (primary objective), safety, and population pharmacokinetics (secondary objectives) of three different doses of OMT-28, administered once daily, versus placebo until the end of the follow-up period. Recruitment started in March 2019 and the study will include a total of 120 patients. The primary efficacy endpoint is the AF burden (% time with any AF), evaluated over a 13-week treatment period after DCC. AF burden is calculated based on continuous ECG monitoring using an insertable cardiac monitor (ICM). The primary efficacy analysis will be conducted on the modified intention-to-treat (mITT) population, whereas the safety analysis will be done on the safety population. Although ICMs have been used in other interventional studies to assess arrhythmia, PROMISE-AF will be the first study to assess antiarrhythmic efficacy and safety of a novel rhythm-stabilizing drug after DCC by using ICMs.

Amiodarone that has antibacterial effect against human pathogens may represent a novel catheter lock

Infection is one of the most feared hospital-acquired complications. Infusion therapy is frequently administered through a central line. Infusions facilitating bacterial growth may be a source of central line-associated bloodstream infections. On the other hand, medications that kill bacteria may protect against this kind of infection and may be used as a catheter lock.In this study, we examined the impact of amiodarone on bacterial growth. Amiodarone is used for controlling cardiac arrhythmias and can be administered as an infusion for weeks. Standard microbiological methods have been used to study the growth of laboratory strains and clinical isolates of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and multidrug-resistant Acinetobacter baumannii in amiodarone. The minimum inhibitory concentration (MIC) of amiodarone was determined. Bacterial growth from in use amiodarone syringes and giving sets was also investigated.Most examined strains were killed within 1 min in amiodarone. The other strains were killed within 1 h. The MICs of amiodarone were <0.5-32 μg/mL.Amiodarone infusion is unlikely to be responsible for bloodstream infections as contaminating bacteria are killed within 1 h. Amiodarone may also protect against central line infections if used as a catheter lock.

[Amiodarone-induced optic neuropathy: A rare side effect]

INTRODUCTION

The diagnosis of bilateral papilledema implies emergency medical care to look for intracranial hypertension and arteritic ischemic neuropathy. However, other causes must also be mentioned, including drugs. Too often underrated because of their usual benignity, drug side ophthalmological effects can be severe and are typically bilateral.

CASE REPORT

An 80-year-old woman was hospitalized for bilateral papilledema, predominantly in the left eye, with lowered visual acuity. After ruling out intracranial hypertension, arteritic ischemic optic neuropathy, non-arteritic, and inflammatory bilateral papilledema, the diagnosis was toxic optic neuropathy.

CONCLUSION

Bilateral edematous optic neuropathy is a known side effect of amiodarone, uncommon but to be known because of the large number of patients benefiting from this treatment.

Influence of concomitant medication on plasma concentration of amiodarone in patients with atrial fibrillation - a pilot study

Background

Although amiodarone is a drug with many side effects, it is one of the most commonly used drugs in the treatment and prophylaxis of supraventricular and ventricular arrhythmias.

Aim

The purpose of this pilot study was to evaluate plasma concentrations of amiodarone in patients with atrial fibrillation (AF) and to identify possible drug-drug interactions between amiodarone and concomitant medications.

Method

A prospective observational study was conducted in 27 consecutive patients treated with amiodarone from May to July 2017 in a Clinical University Hospital. The patients included met our inclusion criteria. HPLC-UV was the device used to determine the plasma concentration of amiodarone.

Results

Only 51.8% of the patients had amiodarone plasma concentration within therapeutic interval (500–2500 ng/ml). The drugs associated to amiodarone in the therapeutic plan were diuretics, beta blockers, statins, antiplatelets, fluoroquinolones, non-steroidal anti-inflammatory drugs. We observed a statistically significant difference between the plasmatic concentrations of amiodarone in patients treated with furosemide vs. patients concomitantly treated with other drugs. Interactions between other mentioned drugs and amiodarone were not registered. We can report an underuse of amiodarone for more than 50% of the patients. Also, we found a significant interaction between furosemide and amiodarone, most likely through the interaction with MDR.

Conclusion

Furosemide may influence the pharmacokinetics of P-gp-interfering drugs. However, the relevance of these findings needs to be confirmed and further research is needed to characterize the interaction between amiodarone and furosemide.

