Digoxin: its role in contemporary medicine

Safety and Effectiveness of Antidysrhythmic Drugs for Pharmacologic Cardioversion of Recent-Onset Atrial Fibrillation: a Systematic Review and Bayesian Network Meta-analysis

PURPOSE

The available evidence to determine which antidysrhythmic drug is superior for pharmacologic cardioversion of recent-onset (onset within 48 h) atrial fibrillation (AF) is uncertain. We aimed to identify the safest and most effective agent for pharmacologic cardioversion of recent-onset AF in the emergency department.

METHODS

We searched MEDLINE, Embase, and Web of Science from inception to February 21, 2023 (PROSPERO: CRD42018083781). Eligible studies were randomized controlled trials that enrolled adult participants with AF ≤ 48 h, compared a guideline-recommended antidysrhythmic drug with another antidysrhythmic drug or a different formulation of the same drug or placebo and reported specific adverse events. The primary outcome was immediate, serious adverse event - cardiac arrest, sustained ventricular tachydysrhythmia, atrial flutter 1:1 atrioventricular conduction, hypotension, and bradycardia. Additional analyses included the outcomes of conversion to sinus rhythm within 4 h and 24 h. We extracted data according to PRISMA-NMA and appraised trials using Cochrane RoB 2. We performed Bayesian network meta-analysis (NMA) using a Markov Chain Monte Carlo method with random-effect model and vague prior distribution to calculate odds ratios with 95% credible intervals. We assessed confidence using CINeMA. We used surface under the cumulative ranking curve (SUCRA) to rank agent(s).

RESULTS

The systematic review initially identified 5545 studies. Twenty-five studies met eligibility criteria, and 22 studies (n = 3082) provided data for NMA, which demonstrated that vernakalant (SUCRA = 70.9%) is most likely to be safest. Additional effectiveness NMA demonstrated that flecainide (SUCRA = 89.0%) is most likely to be superior for conversion within 4 h (27 studies; n = 2681), and ranolazine-amiodarone IV (SUCRA 93.7%) is most likely to be superior for conversion within 24 h (24 studies; n = 3213). Confidence in the NMA estimates is variable and limited mostly by within-study bias and imprecision.

CONCLUSIONS

Among guideline-recommended antidysrhythmic drugs, the combination of digoxin IV and amiodarone IV is definitely among the least safe for cardioversion of recent onset AF; flecainide, vernakalant, ibutilide, propafenone, and amiodarone IV are definitely among the most effective for cardioversion within 4 h; flecainide is definitely among the most effective for cardioversion within 24 h. Further, randomized controlled trials with predetermined and strictly defined, hemodynamic adverse event outcomes are recommended.

Fe(III)-catalyzed stereoselective synthesis of deoxyglycosides using stable bifunctional deoxy-phenylpropiolate glycoside donors

Herein, we report a mild and economical route for the stereoselective synthesis of 2-deoxy and 2,6-dideoxyglycosides via FeCl3-catalyzed activation of bench stable deoxy-phenylpropiolate glycosyl donors (D-PPGs). Optimized reaction conditions work well under additive-free conditions to afford the corresponding 2-deoxy and 2,6-dideoxyglycosides in good yields with high α-anomeric selectivity by reacting with sugar and non-sugar-based acceptors. The optimized conditions were also extended for disarmed D-PPG donors. In addition, the developed strategy is amenable to high-scale-up synthesis.

Reagent-controlled chemo/stereoselective glycosylation of ʟ-fucal to access rare deoxysugars

2,6-Dideoxy sugars constitute an important class of anticancer antibiotics natural products and serve as essential medicinal tools for carbohydrate-based drug discovery and vaccine development. In particular, 2-deoxy ʟ-fucose or ʟ-oliose is a rare sugar and vital structural motif of several potent antifungal and immunosuppressive bioactive molecules. Herein, we devised a reagent-controlled stereo and chemoselective activation of ʟ-fucal, enabling the distinctive glycosylation pathways to access the rare ʟ-oliose and 2,3-unsaturated ʟ-fucoside. The milder oxo-philic Bi(OTf)3 catalyst induced the direct 1,2-addition predominantly, whereas B(C6F5)3 promoted the allylic Ferrier-rearrangement of the enol-ether moiety in ʟ-fucal glycal donor, distinguishing the competitive mechanisms. The reagent-tunable modular approach is highly advantageous, employing greener catalysts and atom-economical transformations, expensive ligand/additive-free, and probed for a diverse range of substrates comprising monosaccharides, amino-acids, bioactive natural products, and drug scaffolds embedded with susceptible or labile functionalities.

