Digoxin remains a cornerstone in the management of certain cardiac conditions, offering a time-tested approach to optimizing heart performance. As a cardiac glycoside derived from the Digitalis lanata plant, it exerts positive inotropic and negative chronotropic effects, making it invaluable for specific patient populations. This product card provides a comprehensive, expert-level overview of its pharmacological profile, clinical application, and essential safety information for healthcare professionals.

Features

• Contains digoxin as the active pharmaceutical ingredient
• Available in oral tablet (e.g., 0.125 mg, 0.25 mg) and intravenous formulations
• Exhibits a narrow therapeutic index requiring careful monitoring
• Demonstrates both positive inotropic and negative chronotropic properties
• Characterized by a long half-life (approximately 36-48 hours in patients with normal renal function)
• Undergoes primarily renal elimination

Benefits

• Enhances myocardial contractility, improving cardiac output in patients with systolic heart failure
• Provides controlled reduction of ventricular rate in atrial fibrillation and atrial flutter
• May reduce hospitalization rates in heart failure patients when used appropriately
• Offers flexible administration routes (oral and intravenous) for various clinical scenarios
• Enables long-term management with once-daily dosing in most patients
• Provides a cost-effective treatment option compared to some newer cardiovascular agents

Common use

Digoxin is primarily indicated for the treatment of mild to moderate heart failure in patients who remain symptomatic despite appropriate management with ACE inhibitors, diuretics, and beta-blockers. It is also approved for the control of ventricular response rate in patients with chronic atrial fibrillation. The medication may be considered as adjunctive therapy when standard treatments provide insufficient symptomatic relief or when rate control proves challenging with other agents. Its use requires careful patient selection and ongoing monitoring due to its narrow therapeutic window.

Dosage and direction

Dosing must be individualized based on patient factors including age, weight, renal function, and concomitant medications. For most adults with normal renal function, the typical maintenance dose ranges from 0.125 mg to 0.25 mg daily. Loading doses may be used in urgent situations but require careful calculation and monitoring. Administration should occur at approximately the same time each day. For intravenous administration, the dose is typically 80-85% of the oral dose. Regular assessment of serum digoxin levels is essential, with the therapeutic range generally considered to be 0.5-2.0 ng/mL, though clinical response should guide therapy rather than levels alone.

Precautions

Regular monitoring of renal function, electrolytes (particularly potassium, magnesium, and calcium), and digoxin levels is mandatory. Hypokalemia, hypomagnesemia, and hypercalcemia may predispose patients to toxicity. Use with caution in elderly patients and those with renal impairment, as reduced clearance may lead to accumulation. Thyroid disorders may alter digoxin requirements. Patients should be educated to recognize early signs of toxicity and report them immediately. Electrocardiographic monitoring is recommended during initiation and dosage adjustments.

Contraindications

Digoxin is contraindicated in patients with ventricular fibrillation, known hypersensitivity to digoxin or other digitalis preparations, and in cases of digoxin toxicity. Additional contraindications include certain types of supraventricular arrhythmias that may be exacerbated by AV node blockade, such as Wolff-Parkinson-White syndrome with atrial fibrillation. It should not be used in patients with amyloid cardiomyopathy or constrictive pericarditis unless the benefits clearly outweigh the risks.

Possible side effect

Common adverse effects include nausea, vomiting, diarrhea, headache, dizziness, and visual disturbances (particularly yellow-green halos around objects). Cardiac effects may include various arrhythmias, with premature ventricular contractions being most common. Serious side effects can include complete heart block, ventricular tachycardia, and atrial tachycardia with block. Neuropsychiatric effects such as fatigue, weakness, and rarely, psychosis may occur. Gynecomastia has been reported with long-term use in some male patients.

Drug interaction

Numerous significant interactions exist. Diuretics may cause hypokalemia, increasing toxicity risk. Calcium channel blockers (particularly verapamil), amiodarone, quinidine, and propafenone can increase digoxin levels. Concomitant use with beta-blockers or calcium channel blockers may excessively slow heart rate. Antibiotics such as erythromycin and tetracycline may increase bioavailability. Antacids, cholestyramine, and certain antineoplastic agents may decrease absorption. Sympathomimetics may increase the risk of arrhythmias.

Missed dose

If a dose is missed, it should be taken as soon as remembered on the same day. However, if it is near the time for the next scheduled dose, the missed dose should be skipped. Patients should never double the dose to make up for a missed administration. Consistent daily timing is important for maintaining stable serum levels, but minor variations are generally well-tolerated given digoxin’s long half-life.

Overdose

Digoxin overdose constitutes a medical emergency requiring immediate attention. Symptoms may include severe nausea and vomiting, visual disturbances, confusion, and life-threatening cardiac arrhythmias. Treatment involves discontinuation of digoxin, correction of electrolyte abnormalities, and cardiac monitoring. Digoxin immune fab (Digibind) is indicated for serious toxicity. Activated charcoal may be beneficial if administered soon after ingestion. Management should occur in a setting equipped for continuous cardiac monitoring and advanced life support.

Storage

Store at controlled room temperature (20-25°C or 68-77°F), protecting from light and moisture. Keep in the original container with the lid tightly closed. Do not transfer to other containers. Keep out of reach of children and pets. Properly discard any expired medication or medication no longer needed. Do not flush medications down the toilet or pour them into a drain unless instructed to do so.

Disclaimer

This information is intended for healthcare professionals and should not replace professional medical advice, diagnosis, or treatment. Always consult appropriate prescribing information and clinical guidelines before administration. Dosage must be individualized based on patient-specific factors. The prescriber should be familiar with the complete prescribing information and potential adverse effects. Regular monitoring is essential for safe use.

Reviews

Clinical experience spanning decades supports digoxin’s role in specific cardiac conditions when used appropriately. Many cardiologists note its continued value in difficult-to-control atrial fibrillation and as adjunctive therapy in heart failure. However, experts emphasize the critical importance of careful patient selection, appropriate dosing, and vigilant monitoring due to its narrow therapeutic index. Most specialists reserve its use for situations where benefits clearly outweigh risks and alternative therapies have proven insufficient or unsuitable.