Atria-selective antiarrhythmic drugs in need of alliance partners

Atria-selective antiarrhythmic drugs in need of alliance partners. Guideline-based treatment of atrial fibrillation (AF) comprises prevention of thromboembolism and stroke, as well as antiarrhythmic therapy by drugs, electrical rhythm conversion, ablation and surgical procedures. Conventional antiarrhythmic drugs are burdened with unwanted side effects including a propensity of triggering life-threatening ventricular fibrillation. In order to solve this therapeutic dilemma, 'atria-selective' antiarrhythmic drugs have been developed for the treatment of supraventricular arrhythmias. These drugs are designed to aim at atrial targets, taking advantage of differences in atrial and ventricular ion channel expression and function. However it is not clear, whether such drugs are sufficiently antiarrhythmic or whether they are in need of an alliance partner for clinical efficacy. Atria-selective Na⁺ channel blockers display fast dissociation kinetics and high binding affinity to inactivated channels. Compounds targeting atria-selective K⁺ channels include blockers of ultra rapid delayed rectifier (Kv1.5) or acetylcholine-activated inward rectifier K⁺ channels (Kir3.x), inward rectifying K⁺ channels (Kir2.x), Ca²⁺-activated K⁺ channels of small conductance (SK), weakly rectifying two-pore domain K⁺ channels (K_2P), and transient receptor potential channels (TRP). Despite good antiarrhythmic data from in-vitro and animal model experiments, clinical efficacy of atria-selective antiarrhythmic drugs remains to be demonstrated. In the present review we will briefly summarize the novel compounds and their proposed antiarrhythmic action. In addition, we will discuss the evidence for putative improvement of antiarrhythmic efficacy and potency by addressing multiple pathophysiologically relevant targets as possible alliance partners.

Amiodarone-Related Pure Red Cell Aplastic Anemia and Hypothyroidism in a Child With Total Anomalous Pulmonary Venous Connection

Introduction: Amiodarone is an effective anti-arrhythmic drug, but there are many clinical side effects that limit its application. There are no case reports of amiodarone-related pure red cell aplastic anemia (PRCA). Case Presentation: Here, we present a case of amiodarone-related PRCA and hypothyroidism in a 7-month-old boy. The patient had a total anomalous pulmonary venous connection (the cardiac type) and had undergone cardiac surgery at the age of 2 months. Eleven days after the operation, atrial tachycardia was observed. Amiodarone was administered orally (15 mg/kg.d), following which the arrhythmia was under control. Subsequently, the patient was prescribed amiodarone (5 mg/kg.d) and discharged. Regular medical consultations were not conducted as required. At 7 months of age (5 months after the operation), the patient returned to the hospital for re-examination. The electrocardiogram showed intermittent sinus bradycardia, occasional junctional escape beats, hemoglobin 7.9 g/DL, and thyroid function-TSH 9.660 uIU/mL. Results: Amiodarone was discontinued. Thyroxine was administered orally. Subsequently, the heart rate improved and TSH returned to normal levels. Nutritional therapy was recommended based on a diagnosis of nutrition-related anemia. A re-visit at 9 months of age showed that the weight was 6 kg, but the routine blood test indicated that hemoglobin was 5.9 g/DL with positive cell anemia and low reticulocyte count. Bone marrow cytology examination suggested PRCA. The hemoglobin level was gradually restored after treatment with prednisone. Conclusion: The use of amiodarone in small infants and young children and its side effects should be carefully monitored. The potential mechanism of amiodarone-related PRCA needs further study.

Synthesis of 2,3-bis-organochalcogenyl-benzo[b]chalcogenophenes promoted by Oxone®

We report here an alternative and tunable metal-free synthesis of benzo[b]chalcogenophenes via the electrophilic cyclization of 2-functionalized chalcogenoalkynes promoted by Oxone®.

Amiodarone-Associated Optic Neuropathy: Clinical Review

Amiodarone, an antiarrhythmic agent, has been associated with visual loss secondary to optic neuropathy. The reported mean duration of amiodarone use before visual loss is about 9 months. Patients receiving amiodarone have a 2-fold increased risk of developing optic neuropathy, especially in males and possibly in patients with longer duration of treatment. Amiodarone-associated optic neuropathy is characterised by an insidious onset, slow progression, bilateral simultaneous visual loss, and protracted disc swelling. After discontinuing amiodarone use, visual acuity and visual field deficits tend to improve or stabilise in most patients, with about 20% of the patients getting worse.