Clinical Utility of Serum Digoxin Level in Cardiac Patients for Diagnosis of Chronic Digitalis Toxicity

Ahmed Refat Ragab

doi:10.4172/2161-0495.1000150

Abstract

Digitalis toxicity is a complication of the digitalis therapy. It could occur also due to the patient taking in a much larger dose of the drug than prescribed. The general symptoms of Digitalis toxicity are typically gastro-intestinal, neurologic and non-specific cardiac type manifestations that are strikingly similar to the clinical picture of primary Congestive Heart Failure (CHF) making a diagnosis of chronic digitalis toxicity in particular relatively difficult. Serum digoxin measurement is today becoming a crucial subject of concern because of the narrow therapeutic window of digoxin besides increasing mortality and morbidity due to its intoxication. The present work is focused on evaluating the clinical value of Serum Digoxin Concentrations (SDCs) in relation to appropriate assessment of chronic digitalis toxicity in cardiac patients. The current study was conducted in the form of a cross-sectional Electronic Medical Record (EMR) review study of patients presently on continuous prescriptions for digoxin with there being zero gaps in therapy for at least 10 days prior to SDC result entered into the Online Analytical Toxicology Request Result (OTARR). There was also a complete clinical examination report as well as a review of the results of serum potassium concentration, liver and kidney functions. Patients with digoxin toxicity (11.9%) had a significantly higher mean SDC (2.75 ± 1.2) than those with subtherapeutic (0.67 ± 0.17 ng/mL) or eutherapeutic SDC (1.19 ± 0.26 ng/mL) (p value ≤ 0.05). About 12% of the total cases showed an abnormal serum potassium concentration of electrolyte fluctuations. From this, one can conclude that a regular monitoring of serum digoxin level would be seen as mandatory for the verification of digoxin’s therapeutic effects and then the subsequent prevention and early diagnosis of chronic toxicity.

Highlights

Digoxin, a purified cardiac glycoside, is widely prescribed as medications despite there being several adverse drug reactions due to it [1]
Adult patients monitored for Serum Digoxin Concentrations (SDCs) in two hospitals (Dammam Medical Complex and Qatif Central Hospital) that were participating
Atrial fibrillation and heart failure were the commonest conditions (69.6%) consistent with indications of digoxin therapy in this study whereas sole diagnosis as heart failure was found in 23.5% of our case series

Summary

Introduction

A purified cardiac glycoside, is widely prescribed as medications despite there being several adverse drug reactions due to it [1]. Digitalis preparations have been used therapeutically for over two centuries, it is still quite difficult to diagnose digoxin toxicity. The various symptomatic indications with regard to toxicity are still non-specific, in the same way as are electrocardiographic changes. At a specific given Serum Digoxin Concentration (SDC) ‘Therapeutic’ and ‘toxic’ concentrations do overlap. A patient may be able to control ventricular response without any adverse effects, while another may exhibit toxicity. Therapeutic drug monitoring steps up the patient care and are very likely a contributing factor to the suspected decrease in digoxin toxicity; Yet, elevated concentrations are not the only reasons for toxicity [2]

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Discussion

Conclusion