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Lancet (London, England) Aug 2016Hyperthyroidism is characterised by increased thyroid hormone synthesis and secretion from the thyroid gland, whereas thyrotoxicosis refers to the clinical syndrome of... (Review)
Review
Hyperthyroidism is characterised by increased thyroid hormone synthesis and secretion from the thyroid gland, whereas thyrotoxicosis refers to the clinical syndrome of excess circulating thyroid hormones, irrespective of the source. The most common cause of hyperthyroidism is Graves' disease, followed by toxic nodular goitre. Other important causes of thyrotoxicosis include thyroiditis, iodine-induced and drug-induced thyroid dysfunction, and factitious ingestion of excess thyroid hormones. Treatment options for Graves' disease include antithyroid drugs, radioactive iodine therapy, and surgery, whereas antithyroid drugs are not generally used long term in toxic nodular goitre, because of the high relapse rate of thyrotoxicosis after discontinuation. β blockers are used in symptomatic thyrotoxicosis, and might be the only treatment needed for thyrotoxicosis not caused by excessive production and release of the thyroid hormones. Thyroid storm and hyperthyroidism in pregnancy and during the post-partum period are special circumstances that need careful assessment and treatment.
Topics: Adrenergic beta-Antagonists; Amiodarone; Antithyroid Agents; Diagnosis, Differential; Drug Administration Schedule; Female; Graves Disease; Humans; Hyperthyroidism; Iodine Radioisotopes; Patient Care Team; Practice Guidelines as Topic; Pregnancy; Pregnancy Complications; Risk Factors; Thyroid Crisis; Thyroid Gland; Thyroid Hormones; Thyroidectomy; Thyrotoxicosis
PubMed: 27038492
DOI: 10.1016/S0140-6736(16)00278-6 -
American Journal of Health-system... Apr 2021The current evidence regarding iodine-containing compounds and iodine allergy cross-reactivity is reviewed. (Review)
Review
PURPOSE
The current evidence regarding iodine-containing compounds and iodine allergy cross-reactivity is reviewed.
SUMMARY
Iodine is an essential human nutrient found in the thyroid gland. It is used in the synthesis of the thyroid hormones thyroxine and triiodothyroxine. Patients who report having adverse reactions to iodine-containing substances are often labelled as having an "iodine allergy," which can result in delays in care or patients being denied essential iodinated contrast media (ICM) or other iodine-containing drugs. A literature review was conducted to evaluate the evidence regarding iodine allergy and iodine-containing drugs. Of 435 articles considered potentially appropriate for full review (plus 12 additional articles included on the basis of references from the eligible articles), 113 could not be obtained. After exclusion of 353 articles that did not meet all inclusion criteria, the remaining 81 articles were included in the review. The results of the literature review indicated that iodine has not been shown to be the allergen responsible for allergic reactions to iodinated contrast media, amiodarone, povidone-iodine, and other iodine-containing compounds.
CONCLUSION
There is a lack of evidence to support cross-reactivity between iodine-containing compounds in so called iodine-allergic individuals.
Topics: Amiodarone; Contrast Media; Drug Hypersensitivity; Humans; Iodine; Thyroxine
PubMed: 33547463
DOI: 10.1093/ajhp/zxab033 -
Acta Clinica Croatica Aug 2022Thyroid gland has a key role in maintaining the body homeostasis. Thyroxine is the main hormone secreted from the thyroid gland, its effect being predominantly achieved... (Review)
Review
Thyroid gland has a key role in maintaining the body homeostasis. Thyroxine is the main hormone secreted from the thyroid gland, its effect being predominantly achieved after the intracellular conversion of thyroxine to triiodothyronine, which exhibits a higher affinity for the receptor complex, thus modifying gene expression of the target cells. Amiodarone is one of the most commonly used antiarrhythmics in the treatment of a broad spectrum of arrhythmias, usually tachyarrhythmias. Amiodarone contains a large proportion of iodine, which is, in addition to the intrinsic effect of the medication, the basis of the impact on thyroid function. It is believed that 15%-20% of patients treated with amiodarone develop some form of thyroid dysfunction. Amiodarone may cause amiodarone-induced hypothyroidism (AIH) or amiodarone-induced thyrotoxicosis (AIT). AIT is usually developed in the areas with too low uptake of iodine, while AIH is developed in the areas where there is a sufficient iodine uptake. Type 1 AIT is more common among patients with an underlying thyroid pathology, such as nodular goiter or Graves' (Basedow's) disease, while type 2 mostly develops in a previously healthy thyroid. AIH is more common in patients with previously diagnosed Hashimoto's thyroiditis. Combined types of the diseases have also been described. Patients treated with amiodarone should be monitored regularly, including laboratory testing and clinical examinations, to early detect any deviations in the functioning of the thyroid gland. Supplementary levothyroxine therapy is the basis of AIH treatment. In such cases, amiodarone therapy quite often need not be discontinued. Type 1 AIT is treated with thyrostatic agents, like any other type of thyrotoxicosis. If possible, the underlying amiodarone therapy should be discontinued. In contrast to type 1 AIT, the basic pathophysiological substrate of which is the increased synthesis and release of thyroid hormones, the basis of type 2 AIT is destructive thyroiditis caused by amiodarone, desethylamiodarone as its main metabolite, and an increased iodine uptake. Glucocorticoid therapy is the basis of treatment for this type of disease.
