Adverse effects of low dose amiodarone: a meta-analysis

The impact of cardiovascular drugs on hyperglycemia and diabetes: a review of 'unspoken' side effects

AIMS

The increasing prevalence of cardiovascular diseases has led to the widespread use of cardiovascular drugs that can adversely impact glucose metabolism. This review focuses on the latest evidence on the potential of cardiovascular drugs to induce adverse glycemic effects but also the underlying mechanisms, prevention, and management strategies.

MATERIALS AND METHODS

A comprehensive literature search was conducted across scientific databases until May 25th, 2024.

RESULTS

Certain cardiovascular drugs can induce hyperglycemia through multiple mechanisms, including altered the secretion and sensitivity of insulin through direct cytotoxic effects toward pancreatic beta cells and increased glucose secretion. Notably, diuretics, beta-blockers, calcium channel blockers, and statins have been associated with significant glycemic disturbances. The risk of hyperglycemia varies based on individual factors, drug dosages, and concurrent medications. These drug-induced hyperglycemic effects may sometimes reverse upon discontinuation of related medication. Effective management should include lifestyle modifications, the use of glucose-lowering medications, and opting for lower-risk cardiovascular drugs. Monitoring for hyperglycemia involves educating affected individuals and conducting regular blood glucose tests. Identifying at-risk individuals and implementing preventive measures are crucial for improving both cardiovascular and metabolic outcomes.

CONCLUSIONS

Certain cardiovascular drugs significantly contribute to hyperglycemia and diabetes mellitus through various mechanisms. Effective management includes identifying at-risk individuals, choosing lower-risk medications, and implementing monitoring and preventive strategies. Further research is needed to fully understand these mechanisms and develop targeted interventions to prevent and manage cardiovascular drug-induced hyperglycemia, thereby improving clinical outcomes.

The Safety Profile of Amiodarone Among Older Adults (Age ≥75 Years): A Pharmacovigilance Study from the FDA Data

BACKGROUND

Amiodarone is a widely used antiarrhythmic agent with significant toxicities and drug interactions more likely to affect older adults. Nevertheless, data regarding amiodarone safety in this population are limited.

METHODS

We conducted a retrospective analysis of FDA [Food and Drug Administration] Adverse Event Reporting System (FAERS) data from 2003 to 2024. Reports with amiodarone as the primary suspect were compared with other antiarrhythmics (sotalol, dronedarone, flecainide, propafenone, dofetilide). Disproportionality analysis assessed reporting odds ratios (RORs) for predefined adverse events in adults (<75 years) and older adults (≥75 years). Interaction analysis evaluated differences between age groups.

RESULTS

Among 9196 amiodarone FAERS reports, 4129 (44.9%) involved older adults. Hyperthyroidism (ROR 39.1; 95% confidence interval [CI], 25-61 and ROR 23.4; 95% CI, 11-49.8) and hypothyroidism (ROR 36.9; 95% CI, 15.2-89.8 and ROR 24.5; 95% CI, 11.5-52.1) were substantially over-reported in amiodarone users among both adults and older adults, respectively. Drug-induced liver injury and peripheral neuropathy were also over-reported without a significant age interaction. Interstitial lung disease was reported more frequently in amiodarone users overall, with significantly higher reporting in older adults (ROR 11.4; 95% CI, 6.9-18.6 vs 4.9; 95% CI, 3.4-7.0; Pinteraction = .007). Bradycardia was also over-reported in older adults compared with adults (ROR 1.6; 95% CI, 1.3-2 vs 1.0; 95% CI, 0.8-1.3; Pinteraction = .003). Torsades de pointes/QT prolongation were less frequently reported in both age groups.

CONCLUSIONS

In this global postmarketing study, interstitial lung disease and bradycardia were more frequently reported in older adults treated with amiodarone. These findings support vigilant monitoring for these adverse events, particularly in older patients.

Temporal trends in population characteristics and type of device among primary prevention implantable cardioverter defibrillator recipients: The DAI-PP programme

BACKGROUND

Patient characteristics, technology and clinical practice surrounding primary prevention implantable cardioverter defibrillators have evolved continuously over time.

AIM

To explore the temporal changes in patient characteristics, pharmacological therapy and device types among implantable cardioverter defibrillator recipients implanted for the primary prevention of sudden cardiac death over the last two decades in France.

METHODS

Characteristics of participants and type of device from the retrospective DAI-PP Pilot Study (2002-2012) were compared with those from the ongoing prospective DAI-PP Consortium (2018 onwards).

RESULTS

This study included 9588 participants overall (DAI-PP Pilot Study, n=5539; DAI-PP Consortium, n=4049). Compared with the DAI-PP Pilot Study, the DAI-PP Consortium subjects were older at implantation (62.5 vs 65.2 years; P=0.001) and had a higher proportion of women (15.1% vs 20.6%; P<0.001), a similar proportion of ischaemic heart disease (60.2% vs 60.2%; P=0.98), a higher left ventricular ejection fraction (27±7% vs 30±8%; P<0.001) and more patients with narrow QRS complexes (30.5% vs 46.0%; P<0.001). The proportion of patients treated with heart failure drugs increased significantly (70.1% vs 83.1%; P<0.001), whereas the use of amiodarone became much less frequent (22.7% vs 14.7%; P<0.001). Finally, the proportions of cardiac resynchronization therapy defibrillators (53.8% vs 46.4%; P<0.001) and dual-chamber defibrillators (23.3% vs 17.3%; P<0.001) decreased, whereas subcutaneous implantable cardioverter defibrillators now account for a sizeable proportion of implants (14.6%).

CONCLUSIONS

Over a 20-year period, the primary prevention implantable cardioverter defibrillator population has evolved significantly, with an older age and a higher proportion of women. The type of device has changed, with fewer cardiac resynchronization therapy defibrillators and more subcutaneous implantable cardioverter defibrillators.

Amiodarone-induced ocular and extra-ocular toxicity: a retrospective cohort study

