Antidotes for acute cardenolide (cardiac glycoside) poisoning

2023 American Heart Association Focused Update on the Management of Patients With Cardiac Arrest or Life-Threatening Toxicity Due to Poisoning: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

In this focused update, the American Heart Association provides updated guidance for resuscitation of patients with cardiac arrest, respiratory arrest, and refractory shock due to poisoning. Based on structured evidence reviews, guidelines are provided for the treatment of critical poisoning from benzodiazepines, β-adrenergic receptor antagonists (also known as β-blockers), L-type calcium channel antagonists (commonly called calcium channel blockers), cocaine, cyanide, digoxin and related cardiac glycosides, local anesthetics, methemoglobinemia, opioids, organophosphates and carbamates, sodium channel antagonists (also called sodium channel blockers), and sympathomimetics. Recommendations are also provided for the use of venoarterial extracorporeal membrane oxygenation. These guidelines discuss the role of atropine, benzodiazepines, calcium, digoxin-specific immune antibody fragments, electrical pacing, flumazenil, glucagon, hemodialysis, hydroxocobalamin, hyperbaric oxygen, insulin, intravenous lipid emulsion, lidocaine, methylene blue, naloxone, pralidoxime, sodium bicarbonate, sodium nitrite, sodium thiosulfate, vasodilators, and vasopressors for the management of specific critical poisonings.

A study of socio clinical, biochemical and electrocardiographic changes of yellow oleander seed poisoning in India

Yellow oleander (Thevetia peruviana), which belongs to the Apocyanaceae family, is a common shrub seen throughout the tropics. All parts of the plant contain high concentrations of cardiac glycosides, which are toxic to cardiac muscle and the autonomic nervous system. The main objective of this study was to socio-clinical, biochemical and electrocardiographic changes of yellow oleander seed poisoning. This prospective observational study was conducted over a period of 6 months (March 2022 to September 2022). Oleander seed poison in most prevalent in the 21-40 years age. More the crushed seeds consumed and the delay to admission to the hospital for treatment poorer was the outcome. The most common GI symptoms of yellow oleander poisoning were vomiting (58 %), abdominal pain (28%), diarrhoea (9%), and palpitations (20%), dizziness (18%).Serum potassium levels that were measured during the admission were directly related to the ECG changes. ECG changes were more observed with patients those who consumed seeds in crushed form and this difference is statistically significant (P = 0.0001). Higher incidence of cardiotoxicity was noted with patients those who consumed poison on empty stomach compare to who consumed after food. The Electrocardiographic manifestations was found even with consumption of one seed, number of seeds consumptions independent of cardiotoxicity.Additonally higher mean Potassium value observed in patients who had cardiotoxicity when compared to patient who had no cardiotoxicity. Death of the patients in yellow oleander seed poisoning was independent of quantity of the seeds they have ingested.

Foxglove poisoning: diagnostic and therapeutic differences with medicinal digitalis glycosides overdose

We report a case of a 19-year-old woman who ingested Digitalis purpurea leaves as a suicide attempt. She developed gastro-intestinal symptoms, loss of colour vision, cardiac conduction disturbances as well as an elevated serum potassium. Treatment was initiated in analogy to medicinal digoxin poisoning by means of digoxin-specific Fab-fragments with a good effect. However during the further course we faced difficulties of prolonged intestinal absorption and inability to estimate the ingested dose or half-life of the vegetal cardiac glycoside compounds. To prevent further absorption and interrupt enterohepatic recycling, multi-dose activated charcoal was administered. Because of a relapse of cardiac conduction disturbances and hyperkalemia, two supplementary doses of Fab-fragments were given, up to a total dose of nineteen vials (one vial containing 40 mg). The important diagnostic and therapeutic differences of vegetal digitalis intoxication as compared to medicinal intoxication and the applicability of existing guidelines on medicinal digitalis intoxication in the light of these differences will be discussed here.

A Novel Cardenolide Glycoside Isolated from Xysmalobium undulatum Reduces Levels of the Alzheimer's Disease-Associated β-Amyloid Peptides Aβ42 In Vitro

Elevated levels of the amylo β-proteins (Aβ), particularly Aβ42, are associated with a high risk of Alzheimer’s disease (AD). The Aβ proteins are produced from cellular processing of the amyloid precursor proteins (APPs). To identify natural products that block the formation of Aβ-proteins from APPs, we previously screened a library of plant extracts and identified Xysmalobium undulaum (Apocynaceae) as a potential plant for further research. Here, we provide a report on the isolation and identification of the active principles from the plant species using a bioassay-guided fractionation. Fractions and resulting pure compounds from the purification process of the extract of X. undulatum were screened in vitro against APPs transfected HeLa cell lines. Three compounds, acetylated glycosydated crotoxogenin (1), xysmalogenin-3, β-d-glucopyranoside (2), and crotoxigenin 3-O-glucopyranoside (3), were subsequently isolated and their structures elucidated using NMR and mass spectrometry. Compound 1, a novel cardenolide, and 2 significantly decreased the Aβ42 levels in a dose-dependent manner while compound 3 was inactive. In silico investigations identified the AD’s β-secretase enzyme, BACE1, as a potential target for these compounds with the glycoside moiety being of significance in binding to the enzyme active site. Our study provides the first report of a novel cardenolide and the potential of cardenolides as chemical scaffolds for developing AD treatment drugs.