Discovery of effective combination from Renshen-Fuzi herbal pair against heart failure by spectrum-effect relationship analysis and zebrafish models

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional herbal pair Ginseng Radix et Rhizoma (roots and rhizomes of Panax ginseng C.A. Mey, Renshen in Chinese) and Aconiti Lateralis Radix Praeparata (lateral roots of Aconitum carmichaelii Debeaux, Fuzi in Chinese), composition of two traditional Chinese medicinal herbs, has been widely used in traditional Chinese medicine formula, in which Shenfu decoction has been used clinically in China for the treatment of heart failure at present.

AIM OF THE STUDY

Although the ginsenosides and aconite alkaloids have been proven as the essential bioactive components in Renshen-Fuzi herbal pair, the exact composition of effective components to combat heart failure are still unclear. Therefore, spectrum-effect relationship analysis was performed to reveal its effective combination for anti-heart failure effect.

MATERIALS AND METHODS

Firstly, the chemical constituents of Renshen-Fuzi herbal pair were identified using ultra high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). The 39 major compounds in Renshen-Fuzi with five different compatibility ratios were simultaneously quantified using ultra high-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UHPLC-QQQ MS/MS). Subsequently, zebrafish models induced by verapamil hydrochloride were constructed and four heart failure-related indexes were selected for pharmacodynamic evaluation of Renshen-Fuzi. To analyze the spectrum-effect relationships, partial least squares regression (PLSR) models were established among the contents of 39 compounds in Renshen-Fuzi with each pharmacodynamic index. According to the contribution of each compound to the whole efficacy, 12 compounds were finally screened out as the effective combination.

RESULTS

A total of 157 chemical compounds of Renshen-Fuzi herbal pair were identified, in which 39 components were simultaneously determined. The pharmacological effects indicated that Renshen-Fuzi with 1:2 ratio exhibited the best effect based on zebrafish model, which could improve cardiac output and blood flow velocity and inhibit pericardial enlargement and venous blood stasis significantly. A combination of 9 ginsenosides and 3 aconite alkaloids based on a component-efficacy modeling by PLSR was screened, and exerted approximately equivalent pharmacological effects compared with Renshen-Fuzi herbal pair.

CONCLUSIONS

Our findings elucidated the effective combination of Renshen-Fuzi herbal pair that has been used in clinic for the treatment of heart failure, which could also promote the pharmacological research and quality control of their formula such as Shenfu decoction.

Stereoselective Synthesis of 2-Deoxy Glycosides via Iron Catalysis

An Fe-catalyzed 2-deoxy glycosylation method was developed from 3,4-O-carbonate glycals directly at room temperature. This novel approach enabled facile access to alkyl and aryl 2-deoxy glycosides in high yields with exclusive α-stereoselectivity, tolerating various alcohols, phenols, and glycals. The synthetic utility and advantage of this strategy have been demonstrated by the modification of six natural products and the construction of a tetrasaccharide.

Effects of Corchorusoside C on NF-κB and PARP-1 Molecular Targets and Toxicity Profile in Zebrafish