Amiodarone (AMD) is a largely employed anti-arrhythmic agent for the treatment of recurrent supraventricular and ventricular tachyarrhythmias. Because of its lipophilic properties, prolonged half-life and prevailing biliary excretion, it is not rarely responsible for potentially severe adverse events that can involve one or more organs with a prevalence ranging from 15% in the first year of drug intake to 50% in patients treated for a longer time. In addition to pro-arrhythmia effects, AMD toxicity may result in a variable combination of clinical manifestations, including visual impairment, thyroid dysfunctions, pulmonary diseases, liver injury, neutropenia or thrombocytopenia. We aimed to describe the AMD-induced ophthalmologic and non-ophthalmologic side effects observed in a longitudinal cohort of patients. Seventeen Caucasian patients, who were on amiodarone therapy for a variable period, were enrolled in this retrospective, cross-sectional, observational study. All of them were referred to the Department of Ophthalmology and Neuroscience of the University of Bari, Italy, because of visual disturbances of variable severity. Three patients were given 3 intravenous boluses of 150 mg AMD followed by progressively decreasing oral doses, whereas 14 patients received a loading daily dose of 600-1200 mg orally, reduced after 2-3 weeks to a maintenance daily dose of 200-400 mg. All patients underwent complete clinical and laboratory assessments, according to a standard protocol. Ophthalmologic examination included intraocular pressure, ocular motility, visual field testing, angiography, optical coherence tomography, best-corrected visual acuity (BCVA) and grading of AMD-induced keratopathy by slit-lamp biomicroscopy. At diagnosis, eye disorders ranging from blurred vision and deterioration of visual acuity to eye redness and progressive glare were reported in 14 patients and lasting photophobia in the remaining 3 patients. Verticillate keratopathy (VK), stage 1-4, was diagnosed in all of them. Following AMD cessation, the patients were checked after a mean of 94 days and clear corneas were found in 12 of them, whereas lower-stage VK persisted in 5 patients. A 20/40 visual outcome or better was detected in 29 of 34 eyes (85.3%). Bilateral optic disk edema was found in 3 patients. Fundoscopic examination performed 23 months after AMD discontinuation showed that optic disk edema was reduced in all 3 patients, though to a variable extent. Optic neuropathy with protracted disk edema was diagnosed in a single patient who complained of progressive visual loss. Almost 2 months after AMD cessation, disk edema was reduced in OD > OS and BCVA partially improved. Extra-ocular manifestations included poorly symptomatic hypothyroidism in 2 patients, and overt myxedema, cholestatic liver injury, pancytopenia and interstitial pneumonitis associated with subclinical hypothyroidism in one patient each. A point stemming from our study and not clearly emphasized in the literature is that while a higher maintenance dose of AMD for a longer time was responsible for the most advanced grade 4 VK, no correlation was found between the occurrence of extra-ocular manifestations and the severity of ophthalmological signs or complaints. Patients assuming AMD should undergo close monitoring by specialist clinicians of a multidisciplinary team with the aim of an early recognition of eye, thyroid, liver and lung toxicities, thus preventing more serious complications.

Comparison of Mitochondrial and Antineoplastic Effects of Amiodarone and Desethylamiodarone in MDA-MB-231 Cancer Line

Previously, we have demonstrated that amiodarone (AM), a widely used antiarrhythmic drug, and its major metabolite desethylamiodarone (DEA) both affect several mitochondrial processes in isolated heart and liver mitochondria. Also, we have established DEA's antitumor properties in various cancer cell lines and in a rodent metastasis model. In the present study, we compared AM's and DEA's mitochondrial and antineoplastic effects in a human triple-negative breast cancer (TNBC) cell line. Both compounds reduced viability in monolayer and sphere cultures and the invasive growth of the MDA-MB-231 TNBC line by inducing apoptosis. They lowered mitochondrial trans-membrane potential, increased Ca2+ influx, induced mitochondrial permeability transition, and promoted mitochondrial fragmentation. In accordance with their mitochondrial effects, both substances massively decreased overall, and even to a greater extent, mitochondrial ATP production decreased, as determined using a Seahorse live cell respirometer. In all these effects, DEA was more effective than AM, indicating that DEA may have higher potential in the therapy of TNBC than its parent compound.

A Fatal Consequence: Amiodarone-Induced Multiorgan Toxicity

Amiodarone is commonly used nowadays for the treatment of atrial fibrillation (AF). The wide use of this medication has led to the occurrence of adverse events, including pulmonary toxicity, hepatotoxicity, thyroid dysfunction, and many others. Higher doses of Amiodarone of ≥400 mg/day have been linked to increased complications. We present a case of a 70-year-old male with multivessel coronary artery disease (CAD) with ischemic cardiomyopathy and severe peripheral artery disease (PAD) who underwent an elective left femoral to posterior tibial bypass surgery followed by percutaneous coronary intervention (PCI) complicated by new-onset AF. The patient was loaded with 150 mg of intravenous (IV) Amiodarone followed by 360 mg infusion over six hours for chemical cardioversion. The patient was then maintained on oral Amiodarone 400 mg/day until the day of presentation when he complained of progressive dyspnea. Imaging was significant for diffuse ground glass opacities and interstitial thickening. The echocardiogram revealed an improved ejection fraction (EF) of 40% from 20%. The patient had worsening oxygenation despite adequate IV diuresis and developed severe acute respiratory distress syndrome (ARDS) requiring mechanical ventilation (MV). A bronchoscopy with bronchoalveolar lavage (BAL) showed diffuse alveolar hemorrhage (DAH) with a high lymphocyte count and negative infectious disease testing. Lab tests revealed elevated liver enzyme levels. There were also changes in thyroid function from baseline with elevated free T4 at 1.83 ng/dL (0.8-1.4 ng/dL), suppressed thyroid stimulating hormone (TSH) at 0.109 mIU/mL (0.4-4 mIU/mL), negative anti-thyroglobulin (TG) antibodies, and anti-thyroid peroxidase (TPO) antibodies indicating a type 2 Amiodarone-induced thyrotoxicosis. Unfortunately, the patient's condition deteriorated further despite appropriate treatment, and it was ultimately followed by his demise. Severe, fatal cases of Amiodarone toxicity are scarce, but more reports are being seen. We strongly believe clinicians should have a high index of suspicion for Amiodarone-related adverse events in elderly males with cardiopulmonary comorbidities. It is imperative to have an increased understanding, greater vigilance, and closer monitoring of pulmonary function tests (PFTs), laboratory tests, and imaging studies.

Microfluidic production of amiodarone loaded nanoparticles and application in drug repositioning in ovarian cancer

Amiodarone repositioning in cancer treatment is promising, however toxicity limits seem to arise, constraining its exploitability. Notably, amiodarone has been investigated for the treatment of ovarian cancer, a tumour known for metastasizing within the peritoneal cavity. This is associated with an increase of fatty acid oxidation, which strongly depends on CPT1A, a transport protein which has been found overexpressed in ovarian cancer. Amiodarone is an inhibitor of CPT1A but its role still has to be explored. Therefore, in the present study, amiodarone was tested on ovarian cancer cell lines with a focus on lipid alteration, confirming its activity. Moreover, considering that drug delivery systems could lower drug side effects, microfluidics was employed for the development of drug delivery systems of amiodarone obtaining simultaneously liposomes with a high payload and amiodarone particles. Prior to amiodarone loading, microfluidics production was optimized in term of temperature and flow rate ratio. Moreover, stability over time of particles was evaluated. In vitro tests confirmed the efficacy of the drug delivery systems.

Amiodarone and pulmonary toxicity in atrial fibrillation: a nationwide Israeli study

BACKGROUND AND AIMS

Amiodarone-related interstitial lung disease (ILD) is the most severe adverse effect of amiodarone treatment. Most data on amiodarone-related ILD are derived from periods when amiodarone was given at higher doses than currently used.

METHODS

A nationwide population-based study was conducted among patients with incident atrial fibrillation (AF) between 1 December 1999 and 31 December 31 2021. Amiodarone-exposed patients were matched 1:1 with controls unexposed to amiodarone based on age, sex, ethnicity, and AF diagnosis duration. The final patient cohort included only matched pairs where amiodarone therapy was consistent throughout follow-up. Directed acyclic graphs and inverse probability treatment weighting (IPTW) modelling were used. Patients with either prior ILD or primary lung cancer (PLC) were excluded. The primary outcome was the incidence of any ILD. Secondary endpoints were death and PLC.