Topics: Humans; Amiodarone; Thyroxine; Hypothyroidism; Thyrotoxicosis; Thyroiditis; Iodine
PubMed: 36818930
DOI: 10.20471/acc.2022.61.02.20 -
Trends in Cardiovascular Medicine Jul 2019Although 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...
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.
Topics: Amiodarone; Animals; Anti-Arrhythmia Agents; Humans; Predictive Value of Tests; Prognosis; Risk Assessment; Thyroid Diseases; Thyroid Function Tests; Thyroid Gland
PubMed: 30309693
DOI: 10.1016/j.tcm.2018.09.005 -
European Heart Journal May 2017Intravenous procainamide and amiodarone are drugs of choice for well-tolerated ventricular tachycardia. However, the choice between them, even according to Guidelines,... (Comparative Study)
Comparative Study Randomized Controlled Trial
AIMS
Intravenous procainamide and amiodarone are drugs of choice for well-tolerated ventricular tachycardia. However, the choice between them, even according to Guidelines, is unclear. We performed a multicentre randomized open-labelled study to determine the safety and efficacy of intravenous procainamide and amiodarone for the acute treatment of tolerated wide QRS complex (probably ventricular) tachycardia.
METHODS AND RESULTS
Patients were randomly assigned to receive intravenous procainamide (10 mg/kg/20 min) or amiodarone (5 mg/kg/20 min). The primary endpoint was the incidence of major predefined cardiac adverse events within 40 min after infusion initiation. Of 74 patients included, 62 could be analysed. The primary endpoint occurred in 3 of 33 (9%) procainamide and 12 of 29 (41%) amiodarone patients (odd ratio, OR = 0.1; 95% confidence interval, CI 0.03-0.6; P = 0.006). Tachycardia terminated within 40 min in 22 (67%) procainamide and 11 (38%) amiodarone patients (OR = 3.3; 95% CI 1.2-9.3; P = 0.026). In the following 24 h, adverse events occurred in 18% procainamide and 31% amiodarone patients (OR: 0.49; 95% CI: 0.15-1.61; P: 0.24). Among 49 patients with structural heart disease, the primary endpoint was less common in procainamide patients (3 [11%] vs. 10 [43%]; OR: 0.17; 95% CI: 0.04-0.73, P = 0.017).
CONCLUSIONS
This study compares for the first time in a randomized design intravenous procainamide and amiodarone for the treatment of the acute episode of sustained monomorphic well-tolerated (probably) ventricular tachycardia. Procainamide therapy was associated with less major cardiac adverse events and a higher proportion of tachycardia termination within 40 min.
Topics: Aged; Amiodarone; Anti-Arrhythmia Agents; Cardiomyopathies; Drug Administration Schedule; Female; Humans; Infusions, Intravenous; Male; Middle Aged; Patient Selection; Procainamide; Tachycardia, Ventricular; Treatment Outcome
PubMed: 27354046
DOI: 10.1093/eurheartj/ehw230 -
Critical Care (London, England) Jul 2021New-onset atrial fibrillation (NOAF) in patients treated on an intensive care unit (ICU) is common and associated with significant morbidity and mortality. We undertook... (Review)
Review
BACKGROUND
New-onset atrial fibrillation (NOAF) in patients treated on an intensive care unit (ICU) is common and associated with significant morbidity and mortality. We undertook a systematic scoping review to summarise comparative evidence to inform NOAF management for patients admitted to ICU.
METHODS
We searched MEDLINE, EMBASE, CINAHL, Web of Science, OpenGrey, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effects, ISRCTN, ClinicalTrials.gov, EU Clinical Trials register, additional WHO ICTRP trial databases, and NIHR Clinical Trials Gateway in March 2019. We included studies evaluating treatment or prevention strategies for NOAF or acute anticoagulation in general medical, surgical or mixed adult ICUs. We extracted study details, population characteristics, intervention and comparator(s), methods addressing confounding, results, and recommendations for future research onto study-specific forms.