The present study aims to continue the study of corchorusoside C (1), a cardenolide isolated from Streptocaulon juventas, as a potential anticancer agent. A mechanistic study was pursued in a zebrafish model and in DU-145 prostate cancer cells to investigate the selectivity of 1 towards NF-κB and PARP-1 pathway elements. Compound 1 was found to inhibit the expression of IKKα and NF-κB p65 in TNF-α induced zebrafish and inhibit the expression of NIK in vitro. The protein expression levels of XRCC-1 were increased and p53 decreased in DU-145 cells. XIAP protein expression was initially decreased after treatment with 1, followed by an increase in expression at doses higher than the IC₅₀ value. The activity of caspase-1 and the protein expression levels of IL-18 were both decreased following treatment of 1. The binding interactions for 1 to NIK, XRCC-1, p53, XIAP, and caspase-1 proteins were explored in molecular docking studies. Additionally, the toxicity profile of 1 in zebrafish was favorable in comparison to its analog digoxin and other anticancer drugs at the same MTD in zebrafish. Overall, 1 targets the noncanconical NF-κB pathway in vivo and in vitro, and is well tolerated in zebrafish supporting its potential in the treatment of prostate cancer.

Cardiac steroid ouabain transcriptionally increases human leukocyte antigen DR expression on monocytes

Sepsis is a life-threatening disease characterized by acute multiple organ dysfunction and immunosuppression that is also called as immunoparalysis. Increasing evidence suggests that immunoparalysis largely contributes to the high mortality of sepsis, but the effective remedies are lacking. As an important antigen presentation molecule, human leukocyte antigen DR (HLA-DR) is remarkably down-regulated in sepsis-induced immunoparalysis, therefore, re-stimulation of HLA-DR expression is expected to be useful in reversing immunoparalysis. We previously described that ouabain, as a Na⁺, K⁺-ATPase ligand, is able to counteract immunoparalysis by regulating TH1 cytokines expression. Here, we expanded the finding that ouabain not only prevents LPS-induced down-regulation of HLA-DR on monocytes, but also transcriptionally activates HLA-DR α/β expression mediated by CIITA4, IRF1, c-Src, and Stat1 phosphorylation. Since ouabain can improve sepsis-induced immunoparalysis by multiple mechanisms, we propose that ouabain may be a promising agent in septic therapy that deserves further investigation.

Evaluation of Cardiotonic Steroid Modulation of Cellular Cholesterol and Phospholipid

We have previously shown that 21-benzylidene digoxin (21-BD) increases the total cholesterol and phospholipid content on the membrane of HeLa cells. Lipid modulation caused by cardiotonic steroids (CTS) is still unexplored. Therefore, the aim of the present study was to evaluate the cholesterol and phospholipid modulation of the cell membrane caused by ouabain and 21-BD and the possible involvement of the caveolae on this modulation. For this, one cell line containing caveolae (HeLa) and other not containing (Caco-2) were used. The modulation of the lipid profile was evaluated by total cholesterol and phospholipids measurements, and identification of membrane phospholipids by HPTLC. The cholesterol distribution was evaluated by filipin staining. The caveolin-1 expression was evaluated by Western Blotting. Ouabain had no effect on the total membrane lipid content in both cell lines. However, 21-BD increased total membrane phospholipid content and had no effect on the membrane cholesterol content in Caco-2 cells. CTS were not able to alter the specific phospholipids content. In the filipin experiments, 21-BD provoked a remarkable redistribution of cholesterol to the perinuclear region of HeLa cells. In Caco-2 cells, it was observed only a slight increase in cholesterol, especially as intracellular vesicles. The caveolin-1 expression was not altered by any of the compounds. Our data mainly show different effects of two cardiotonic steroids. Ouabain had no effect on the lipid profile of cells, whereas 21-BD causes important changes in cholesterol and phospholipid content. Therefore, the modulation of cholesterol content in the plasma membrane of HeLa cells is not correlated with the expression of caveolin-1.

Periplocymarin Plays an Efficacious Cardiotonic Role via Promoting Calcium Influx