RESULTS

The final cohort included 6039 amiodarone-exposed patients who were matched with unexposed controls. The median age was 73.3 years, and 51.6% were women. After a mean follow-up of 4.2 years, ILD occurred in 242 (2.0%) patients. After IPTW, amiodarone exposure was not significantly associated with ILD [hazard ratio (HR): 1.45, 95% confidence interval (CI): 0.97, 2.44, P = 0.09]. There was a trivial higher relative risk of ILD among amiodarone-exposed patients between Years 2 and 8 of follow-up [maximal risk ratio (RR): 1.019]. Primary lung cancer occurred in 97 (0.8%) patients. After IPTW, amiodarone was not associated with PLC (HR: 1.18, 95% CI: 0.76, 2.08, P = 0.53). All-cause death occurred in 2185 (18.1%) patients. After IPTW, amiodarone was associated with reduced mortality risk (HR: 0.65, 95% CI: 0.60, 0.72, P < 0.001). The results were consistent across a variety of sensitivity analyses.

CONCLUSION

In a contemporary AF population, low-dose amiodarone was associated with a trend towards increased risk of ILD (15%-45%) but a clinically negligible change in absolute risk (maximum of 1.8%), no increased risk of PLC, and a lower risk of all-cause mortality.

Junctional Ectopic Tachycardia Caused by Junctophilin-2 Expression Silencing Is Selectively Sensitive to Ryanodine Receptor Blockade

Junctional ectopic tachycardia (JET) is a potentially fatal cardiac arrhythmia. Hcn4:shJph2 mice serve as a model of nodal arrhythmias driven by ryanodine type 2 receptor (RyR2)-mediated Ca2+ leak. EL20 is a small molecule that blocks RyR2 Ca2+ leak. In a novel in vivo model of JET, Hcn4:shJph2 mice demonstrated rapid conversion of JET to sinus rhythm with infusion of EL20. Primary atrioventricular nodal cells demonstrated increased Ca2+ transient oscillation frequency and increased RyR2-mediated stored Ca2+ leak which was normalized by EL20. EL20 was found to be rapidly degraded in mouse and human plasma, making it a potential novel therapy for JET.

Prevention of postoperative atrial fibrillation in cardiac surgery: a quality improvement project

PURPOSE

Postoperative atrial fibrillation (POAF) has an incidence of 20-60% in cardiac surgery. The Society of Cardiovascular Anesthesiologists and the European Association of Cardiothoracic Anaesthesiology Practice Advisory have recommended postoperative beta blockers and amiodarone for the prevention of POAF. By employing quality improvement (QI) strategies, we sought to increase the use of these agents and to reduce the incidence of POAF among our patients undergoing cardiac surgery.

METHODS

This single-centre QI initiative followed the traditional Plan, Do, Study, Act (PDSA) cycle scientific methodology. A POAF risk score was developed to categorize all patients undergoing cardiac surgery as either normal or elevated risk. Risk stratification was incorporated into a preprinted prescribing guide, which recommended postoperative beta blockade for all patients and a postoperative amiodarone protocol for patients with elevated risk starting on postoperative day one (POD1). A longitudinal audit of all patients undergoing cardiac surgery was conducted over 11 months to track the use of prophylactic medications and the incidence of POAF.

RESULTS

Five hundred and sixty patients undergoing surgery were included in the QI initiative from 1 December 2020 to 1 November 2021. The baseline rate of POAF across all surgical subtypes was 39% (198/560). The use of prophylactic amiodarone in high-risk patients increased from 13% (1/8) at the start of the project to 41% (48/116) at the end of the audit period. The percentage of patients receiving a beta blocker on POD1 did fluctuate, but remained essentially unchanged throughout the audit (34.8% in December 2020 vs 46.7% in October 2021). After 11 months, the overall incidence of POAF was 29% (24.9% relative reduction). Notable reductions in the incidence of POAF were observed in more complex surgical subtypes by the end of the audit, including multiple valve replacement (89% vs 56%), aortic repair (50% vs 33%), and mitral valve surgery (45% vs 33%).

CONCLUSIONS

This single-centre QI intervention increased the use of prophylactic amiodarone by 28% for patients at elevated risk of POAF, with no change in the early postoperative initiation of beta blockers (46.7% of patients by POD1). There was a notable reduction in the incidence of POAF in patients at elevated risk undergoing surgery.

CLOSE-Guided Pulmonary Vein Isolation to Treat Persistent Atrial Fibrillation: 1-Year Outcome

BACKGROUND

CLOSE-guided pulmonary vein isolation (PVI) is based on contiguous and optimized (Ablation Index-guided) radiofrequency lesions. The efficacy of CLOSE-guided PVI in persistent atrial fibrillation (AF) treatment has been poorly evaluated.

METHODS

In two centers, 50 patients eligible for persistent AF ablation underwent CLOSE-guided PVI (Ablation Index ≥ 450 at the anterior wall, ≥300 at posterior wall, intertag distance ≤ 6 mm). If PVI failed to restore sinus rhythm (SR), electrical cardioversion (ECV) was performed. Atrial substrate modification (ASM) was performed only if PVI and ECV failed to restore SR. Recurrence was defined as any recorded episode of AF, atrial tachycardia (AT) or atrial flutter (AFL) > 30 s on Holter electrocardiographs at 3, 6 and 12 months.

RESULTS

From the 50 patients (64 ± 10 years, 14% long-standing persistent AF), SR was restored by ECV in 34 patients (68%) 56 ± 38 days prior to ablation. On the day of ablation, 42 patients (84%) were on class I-III anti-arrhythmic drug therapy (ADT) and the rhythm was AF in 23/50 patients. PVI was achieved in all patients; after PVI, ECV was required in 21 patients and ASM in 1 patient. The mean procedure time, radiofrequency time and fluoroscopy time were 141 ± 33 min, 23 ± 7 min and 7 ± 6 min, respectively. At 12 months, single-procedure freedom from AF/AT/AFL was 80%, with 19 patients (38%) receiving class I-III ADT.

CONCLUSIONS

In a population of patients with persistent AF monitored with intermittent cardiac rhythm recordings, CLOSE-guided PVI resulted in high single-procedure arrhythmia-free survival at 1 year. Future large-scale studies involving continuous cardiac monitoring are necessary.

Prevalence of amiodarone-induced hypothyroidism; A systematic review and meta-analysis

Amiodarone is a common anti-arrhythmic agent mostly used to treat and prevent different kinds of arrhythmia with several considerable side effects, most commonly on the thyroid gland. We aimed to assess the frequency of hypothyroidism among chronic amiodarone users. PubMed/Medline, Web of Science, and Scopus databases were screened in the title and abstract sections with no time limitation. Relevant published records reported amiodarone-induced hypothyroidism (AIH) among patients with normal thyroid function at baseline were recruited with further analysis according to gender and study locations. We found 29 records on 14143 individuals. Total population age ranged from 18 to 92 years (males: 58.2% (8158 out of 13,999)). The AIH prevalence was found to be 14% (95% confidence interval (CI): 12-17%). Further gender stratified showed an insignificant higher AIH frequency in females versus males (17%, 95% CI: 13-22% vs. 14%, 95% CI: 11-19% P= 0.304, respectively). Despite no significant difference in AIH prevalence according to different continents, African subjects had marginally lower AIH frequency compared to Asian (7%, 95% CI: 4-13% vs. 15%, 95% CI: 12-19%, P= 0.012) and South American persons (7%, 95% CI: 4-13% vs. 54%, 95% CI: 9-93%, P= 0.038). This review suggests the occurrence of AIH is quite considerable regardless of gender and area of residence, and several periodic thyroid assessment strategies should be developed for earlier recognition and therapeutic interventions in clinical settings.