RESULTS
Of 3,651 citations, 42 articles were eligible: 25 primary studies, 12 review articles and 5 surveys/opinion papers. Definitions of NOAF varied between NOAF lasting 30 s to NOAF lasting > 24 h. Only one comparative study investigated effects of anticoagulation. Evidence from small RCTs suggests calcium channel blockers (CCBs) result in slower rhythm control than beta blockers (1 study), and more cardiovascular instability than amiodarone (1 study). Evidence from 4 non-randomised studies suggests beta blocker and amiodarone therapy may be equivalent in respect to rhythm control. Beta blockers may be associated with improved survival compared to amiodarone, CCBs, and digoxin, though supporting evidence is subject to confounding. Currently, the limited evidence does not support therapeutic anticoagulation during ICU admission.
CONCLUSIONS
From the limited evidence available beta blockers or amiodarone may be superior to CCBs as first line therapy in undifferentiated patients in ICU. The little evidence available does not support therapeutic anticoagulation for NOAF whilst patients are critically ill. Consensus definitions for NOAF, rate and rhythm control are needed.
Topics: Adrenergic beta-Antagonists; Amiodarone; Anti-Arrhythmia Agents; Atrial Fibrillation; Calcium Channel Blockers; Humans; Intensive Care Units; Risk Factors; Time Factors
PubMed: 34289899
DOI: 10.1186/s13054-021-03684-5 -
Journal of Veterinary Internal Medicine 2023Erroneous thyroid function test results can occur because of drugs that alter thyroid hormone physiology in one or more aspects, including synthesis, secretion,... (Review)
Review
Erroneous thyroid function test results can occur because of drugs that alter thyroid hormone physiology in one or more aspects, including synthesis, secretion, distribution, and metabolism. Research since publication of the last review in the Journal of Veterinary Internal Medicine (JVIM) 20 years ago has evaluated the effects of amiodarone, zonisamide, inhalant anesthetics, clomipramine, trilostane, and toceranib on thyroid function tests in the dog. In addition, recent work on the effects of glucocorticoids, sulfonamides, phenobarbital, and nonsteroidal anti-inflammatory drugs will be reviewed. Awareness of these effects is necessary to avoid misdiagnosis of hypothyroidism and unnecessary treatment.
Topics: Dogs; Animals; Thyroid Function Tests; Hypothyroidism; Thyroid Hormones; Amiodarone; Anti-Arrhythmia Agents; Dog Diseases
PubMed: 37498128
DOI: 10.1111/jvim.16823 -
The New England Journal of Medicine May 2016Antiarrhythmic drugs are used commonly in out-of-hospital cardiac arrest for shock-refractory ventricular fibrillation or pulseless ventricular tachycardia, but without... (Comparative Study)
Comparative Study Randomized Controlled Trial
BACKGROUND
Antiarrhythmic drugs are used commonly in out-of-hospital cardiac arrest for shock-refractory ventricular fibrillation or pulseless ventricular tachycardia, but without proven survival benefit.
METHODS
In this randomized, double-blind trial, we compared parenteral amiodarone, lidocaine, and saline placebo, along with standard care, in adults who had nontraumatic out-of-hospital cardiac arrest, shock-refractory ventricular fibrillation or pulseless ventricular tachycardia after at least one shock, and vascular access. Paramedics enrolled patients at 10 North American sites. The primary outcome was survival to hospital discharge; the secondary outcome was favorable neurologic function at discharge. The per-protocol (primary analysis) population included all randomly assigned participants who met eligibility criteria and received any dose of a trial drug and whose initial cardiac-arrest rhythm of ventricular fibrillation or pulseless ventricular tachycardia was refractory to shock.
RESULTS
In the per-protocol population, 3026 patients were randomly assigned to amiodarone (974), lidocaine (993), or placebo (1059); of those, 24.4%, 23.7%, and 21.0%, respectively, survived to hospital discharge. The difference in survival rate for amiodarone versus placebo was 3.2 percentage points (95% confidence interval [CI], -0.4 to 7.0; P=0.08); for lidocaine versus placebo, 2.6 percentage points (95% CI, -1.0 to 6.3; P=0.16); and for amiodarone versus lidocaine, 0.7 percentage points (95% CI, -3.2 to 4.7; P=0.70). Neurologic outcome at discharge was similar in the three groups. There was heterogeneity of treatment effect with respect to whether the arrest was witnessed (P=0.05); active drugs were associated with a survival rate that was significantly higher than the rate with placebo among patients with bystander-witnessed arrest but not among those with unwitnessed arrest. More amiodarone recipients required temporary cardiac pacing than did recipients of lidocaine or placebo.
CONCLUSIONS
Overall, neither amiodarone nor lidocaine resulted in a significantly higher rate of survival or favorable neurologic outcome than the rate with placebo among patients with out-of-hospital cardiac arrest due to initial shock-refractory ventricular fibrillation or pulseless ventricular tachycardia. (Funded by the National Heart, Lung, and Blood Institute and others; ClinicalTrials.gov number, NCT01401647.).