Periplocymarin, which belongs to cardiac glycosides, is an effective component extracted from Periplocae Cortex. However, its cardiovascular effects remain unidentified. In the present study, injection of periplocymarin (5 mg/kg) through external jugular vein immediately increased the mean arterial pressure (MAP) in anesthetized C57BL/6 mice. Ex vivo experiments using mouse mesenteric artery rings were conducted to validate the role of periplocymarin on blood vessels. However, periplocymarin failed to induce vasoconstriction directly, and had no effects on vasoconstriction induced by phenylephrine (Phe) and angiotensin II (Ang II). In addition, vasodilatation induced by acetylcholine (Ach) was insusceptible to periplocymarin. Echocardiography was used to evaluate the effects of periplocymarin on cardiac function. The results showed that the injection of periplocymarin significantly increase the ejection fraction (EF) in mice without changing the heart rate. In vitro studies using isolated neonatal rat ventricular myocytes (NRVMs) revealed that periplocymarin transiently increased the intracellular Ca²⁺ concentration observed by confocal microscope. But in Ca²⁺-free buffer, this phenomenon vanished. Besides, inhibition of sodium potassium-activated adenosine triphosphatase (Na⁺-K⁺-ATPase) by digoxin significantly suppressed the increase of MAP and EF in mice, and the influx of Ca²⁺ in cardiomyocytes, mediated by periplocymarin. Collectively, these findings demonstrated that periplocymarin increased the contractility of myocardium by promoting the Ca²⁺ influx of cardiomyocytes via targeting on Na⁺-K⁺-ATPase, which indirectly led to the instantaneous rise of blood pressure.

Effect of green tea catechins on the pharmacokinetics of digoxin in humans

Background

Previous in vitro studies have reported the inhibitory effect of green tea on p-glycoprotein (p-gp) encoded by ABCB1. This study aimed to investigate the effect of green tea on the pharmacokinetics of digoxin, a typical probe drug of p-gp.

Methods

Sixteen healthy volunteers participated in this study. At Day 1, 0.5 mg of digoxin was administered via oral route. After a 14-day washout period, 630 mg of green tea catechins (GTC) was administered via oral route, followed by 0.5 mg of digoxin 1 hour later. From Day 16 through Day 28, 630 mg of GTC was administered alone. At Day 29, 630 mg of GTC and 0.5 mg of digoxin were administered in the same way as Day 15. Blood samples for the pharmacokinetic assessments of digoxin were collected up to 8 hours after each dose. Pharmacokinetic parameters were estimated by noncompartmental analysis. Area under the curve (AUC) and peak plasma concentration (C_max) were compared using mixed effect model between digoxin alone and digoxin with GTC. ABCB1 was genotyped to determine whether its polymorphism affects digoxin–GTC interaction.

Results

Fifteen subjects completed the study. Compared to digoxin alone, the concomitant administration of digoxin and GTC significantly reduced the systemic exposure of digoxin: geometric mean ratios (GMR) and 90% confidence intervals (CI) of area under the concentration–time curve from time 0 to the last measurable time (AUC_last) and C_max were 0.69 (0.62–0.75) and 0.72 (0.61–0.85), respectively. The concomitant administration of digoxin and GTC following pretreatment of GTC (Day 29) similarly reduced the AUC_last (GMR [90% CI]: 0.67 [0.61–0.74]) and C_max (GMR [90% CI]: 0.74 [0.63–0.87]). In the comparison of the percentage changes from Day 1 (digoxin single administration) of AUC_last between genotypes, C1236T variant type showed a significant difference to wild-type on Day 15 (concomitant administration of digoxin and GTC) (P=0.005).

Conclusion

This study demonstrates that the coadministration of GTC reduces the systemic exposure of digoxin regardless of pretreatment of GTC.

Comprehensive review of cardiovascular toxicity of drugs and related agents

Cardiovascular diseases are a leading cause of morbidity and mortality in most developed countries of the world. Pharmaceuticals, illicit drugs, and toxins can significantly contribute to the overall cardiovascular burden and thus deserve attention. The present article is a systematic overview of drugs that may induce distinct cardiovascular toxicity. The compounds are classified into agents that have significant effects on the heart, blood vessels, or both. The mechanism(s) of toxic action are discussed and treatment modalities are briefly mentioned in relevant cases. Due to the large number of clinically relevant compounds discussed, this article could be of interest to a broad audience including pharmacologists and toxicologists, pharmacists, physicians, and medicinal chemists. Particular emphasis is given to clinically relevant topics including the cardiovascular toxicity of illicit sympathomimetic drugs (e.g., cocaine, amphetamines, cathinones), drugs that prolong the QT interval, antidysrhythmic drugs, digoxin and other cardioactive steroids, beta-blockers, calcium channel blockers, female hormones, nonsteroidal anti-inflammatory, and anticancer compounds encompassing anthracyclines and novel targeted therapy interfering with the HER2 or the vascular endothelial growth factor pathway.