Incidence of thyroid dysfunction following initiation of amiodarone treatment in patients with and without heart failure: a nationwide cohort study

AIMS

Thyroid dysfunction is considered the most frequent complication to amiodarone treatment, but data on its occurrence outside clinical trials are sparse. The present study aimed to examine the incidence of thyroid dysfunction following initiation of amiodarone treatment in a nationwide cohort of patients with and without heart failure (HF).

METHODS AND RESULTS

In Danish registries, we identified all patients with first-time amiodarone treatment during the period 2000-18, without prior thyroid disease or medication. The primary outcome was a composite of thyroid diagnoses and initiation of thyroid drugs. Outcomes were assessed at 1-year follow-up, and for patients free of events in the first year, in a landmark analysis for the subsequent 5 years. We included 43 724 patients with first-time amiodarone treatment, of whom 16 939 (38%) had HF. At 1-year follow-up, the cumulative incidence and adjusted hazard ratio (HR) of the primary outcome were 5.3% and 1.37 (95% confidence interval 1.25-1.50) in patients with a history of HF and 4.2% in those without HF (reference). In the 1-year landmark analysis, the subsequent 5-year cumulative incidences and adjusted HRs of the primary outcome were 5.3% (reference) in patients with 1-year accumulated dose <27.38 g [corresponding to average daily dose (ADD <75 mg)], 14.0% and HR 2.74 (2.46-3.05) for 27.38-45.63 g (ADD 75-125 mg), 20.0% and HR 4.16 (3.77-4.59) for 45.64-63.88 g (ADD 126-175 mg), and 24.5% and HR 5.30 (4.82-5.90) for >63.88 g (ADD >175 mg).

CONCLUSION

Among patients who initiated amiodarone treatment, around 5% had thyroid dysfunction at 1-year follow-up, with a slightly higher incidence in those with HF. A dose-response relationship was observed between the 1-year accumulated amiodarone dose and the subsequent 5-year cumulative incidence of thyroid dysfunction.

Amiodarone-induced muscle tremor in an elderly patient: A case report

BACKGROUND

Amiodarone is a Class III antiarrhythmic drug, which has been adopted for the treatment of atrial fibrillation and ventricular arrhythmia. However, the use of amiodarone can cause lower limb muscle tremors, which is recognized as a rare side effect of this medication.

CASE SUMMARY

An 84-year-old female was administrated with amiodarone for paroxysmal supraventricular tachycardia and frequent ventricular tachycardia. The patient developed a bilateral gastrocnemius tremor in the course of medication, and the strength of the patient’s bilateral knee flexor and extensor reached 4/5 and 3/5, respectively. After the use of amiodarone was stopped, and the patient was given a small dose of levetiracetam, the lower limb tremor symptoms were significantly mitigated, along with activity and function.

CONCLUSION

Attention should be paid to the significance of the side effects of drugs in the elderly, which may be atypical in the elderly. The relevant side effects of drugs may not be as rare as reported due to individual differences and different pharmacokinetics. If the side effects are generated, the medication should be adjusted in time, and the progress of the side effects should be intervened.

Clinical and Mechanistic Review of Amiodarone-Associated Optic Neuropathy

Amiodarone-associated optic neuropathy (AAON) is a complex clinical diagnosis, requiring distinction from non-arteritic ischemic optic neuropathy (NAION) due to a shared at-risk patient population. Diagnosis of AAON is complicated by a varied clinical presentation and incomplete pathophysiologic mechanisms. This article reviews pertinent literature for describing and clinically delineating AAON from NAION, as well as newly reported protective mechanisms of insulin-like growth factor 1 (IGF-1) and PI3K/Akt against amiodarone-induced oxidative and apoptotic injury in retinal ganglion and pigment epithelial cells. These studies offer a basis for exploring mechanisms of amiodarone toxicity in the optic nerve.

Myoclonic Jerks and Ataxia: A Case of Rare Neurological Side Effects of Amiodarone

We present the case of an 85-year-old man with a known medical history of recurrent ventricular arrhythmia and paroxysmal atrial fibrillation who was started on an amiodarone loading dose four days before presenting with tremors and balance impairment. Amiodarone's adverse effects in various systems have been well studied, although this is not the case with neurotoxic side effects. In this article, we discuss the neurotoxic side effects caused by amiodarone and the importance of a complete physical examination when starting this medication for supraventricular and ventricular arrhythmias.

CLInical Profile and Side Effects of chronic use of oral Amiodarone in cardiology outpatients department (CLIPSE-A Study)- A prospective observational study

Background

Amiodarone belongs to Class-III anti-arrhythmic drugs. It is one of the most effective anti-arrhythmic drugs used to treat or prevent several types of arrhythmias including atrial fibrillation, atrial flutter, ventricular tachycardia, and wide complex tachycardia, but unfortunately carries a high toxicity profile. Also, side effects of amiodarone involving various organs can be life-threatening.

Materials & methods

This was an observational study carried out for six months i.e from April to September. The study included patients who are on amiodarone for greater than or equal to six months. The required data was collected in-person from the case sheets, treatment charts, and by interviewing the patients. The data for 67 patients was documented in suitable data collection form for analysis.

Results

From our study data, it was noted that amiodarone was used for 3 different indications-atrial fibrillation, atrial flutter, and ventricular tachycardia. Among 67 patients enrolled, 38 had no side-effects. Side-effects data in the rest grouped basing on the organ system affected: 9 patients had renal effects, 6 patients had ophthalmic effects, 4 patients had endocrine effects, and 5 patients had hepatic effects.

Conclusion

From our study, it is concluded that amiodarone is a safe and effective anti-arrhythmic drug at lower doses i.e. 200-1100 mg/week. When treated in lower doses of 1400–2800 mg/week, many side effects have been incident. Although these effects are mild and develop only after prolonged usage of the drug, it should be used judiciously.

•

Amiodarone has an unusual spectrum of side effects with a prevalence of 15% in the first year, increasing up to 50% during long-term use.

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Our study demonstrated amiodarone does not produce significant side-effects when used in doses of 200–1100 mg/week.

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Few side-effects are observed when amiodarone is used in higher doses of 1200–2800 mg/week.

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When a side-effect is observed, mere reducing the dose or withdrawal of drug might help.

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In most of the cases of atrial fibrillation, amiodarone is discontinued or altered in first year of treatment basing on risk/benefit ratio.

Amiodarone-induced cutaneous leukocytoclastic vasculitis: a case report and a review of the literature

Amiodarone can be used in a variety of arrhythmias. Given its widespread use, the probability of clinicians encountering its cutaneous adverse effects is high. A few cases of amiodarone-induced cutaneous vasculitis were reported in the literature, probably because it is underdiagnosed in clinical practice. Indeed, amiodarone-related cutaneous reactions may present a wide range of manifestations and are sometimes difficult to diagnose. Herein, we report a case with a sizeable necrotic ulcer on the left lower leg shortly after amiodarone exposure. A rigorous diagnostic study was performed before concluding the diagnosis of amiodarone-induced cutaneous vasculitis, which showed the histopathological features of leukocytoclastic vasculitis. The lesion was almost completely healed by the third month of discontinuation of amiodarone. We did a literature search and found seven cases which were reported as leukocytoclastic or lymphocytic vasculitis. We reviewed previous cases and presented our case in comparison to prior cases.