Topics: Adult; Aged; Amiodarone; Anti-Arrhythmia Agents; Cardiopulmonary Resuscitation; Central Nervous System Diseases; Combined Modality Therapy; Double-Blind Method; Electric Countershock; Emergency Medical Services; Female; Humans; Intention to Treat Analysis; Lidocaine; Male; Middle Aged; Out-of-Hospital Cardiac Arrest; Patient Discharge; Survival Rate; Tachycardia, Ventricular; Ventricular Fibrillation
PubMed: 27043165
DOI: 10.1056/NEJMoa1514204 -
Cell Dec 2022Drug-drug interaction of the antiviral sofosbuvir and the antiarrhythmics amiodarone has been reported to cause fatal heartbeat slowing. Sofosbuvir and its analog,...
Drug-drug interaction of the antiviral sofosbuvir and the antiarrhythmics amiodarone has been reported to cause fatal heartbeat slowing. Sofosbuvir and its analog, MNI-1, were reported to potentiate the inhibition of cardiomyocyte calcium handling by amiodarone, which functions as a multi-channel antagonist, and implicate its inhibitory effect on L-type Ca channels, but the molecular mechanism has remained unclear. Here we present systematic cryo-EM structural analysis of Ca1.1 and Ca1.3 treated with amiodarone or sofosbuvir alone, or sofosbuvir/MNI-1 combined with amiodarone. Whereas amiodarone alone occupies the dihydropyridine binding site, sofosbuvir is not found in the channel when applied on its own. In the presence of amiodarone, sofosbuvir/MNI-1 is anchored in the central cavity of the pore domain through specific interaction with amiodarone and directly obstructs the ion permeation path. Our study reveals the molecular basis for the physical, pharmacodynamic interaction of two drugs on the scaffold of Ca channels.
Topics: Sofosbuvir; Amiodarone; Antiviral Agents; Myocytes, Cardiac; Binding Sites; Calcium Channels, L-Type; Calcium
PubMed: 36417914
DOI: 10.1016/j.cell.2022.10.024 -
Journal of the American College of... Apr 2022In patients with ischemic cardiomyopathy and an implantable cardioverter-defibrillator (ICD), catheter ablation and antiarrhythmic drugs (AADs) reduce ICD shocks, but... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
In patients with ischemic cardiomyopathy and an implantable cardioverter-defibrillator (ICD), catheter ablation and antiarrhythmic drugs (AADs) reduce ICD shocks, but the most effective approach remains uncertain.
OBJECTIVES
This trial compares the efficacy and safety of catheter ablation vs AAD as first-line therapy in ICD patients with symptomatic ventricular tachycardias (VTs).
METHODS
The SURVIVE-VT (Substrate Ablation vs Antiarrhythmic Drug Therapy for Symptomatic Ventricular Tachycardia) is a prospective, multicenter, randomized trial including patients with ischemic cardiomyopathy and appropriated ICD shock. Patients were 1:1 randomized to complete endocardial substrate-based catheter ablation or antiarrhythmic therapy (amiodarone + beta-blockers, amiodarone alone, or sotalol ± beta-blockers). The primary outcome was a composite of cardiovascular death, appropriate ICD shock, unplanned hospitalization for worsening heart failure, or severe treatment-related complications.
RESULTS
In this trial, 144 patients (median age, 70 years; 96% male) were randomized to catheter ablation (71 patients) or AAD (73 patients). After 24 months, the primary outcome occurred in 28.2% of patients in the ablation group and 46.6% of those in the AAD group (hazard ratio [HR]: 0.52; 95% CI: 0.30-0.90; P = 0.021). This difference was driven by a significant reduction in severe treatment-related complications (9.9% vs 28.8%, HR: 0.30; 95% CI: 0.13-0.71; P = 0.006). Eight patients were hospitalized for heart failure in the ablation group and 13 in the AAD group (HR: 0.56; 95% CI: 0.23-1.35; P = 0.198). There was no difference in cardiac mortality (HR: 0.93; 95% CI: 0.19-4.61; P = 0.929).
CONCLUSIONS
In ICD patients with ischemic cardiomyopathy and symptomatic VT, catheter ablation reduced the composite endpoint of cardiovascular death, appropriate ICD shock, hospitalization due to heart failure, or severe treatment-related complications compared to AAD. (Substrate Ablation vs Antiarrhythmic Drug Therapy for Symptomatic Ventricular Tachycardia [SURVIVE-VT]: NCT03734562).
Topics: Aged; Amiodarone; Anti-Arrhythmia Agents; Cardiomyopathies; Catheter Ablation; Defibrillators, Implantable; Female; Heart Failure; Humans; Male; Myocardial Ischemia; Prospective Studies; Tachycardia, Ventricular; Treatment Outcome
PubMed: 35422240
DOI: 10.1016/j.jacc.2022.01.050