Clinical Use of Digitalis: A State of the Art Review

The history of digitalis is rich and interesting, with the first use usually attributed to William Withering and his study on the foxglove published in 1785. However, some knowledge of plants with digitalis-like effects used for congestive heart failure (CHF) was in evidence as early as Roman times. The active components of the foxglove (Digitalis purpurea and Digitalis lanata) are classified as cardiac glycosides or cardiotonic steroids and include the well-known digitalis leaf, digitoxin, and digoxin; ouabain is a rapid-acting glycoside usually obtained from Strophanthus gratus. These drugs are potent inhibitors of cellular membrane sodium-potassium adenosine triphosphatase (Na⁺/K⁺-ATPase). For most of the twentieth century, digitalis and its derivatives, especially digoxin, were the available standard of care for CHF. However, as the century closed, many doubts, especially regarding safety, were raised about their use as other treatments for CHF, such as decreasing the preload of the left ventricle, were developed. Careful attention is needed to maintain the serum digoxin level at ≤ 1.0 ng/ml because of the very narrow therapeutic window of the medication. Evidence for benefit exists for CHF with reduced ejection fraction (EF), also referred to as heart failure with reduced EF (HFrEF), especially when considering the combination of mortality, morbidity, and decreased hospitalizations. However, the major support for using digoxin is in atrial fibrillation (AF) with a rapid ventricular response when a rate control approach is planned. The strongest support of all for digoxin is for its use in rate control in AF in the presence of a marginal blood pressure, since all other rate control medications contribute to additional hypotension. In summary, these days, digoxin appears to be of most use in HFrEF and in AF with rapid ventricular response for rate control, especially when associated with hypotension. The valuable history of the foxglove continues; it has been modified but not relegated to the garden or the medical history book, as some would advocate.

Fatality Following Intentional Ingestion of Cerbera odollam Seeds

Seeds from the mangrove plant Cerbera (C.) odollam, known as the “suicide tree,” are responsible for a significant number of plant deaths worldwide but are not well recognized in Western medicine. Cerberin is a cardiac glycoside concentrated in the plant’s seeds, which causes disrupted cardiac electrical activity leading to fatal dysrhythmias. We present a fatal case of intentional C. odollam seed ingestion. The patient experienced high-degree heart block and cardiac arrest despite supportive treatment and digoxin immune fab administration. Clinicians should be aware of the potential morbidity and mortality associated with C. odollam poisoning and be prepared for resuscitative interventions.

Retrospective evaluation of patients with elevated digoxin levels at an emergency department

Objectives

We investigated the demographic characteristics, clinical and laboratory findings, treatment strategies and clinical outcomes of patients presenting at emergency department (ED) with digoxin levels at or above 1.2 ng/ml.

Materials and methods

The demographic and clinical characteristics of patients with serum digoxin levels at or above 1.2 ng/ml admitted to an ED between January 2010 and July 2011 were investigated in this cross-sectional descriptive study. Patients with ECG and clinical findings consistent with digoxin toxicity and no additional explanation of their symptoms were evaluated for digoxin toxicity.

Results

In this study 137 patients were included, and 68.6% of patients were women with mean age 76.1 ± 12.2. There was no significant difference between gender and digoxin intoxication. The mean age of intoxicated group was significantly higher than the non-intoxicated group (P = 0.03). The most common comorbidities were congestive heart failure (n = 91) and atrial fibrillation (n = 74). The most common symptoms were nausea, vomiting and abdominal pain. The levels of hospitalization and mortality in this group were significantly higher.

Conclusion

Digoxin intoxication must be suspected in patients present in the ED, particularly those with complaints that include nausea and vomiting, as well as new ECG changes; serum digoxin levels must be determined.

Pharmacological treatment of cardiac glycoside poisoning

Cardiac glycosides are an important cause of poisoning, reflecting their widespread clinical usage and presence in natural sources. Poisoning can manifest as varying degrees of toxicity. Predominant clinical features include gastrointestinal signs, bradycardia and heart block. Death occurs from ventricular fibrillation or tachycardia. A wide range of treatments have been used, the more common including activated charcoal, atropine, β-adrenoceptor agonists, temporary pacing, anti-digoxin Fab and magnesium, and more novel agents include fructose-1,6-diphosphate (clinical trial in progress) and anticalin. However, even in the case of those treatments that have been in use for decades, there is debate regarding their efficacy, the indications and dosage that optimizes outcomes. This contributes to variability in use across the world. Another factor influencing usage is access. Barriers to access include the requirement for transfer to a specialized centre (for example, to receive temporary pacing) or financial resources (for example, anti-digoxin Fab in resource poor countries). Recent data suggest that existing methods for calculating the dose of anti-digoxin Fab in digoxin poisoning overstate the dose required, and that its efficacy may be minimal in patients with chronic digoxin poisoning. Cheaper and effective medicines are required, in particular for the treatment of yellow oleander poisoning which is problematic in resource poor countries.