Thyroid Dysfunction under Amiodarone in Patients with and without Congenital Heart Disease: Results of a Nationwide Analysis

Background: Amiodarone has a profound adverse toxicity profile. Large population-based analyses quantifying the risk of thyroid dysfunction (TD) in adults with and without congenital heart disease (ACHD) are lacking. Methods: All adults registered with a major German health insurer (≈9.2 million members) with amiodarone prescriptions were analyzed. Occurrence of amiodarone-associated TD was assessed. Results: Overall, 48,891 non-ACHD (37% female; median 73 years) and 886 ACHD (34% female; median 66 years) received amiodarone. Over 184,787 patient-years, 10,875 cases of TD occurred. The 10-year risk for TD was 38% in non-ACHD (35% ACHD). Within ACHD, compared to amiodarone-naïve patients, the hazard ratio (HR) for TD was 3.9 at 4 years after any amiodarone exposure. TD was associated with female gender (HR 1.42, p < 0.001) and younger age (HR 0.97 per 10 years, p = 0.009). Patients with congenital heart disease were not at increased risk (HR 0.98, p = 0.80). Diagnosis of complex congenital heart disease, however, was a predictor for TD (HR 1.56, p = 0.02). Amiodarone was continued in 47% of non-ACHD (38% ACHD), and 2.3% of non-ACHD (3.5% ACHD) underwent thyroid surgery/radiotherapy. Conclusions: Amiodarone-associated TD is common and comparable in non-ACHD and ACHD. While female gender and younger age are predictors for TD, congenital heart disease is not necessarily associated with an elevated risk.

A multicenter retrospective cohort study on predicting the risk for amiodarone pulmonary toxicity

BACKGROUND

Amiodarone is one of the most commonly used anti-arrhythmic agents. Amiodarone pulmonary toxicity is a potentially fatal adverse effect associated with amiodarone use. Previous studies on the epidemiology and risk factors for amiodarone pulmonary toxicity showed diverse results.

METHODS

A multicenter retrospective cohort study was conducted to identify clinic-epidemiologic markers associated with amiodarone pulmonary toxicity for development of a prediction rule. Patients taking amiodarone who were managed in 3 centres in Hong Kong from 2005 to 2015 were included in this study. Penalized logistic regression was used to model the outcome as it is rare.

RESULTS

A total of 34 cases with amiodarone pulmonary toxicity were identified among 1786 patients taking amiodarone for at least 90 days from 2005 to 2015. The incidence of amiodarone pulmonary toxicity was estimated to be 1.9%. The risk factors for amiodarone pulmonary toxicity included advanced age (OR 1.047, 95% CI 1.010-1.085, p = 0.013), ventricular arrhythmia (OR 2.703, 95% CI 1.053-6.935, p = 0.039), underlying lung disease (OR 2.511, 95% CI 1.146-5.501, p = 0.021) and cumulative dose of amiodarone (OR 4.762, 95% CI 1.310-17.309 p = 0.018).

CONCLUSIONS

The incidence of amiodarone pulmonary toxicity in Chinese patients in Hong Kong is estimated to be 1.9% in this study. Age, underlying lung disease, ventricular arrhythmia and cumulative dose of amiodarone are associated with the development of amiodarone pulmonary toxicity. A prediction rule was developed to inform the risk of developing amiodarone pulmonary toxicity.

Electrical cardioversion of atrial fibrillation and the risk of brady-arrhythmic events

BACKGROUND

Electrical cardioversion (ECV) is a common procedure for terminating atrial fibrillation (AF). ECV is associated with brady-arrhythmic events, however, the age-specific risks of clinically significant brady-arrhythmic events are unknown.

METHODS

Using Danish nationwide registers, we identified patients with AF at their first non-emergent ECV between 2005 and 2018 and estimated their 30-day risk of brady-arrhythmic events. Moreover, factors associated with increased risks of brady-arrhythmias were identified. Absolute risks were estimated using logistic regression models fitted with natural splines as well as standardization (G-formula).

RESULTS

We identified 20,725 eligible patients with a median age of 66 years (IQR 60-72) and most males (73%). The 30-day risks of brady-arrhythmic events after ECV were highly dependent on age with estimated risks ranging from 0.5% (95% CI 0.2-1.7) and 1.2% (95% CI 0.99-1.5) to 2.7% (95% CI 2.1-3.3) and 5.1% (95% CI 2.6-9.7) in patients aged 40, 65, 80, and 90 years, respectively. Factors associated with brady-arrhythmias were generally related to cardiovascular disease (eg, ischemic heart disease, heart failure, valvular AF) or a history of syncope. We found no indications that pre-treatment with anti-arrhythmic drugs conferred increased risks of brady-arrhythmic events (standardized absolute risk difference -0.25% [95% CI -0.67 to 0.17]).

CONCLUSIONS

ECV conferred clinically relevant 30-day risks of brady-arrhythmic events, especially in older patients. Anti-arrhythmic drug treatment was not found to increase the risk of brady-arrhythmias. Given the widespread use of ECV, these data should provide insights regarding the potential risks of brady-arrhythmic events.

Incidence of Post-Heart Transplant Chronic Thyroiditis and Its Association With Pretransplant Amiodarone Use

BACKGROUND

Chronic thyroiditis (CT) is a common cause of thyroid dysfunction and could therefore adversely affect outcomes in patients undergoing heart transplant (HT). The incidence of post-HT CT and whether amiodarone, a commonly used anti-arrhythmic drug in patients with heart failure during pre-HT period, is associated with the development of post-HT CT are unknown.

METHODS

A retrospective review of HT recipients from February 2, 2010 to October 16, 2018 was performed. Patients who lacked relevant pre-/post-HT records, underwent thyroidectomy, had pre-HT thyroid dysfunction or thyroiditis within 15 days post-HT, and those on amiodarone during the post-HT period were excluded, yielding a final cohort of 75 patients.

RESULTS

Patients had a mean age of 63.3 ± 1.4 years and were predominantly male (90.7%) and white (80%). The incidence of post-HT CT was 32% with the majority (83.3%) manifesting as hypothyroidism. Median time to diagnosis of CT after transplant was 10.2 months (interquartile range, 4-27.4). Additionally, the CT group had higher pre-HT use of amiodarone (non-CT vs CT: 21.6% vs 50%, P = .01), higher prevalence of atrial fibrillation (non-CT vs CT: 23.5% vs 45.8%; P = .05), and more stage IV/V chronic kidney disease (non-CT vs CT: 2% vs 16.7%, P = .02). On multivariate analysis, pre-HT amiodarone use was associated with the development of post-HT CT after adjustment for age, sex, and chronic kidney disease (odds ratio, 3.65; 95% CI, 1.17-11.44; P = .03).

CONCLUSION

The incidence of post-HT CT is high and is strongly associated with pre-HT amiodarone use underpinning the importance of closely following the post-HT thyroid profile in these patients.

Early pharmacologic conversion of atrial fibrillation after off-pump coronary artery bypass grafting

Background

The aim of this study was to evaluate the efficacy of early amiodarone-based pharmacological cardioversion for postoperative atrial fibrillation (POAF) following off-pump coronary bypass grafting (OPCAB).