Increased All-Cause Mortality Associated With Digoxin Therapy in Patients With Atrial Fibrillation: An Updated Meta-Analysis

Digoxin is still commonly used in atrial fibrillation (AF) patients with and without heart failure (HF) for heart rate control. Studies concerning the detrimental effects of digoxin therapy in AF patients are inconsistent. This updated meta-analysis examined the association of digoxin therapy with all-cause mortality in AF patients, stratified by heart function status. We included observational studies with multivariate-adjusted data on digoxin and all-cause mortality in the analysis. The relative risks (RRs) of all-cause mortality were calculated and reported with 95% confidence intervals (95% CIs). Seventeen studies comprising 408,660 patients were included. Overall, in AF patients, digoxin treatment was associated with a significant increase in all-cause mortality after multivariate-adjustment (RR = 1.22; 95% CI 1.15-1.30). When stratified by heart function status, digoxin treatment was associated with a 14% increase in all-cause mortality in AF patients with HF (RR = 1.14, 95% CI 1.04-1.24), and a 36% increase in those without HF (RR = 1.36, 95% CI 1.18-1.56). The increased risk of all-cause mortality was significantly higher in AF patients without HF compared with those with HF (P for interaction = 0.04). This meta-analysis demonstrates that digoxin therapy was associated with a significant increase in all-cause mortality in AF patients, especially in those without HF. Given other available options, digoxin should be avoided as a first-line agent for heart rate control in AF patients.

Digoxin: A systematic review in atrial fibrillation, congestive heart failure and post myocardial infarction

AIM

To review digoxin use in systolic congestive heart failure, atrial fibrillation, and after myocardial infarction.

METHODS

A comprehensive PubMed search was performed using the key words "digoxin and congestive heart failure", "digoxin and atrial fibrillation", "digoxin, atrial fibrillation and systolic congestive heart failure", and "digoxin and myocardial infarction". Only articles written in English were included in this study. We retained studies originating from randomized controlled trials, registries and included at least 500 patients. The studies included patients with atrial fibrillation or heart failure or myocardial infarction and had a significant proportion of patients (at least 5%) on digoxin. A table reviewing the different hazard ratios was developed based on the articles selected. Our primary endpoint was the overall mortality in the patients on digoxin vs those without digoxin, among patients with atrial fibrillation and also among patients with atrial fibrillation and systolic heart failure. We reviewed the most recent international guidelines to discuss current recommendations.

RESULTS

A total of 18 studies were found that evaluated digoxin and overall mortality in different clinical settings including systolic congestive heart failure and normal sinus rhythm (n = 5), atrial fibrillation with and without systolic congestive heart failure (n = 9), and myocardial infarction (n = 4). Overall, patients with systolic congestive heart failure with normal sinus rhythm, digoxin appears to have a neutral effect on mortality especially if close digoxin level monitoring is employed. However, most of the observational studies evaluating digoxin use in atrial fibrillation without systolic congestive heart failure showed an increase in overall mortality when taking digoxin. In the studies evaluated in this systematic review, the data among patients with atrial fibrillation and systolic congestive heart failure, as well as post myocardial infarction were more controversial. The extent to which discrepancies among studies are based on statistical methods is currently unclear, as these studies' findings are generated by retrospective analyses that employed different techniques to address confounding.

CONCLUSION

Based on the potential risks and benefits, as well as the presence of alternative drugs, there is a limited role for digoxin in the management of patients with normal sinus rhythm and congestive heart failure. Based on the retrospective studies reviewed there is a growing volume of data showing increased mortality in those with only atrial fibrillation. The proper role of digoxin is, however, less certain in other subgroups of patients, such as those with both atrial fibrillation and systolic congestive heart failure or after a myocardial infarction. Further studies may provide helpful information for such subgroups of patients.