Methods

A total of 507 patients who underwent OPCAB between 2015 and 2017 were categorized into POAF (n=94) and no-POAF (n=413) groups. Patients in the POAF group were treated according to the following institutional protocol: 150 mg loading dose of intravenous amiodarone, followed by oral administration with sequential maintenance doses at 600, 400, and 200 mg per day. If sinus rhythm was restored before discharge, patients were discharged without amiodarone or anticoagulants, except for dual antiplatelets.

Results

Before discharge at index hospitalization, 97.8% of POAF patients had restored sinus rhythm. Independent risk factors for POAF were age, unstable angina, prior percutaneous transluminal coronary angioplasty, and left atrial diameter. The mean follow-up duration was 41.1±12.8 months. Freedom from overall mortality and composite events, including mortality, major bleeding requiring admission and cerebrovascular events, were similar between the 2 groups. Results were consistent after propensity-score matching.

Conclusions

Amiodarone-based rapid pharmacological cardioversion of POAF resulted in a high sinus rhythm conversion rate (97.9%). Rate of late adverse cardiovascular events including stroke, were low even without anticoagulation. As optimal treatment and anticoagulation guidelines for POAF after OPCAB have not yet been established, amiodarone-based treatment protocols may be considered as a useful option.

Cost-Utility of Catheter Ablation for Atrial Fibrillation in Patients with Heart Failure: An Economic Evaluation

Background Recent trials comparing catheter ablation to medical therapy in patients with heart failure (HF) with symptomatic atrial fibrillation despite first-line management have demonstrated a reduction in adverse outcomes. We performed an economic evaluation to estimate the cost-utility of catheter ablation as second line therapy in patients with HF with reduced ejection fraction. Methods and Results A Markov model with health states of alive, dead, and alive with amiodarone toxicity was constructed, using the perspective of the Canadian healthcare payer. Patients in the alive states were at risk of HF and non-HF hospitalizations. Parameters were obtained from randomized trials and Alberta health system data for costs and outcomes. A lifetime time horizon was adopted, with discounting at 3.0% annually. Probabilistic and 1-way sensitivity analyses were performed. Costs are reported in 2018 Canadian dollars. A patient treated with catheter ablation experienced lifetime costs of $64 960 and 5.63 quality-adjusted life-years (QALY), compared with $49 865 and 5.18 QALYs for medical treatment. The incremental cost-effectiveness ratio was $35 360/QALY (95% CI, $21 518-77 419), with a 90% chance of being cost-effective at a willingness-to-pay threshold of $50 000/QALY. A minimum mortality reduction of 28%, or a minimum duration of benefit of >1 to 2 years was required for catheter ablation to be attractive at this threshold. Conclusions Catheter ablation is likely to be cost-effective as a second line intervention for patients with HF with symptomatic atrial fibrillation, with incremental cost-effectiveness ratio $35 360/QALY, as long as over half of the relative mortality benefit observed in extant trials is borne out in future studies.

Current Drug Treatment Strategies for Atrial Fibrillation and TASK-1 Inhibition as an Emerging Novel Therapy Option

Atrial fibrillation (AF) is the most common sustained arrhythmia with a prevalence of up to 4% and an upwards trend due to demographic changes. It is associated with an increase in mortality and stroke incidences. While stroke risk can be significantly reduced through anticoagulant therapy, adequate treatment of other AF related symptoms remains an unmet medical need in many cases. Two main treatment strategies are available: rate control that modulates ventricular heart rate and prevents tachymyopathy as well as rhythm control that aims to restore and sustain sinus rhythm. Rate control can be achieved through drugs or ablation of the atrioventricular node, rendering the patient pacemaker-dependent. For rhythm control electrical cardioversion and pharmacological cardioversion can be used. While electrical cardioversion requires fasting and sedation of the patient, antiarrhythmic drugs have other limitations. Most antiarrhythmic drugs carry a risk for pro-arrhythmic effects and are contraindicated in patients with structural heart diseases. Furthermore, catheter ablation of pulmonary veins can be performed with its risk of intraprocedural complications and varying success. In recent years TASK-1 has been introduced as a new target for AF therapy. Upregulation of TASK-1 in AF patients contributes to prolongation of the action potential duration. In a porcine model of AF, TASK-1 inhibition by gene therapy or pharmacological compounds induced cardioversion to sinus rhythm. The DOxapram Conversion TO Sinus rhythm (DOCTOS)-Trial will reveal whether doxapram, a potent TASK-1 inhibitor, can be used for acute cardioversion of persistent and paroxysmal AF in patients, potentially leading to a new treatment option for AF.

Pharmacological Cardioversion after Pre-Treatment with Antiarrythmic Drugs Prior to Electrical Cardioversion in Persistent Atrial Fibrillation: Impact on Maintenance of Sinus Rhythm

BACKGROUND

Antiarrhythmic drugs (AADs) are frequently initiated in patients with persistent atrial fibrillation (AF) prior to electrical cardioversion (ECV), achieving pharmacological cardioversion (PCV) in some cases. Little is known about the mode of cardioversion and the effect of the type of AAD used in the maintenance of sinus rhythm (SR).

METHODS

From three national surveys of patients with persistent AF referred for ECV, we selected those who were pre-treated with AADs (amiodarone or group Ic AADs). We analyzed the effect of the type of cardioversion (pharmacological vs. electrical) and the AAD used in the maintenance of SR at three months.

RESULTS

Among the 665 patients selected, 151 had a successful PCV prior to the planned ECV. In the remaining 514 patients, 460 had a successful ECV. A successful PCV was related to a higher rate of SR maintenance than a successful ECV (77.9% vs. 57.5%; p < 0.0001). After a successful PCV, the maintenance of SR was identical in those patients treated with amiodarone and those treated with group Ic AADs (77.4% vs. 77.5%; p = 0.99), whereas after a successful ECV, amiodarone was clearly superior to group Ic AADs (61.3% vs. 43.0%; p = 0.001). Considering patients with successful PCV and ECV together, PCV was an independent factor related to the maintenance of SR.

CONCLUSIONS

In patients with persistent AF, successful PCV selects a subgroup with a high probability of maintenance of SR. With regard to drugs, amiodarone was superior to group Ic AADs in patients with ECV, whereas in PCV, no differences were observed.

Insights from advancements and pathbreaking research on the minimally invasive treatment of atrial fibrillation

Atrial fibrillation (AF) remains the most common cardiac arrhythmia with increasing prevalence in developed and aging countries. Pharmacological antiarrhythmic therapy has low effectiveness and is limited by its toxicity. Developed in 1987 by James Cox surgical ablation of AF called MAZE procedure was very effective, but due to its invasiveness and complexity was not widely adopted. Landmark research done by Haissaguerre in 1998 initiated a new approach for treatment namely percutaneous catheter ablation, which remains a class I/A indication in symptomatic paroxysmal AF refractory to optimal medical therapy. However, its efficacy in patients with persistent atrial fibrillation (PSAF) is far from satisfactory. Recent advancements in devices and techniques of minimally invasive surgical ablation show very good results in the treatment of PSAF. Current guidelines equate surgical with catheter ablation within the scope of efficacy indicating that both may be considered as an effective and safe treatment option for patients with persistent forms of arrhythmia. The higher efficacy of surgical ablation was confirmed at a 7-year follow-up of FAST trial with recurrence rate as high as 87% in catheter arm compared with 56% in thoracoscopic ablation arm. A new concept of the invasive treatment of AF consisting of combined surgical (epicardial) and electrophysiological (endocardial) was introduced in 2009. Recently experts' opinions and published data suggest that the proper hybrid treatment consisting of a planned combination of surgical and catheter ablation may give even better results. One of the most invaluable benefits of surgical ablations is the possibility of concomitant occlusion of the left atrial appendage. Recently good results have been reported for the novel epicardial clip for closing the left atrial appendage, which is placed in the deployment loop on a disposable holder.

Neurological complications of cardiovascular drugs

Cardiovascular drugs are used to treat arterial hypertension, hyperlipidemia, arrhythmias, heart failure, and coronary artery disease. They also include antiplatelet and anticoagulant drugs that are essential for prevention of cardiogenic embolism. Most neurologic complications of the cardiovascular drugs are minor or transient and are far outweighed by the anticipated benefits of treatment. Other neurologic complications are more serious and require early recognition and management. Overtreatment of arterial hypertension may cause lightheadedness or fatigue but often responds readily to dose adjustment or an alternative drug. Other drug complications may be more troublesome as in myalgia associated with statins or headache associated with vasodilators. The recognized bleeding risk of the antithrombotics requires careful calculation of risk/benefit ratios for individual patients. Many neurologic complications of cardiovascular drugs are well documented in clinical trials with known frequency and severity, but others are rare and recognized only in isolated case reports or small case series. This chapter draws on both sources to report the adverse effects on muscle, nerve, and brain associated with commonly used cardiovascular drugs.

Transient bilateral chorea secondary to digoxin toxicity in a female with acute kidney injury: a case report

Background

Chorea secondary to digoxin toxicity is rare, with only three published cases describing the phenomenon. We report the case of a 78-year-old female presenting with intermittent vomiting and diarrhoea for 4 weeks. She had a history of chronic kidney disease and digoxin use for atrial fibrillation.

Case summary

A 78-year-old lady presented to the emergency department with a 4-week history of intermittent vomiting and diarrhoea. These symptoms commenced after a course of antibiotics prescribed by her general practitioner for a urinary tract infection. Her admission electrocardiogram demonstrated atrial fibrillation at a rate of 32, with evidence of digitalis toxicity. Her creatinine was 396 µmol/L (44–80 µmol/L) with digoxin level 8.1 nmol/L (0.77–1.5 nmol/L). Initially, treatment was with digoxin-specific antibody (FAB) and fluid resuscitation. Within 24 h, she developed transient head, neck, and bilateral upper limb chorea. Review of medications revealed no other likely causative agent. Neuroimaging showed no new ischaemia, but stable established bilateral infarcts of the basal ganglia. Haloperidol 0.5 mg twice daily was commenced. Three days later as digoxin levels normalized, the chorea resolved entirely without recurrence.

Discussion

We have identified three reported cases of digoxin-induced chorea. Our case resembles two of the published cases where a transient bilateral chorea, associated with digitalis toxicity and resolving within a few days of normalization of digoxin levels was demonstrated. There were no other focal neurological signs or symptoms. It has been postulated that an alteration to dopaminergic neuronal activity is a potential mechanism, as digoxin also demonstrates neuropsychiatric side effects such as psychosis and depression.

Management of tachyarrhythmias in pregnancy - A review

The most common arrhythmias detected during pregnancy include sinus tachycardia, sinus bradycardia, and sinus arrhythmia, identified in 0.1% of pregnancies. Isolated premature atrial or ventricular arrhythmias are observed in 0.03% of pregnancies. Arrhythmias may become more frequent during pregnancy or may manifest for the first time.

Optimal Timing of VT Ablation for Patients with ICD Therapies

Purpose of Review

Optimal timing for catheter ablation of ventricular tachycardia is an important yet unresolved subject. While it is clear that it is indicated with relatively advanced disease, it is still uncertain how early it should be recommended. In this review, we will focus on the status of timing of catheter ablation for VT in patients with ICD therapies.

Recent Findings

The latest expert consensus statement added a new timing indication for catheter ablation after the first episode of monomorphic VT, in patients with ischemic heart disease and an ICD.

Summary

Early referral for catheter ablation reduces the number of VT recurrences; however, an impact on mortality has not been demonstrated yet. Guidelines and real-world data alike show an increasing trend to refer patients after the first VT episode in ICD patients. Randomized clinical trials powered to assess mortality are essential in order confirm the beneficial effects of an early strategy.

Low-dose Amiodarone Is Safe: A Systematic Review and Meta-analysis

Amiodarone is commonly used for a variety of arrhythmias and, in some parts of the world, is the only available antiarrhythmic drug (AAD). Yet, amiodarone is known to have a wide range of potential side effects, many of which are dose- and duration-dependent. We sought to study the incidence of side effects leading to the discontinuation of low-dose amiodarone, arbitrarily defined as 200 mg/day or less, and very-low-dose amiodarone, defined as 100 mg/day or less. In this study, literature databases were searched through June 2019. Studies that reported the incidence or prevalence of side effects of amiodarone were included. Effect estimates from individual studies were extracted and combined using the random-effects generic inverse variance method of DerSimonian and Laird. A total of 10 observational cohort studies involving 901 patients were included in the analysis. The pooled estimated incidence of overall side effects for low-dose amiodarone was 0.17 [95% confidence interval (CI): 0.12–0.22]. In addition, the pooled estimated incidence of side effects requiring medication discontinuation was 0.06 (95% CI: 0.03–0.11). As compared with 200 mg/day of amiodarone, the pooled estimated incidence of overall side effects was 0.11 (95% CI: 0.04–0.27), while the incidence of side effects requiring medication discontinuation was 0.02 (95% CI: 0.01–0.06) for the dose of 100 mg/day. In conclusion, very-low-dose amiodarone displays a low incidence of significant side effects requiring medication discontinuation.

Atrial fibrillation ablation in heart failure

Atrial fibrillation (AF) and heart failure (HF) commonly coexist in the same patient and either condition predisposes to the other. Several mechanisms promote the pathophysiological relationship between AF and HF, reducing quality of life, increasing the risk of stroke, and worsening HF progression. Although restoration and maintenance of sinus rhythm would be ideal for those patients, several trials comparing rhythm and rate control failed to show a benefit of rhythm control strategy, achieved with pharmacological therapy, in terms of hospitalization for HF or death. Catheter ablation is a well-established option for symptomatic AF patients, resistant to drug therapy, with normal cardiac function. Several recent studies have shown an improvement in clinical outcomes after AF ablation in HF patients highlighting the emerging role of the invasive approach in this subset of patients. However, several concerns regarding patients’ selection and standardization of the procedure still remain to be addressed.

Frequent Offenders and Patterns of Injury

Given the liver's role in drug metabolism, it is uniquely sensitive to potential drug-induced liver injury (DILI) despite inherent protective mechanisms. In this article, we focus on the most common causes of DILI and their patterns of injury. Although not comprehensive, we attempt to cover several classes of commonly used drugs, and their associated patterns of injury and management.

Inverse Association between Metformin and Amiodarone-Associated Extracardiac Adverse Events

Background: The association between metformin and amiodarone-induced adverse events was examined using spontaneous adverse event database. Additionally, the association between other antidiabetic drugs and amiodarone-induced adverse events were also examined. Methods: A total of 6,153,696 reports from the first quarter of 2004 through the fourth quarter of 2015 were downloaded from the US Food and Drug Administration adverse event reporting system. Reporting odds ratio (ROR) and information component (IC) were used to detect associations between antidiabetic drugs and amiodarone-associated adverse events. Additionally, subset data analysis was performed to investigate whether the use of antidiabetic drugs further increased or decreased the risk of adverse events in patients receiving amiodarone therapy. Next, the RORs were adjusted for coadministered antidiabetic drugs using logistic regression analysis. Results: By whole dataset analysis, significant inverse associations were found between metformin and interstitial lung disease (ROR 0.84, 95% confidence interval [CI] 0.79-0.90; IC -0.24, 95% CI -0.33 to -0.15). In the subset data analysis, metformin (ROR 0.62, 95%CI 0.43-0.89; IC -0.63, 95%CI -1.14 to -0.11), sulfonylureas (ROR 0.53, 95%CI 0.32-0.85; IC -0.85, 95%CI -1.53 to -0.17), and dipeptidyl peptidase-4 (DPP-4) inhibitors (ROR 0.25, 95%CI 0.08-0.78; IC -1.66, 95%CI -3.08 to -0.23) were inversely associated with hyperthyroidism. Additionally, metformin (ROR 0.43, 95%CI 0.33-0.57; IC -1.09, 95%CI -1.49 to -0.69), sulfonylureas (ROR 0.64, 95%CI 0.48-0.86; IC -0.59, 95%CI -1.00 to -0.17), and DPP-4 inhibitors (ROR 0.47, 95%CI 0.27-0.81; IC -0.99, 95%CI -1.76 to -0.22) were inversely associated with interstitial lung disease. In the logistic regression analyses, DPP-4 inhibitors (adjusted ROR 0.32, 95% CI 0.10-1.00) and metformin (adjusted ROR 0.46, 95% CI 0.34-0.62) were inversely associated with amiodarone-associated hyperthyroidism and interstitial lung disease, respectively. Conclusion: Metformin is a candidate drug to reduce the risk of amiodarone-induced hyperthyroidism and interstitial lung disease.

Drugs Repurposing in High-Grade Serous Ovarian Cancer

BACKGROUND

Ovary Carcinoma (OC) is the most lethal gynecological neoplasm due to the late diagnoses and to the common development of resistance to platinum-based chemotherapy. Thus, novel therapeutic approaches are urgently required. In this regard, the strategy of drug repurposing is becoming attractive. By this approach, the effectiveness of a drug originally developed for another indication is tested in a different pathology. The advantage is that data about pharmacokinetic properties and toxicity are already available. Thus, in principle, it is possible to reduce research costs and to speed up drug usage/marketing.

RESULTS

Here, some noticeable examples of repurposed drugs for OC, such as amiodarone, ruxolitinib, statins, disulfiram, ormeloxifenem, and Quinacrine, are reported. Amiodarone, an antiarrhythmic agent, has shown promising anti-OC activity, although the systemic toxicity should not be neglected. The JAK inhibitor, Ruxolitinib, may be employed particularly in coadministration with standard OC therapy as it synergistically interacts with platinum-based drugs. Particularly interesting is the use of statin which represent one of the most commonly administered drugs in aged population to treat hypercholesterolemia. Disulfiram, employed in the treatment of chronic alcoholism, has shown anti-OC properties. Ormeloxifene, commonly used for contraception, seems to be promising, especially due to the negligible side effects. Finally, Quinacrine used as an antimicrobial and anti-inflammatory drug, is able to downregulate OC cell growth and promote cell death.

CONCLUSION

Whereas further testing in patients are necessary to better clarify the therapeutic potential of repurposed drugs for OC, it is believed that their use, better if combined with OC targeted delivery systems, can significantly contribute to the development of novel and effective anti-OC treatments.

The role of amiodarone in contemporary management of complex cardiac arrhythmias

Amiodarone is an iodinated benzofuran derivative, a highly lipophilic drug with unpredictable pharmacokinetics. Although originally classified as a class III agent due to its ability to prolong refractoriness in cardiac regions and prevent/terminate re-entry, amiodarone shows antiarrhythmic properties of all four antiarrhythmic drug classes. Amiodarone is a potent coronary and peripheral vasodilator and can be safely used in patients with left ventricular dysfunction after myocardial infarction or those with congestive heart failure or hypertrophic cardiomyopathy. Its use is regularly accompanied with QT and QTc-interval prolongation but rarely with ventricular proarrhythmia. It is the most powerful pharmacological agent for long-term sinus rhythm maintenance in patients with atrial fibrillation. Amiodarone, particularly if co-administered with beta-blockers, reduces the rate of arrhythmic death due to ventricular tachyarrhythmias in patients with heart failure, but its benefit on cardiovascular and overall survival in these patients is uncertain. In addition, amiodarone is an important adjuvant drug for the reduction of shocks in patients with an implantable cardioverter-defibrillator. Over the past 40 years, amiodarone became the most prescribed antiarrhythmic. Nevertheless, the slow onset of its antiarrhythmic action requires a loading dose while the high risk of non-cardiac toxicity and common drug-drug interactions limit its long-term use. Furthermore patients treated with amiodarone require a close supervision by the treating physician. Therefore amiodarone is generally considered a secondary therapeutic option. Long-term treatment with amiodarone should be based on the use of minimal doses for satisfactory arrhythmia outcome and serial screening for thyroid, liver and pulmonary toxicity.

Amiodarone in the aged

Amiodarone is a highly effective antiarrhythmic drug, but can have serious adverse effects, particularly in older patients. If possible it should not be used purely for controlling the heart rate

If a prescription for amiodarone is contemplated, particularly for an older patient, consult a cardiologist. Avoid amiodarone in patients with significant conduction system disease, significant liver or pulmonary disease, or hyperthyroidism

Regular monitoring of the patient, clinically and biochemically, is required to identify complications at an early, treatable stage. Maintain a high level of suspicion if a patient taking amiodarone is experiencing adverse reactions and presents with new symptoms

Consider potential drug interactions when other drugs are prescribed with amiodarone. The effects and toxicities of amiodarone may persist weeks after it is stopped

Amiodarone and thyroid physiology, pathophysiology, diagnosis and management

Although amiodarone is considered the most effective antiarrhythmic agent, its use is limited by a wide variety of potential toxicities. The purpose of this review is to provide a comprehensive "bench to bedside" overview of the ways amiodarone influences thyroid function. We performed a systematic search of MEDLINE to identify peer-reviewed clinical trials, randomized controlled trials, meta-analyses, and other clinically relevant studies. The search was limited to English-language reports published between 1950 and 2017. Amiodarone was searched using the terms adverse effects, hypothyroidism, myxedema, hyperthyroidism, thyroid storm, atrial fibrillation, ventricular arrhythmia, and electrical storm. Google and Google scholar as well as bibliographies of identified articles were reviewed for additional references. We included 163 germane references in this review. Because amiodarone is one of the most frequently prescribed antiarrhythmic drugs in the United States, the mechanistic, diagnostic and therapeutic information provided is relevant for practicing clinicians in a wide range of medical specialties.