Question

A patient on digoxin therapy accidentally consumes 8 tablets of digoxin 0.25 mg. Two hours later, he presented to the emergency doctor with a heart rate of 54 bpm and ECG evidence of third-degree AV block. What is the immediate management of this patient?

• A. Digoxin immune fab
• B. Lignocaine
• C. Phenytoin
• D. DC cardioversion

Hint:

Digoxin immune fab is the specific antidote for digoxin toxicity and is used in cases of severe toxicity with symptoms such as heart block and bradycardia.

Answer 1

The Correct Option is A

The scenario involves a patient experiencing an overdose of digoxin, a cardiac glycoside often used in heart failure and to control the heart rate in atrial fibrillation. The patient has taken an excessive dose and presents with a significantly low heart rate (54 bpm) and third-degree AV block, both of which are serious symptoms indicating digoxin toxicity.

Step-by-step Management Approach:

1. Recognition of Digoxin Toxicity: The symptoms presented (bradycardia and AV block) are classical signs of digoxin toxicity. Digoxin affects the conduction system of the heart, leading to such bradyarrhythmias.
2. Understanding the Role of Digoxin Immune Fab: Digoxin immune fab (also known as digoxin-specific antibody fragments) works by binding to digoxin, forming complexes that are then excreted by the kidneys. This effectively neutralizes the digoxin, relieving the toxic effects.
3. Immediate Management: In cases of life-threatening digoxin toxicity, especially with arrhythmias like third-degree AV block, the administration of digoxin immune fab is the treatment of choice. It rapidly reverses the effects of toxicity.
4. Ruling Out Other Options:
   • Lignocaine: Typically used to treat ventricular arrhythmias, not suitable for treating AV block due to digoxin.
   • Phenytoin: Occasionally used for digoxin-induced ventricular arrhythmias but not the first-line treatment for AV block in digoxin toxicity.
   • DC Cardioversion: Contraindicated in digoxin toxicity as it may worsen the arrhythmias.

Conclusion: The immediate and most appropriate management for this patient, experiencing severe digoxin toxicity causing bradycardia and complete heart block, is the administration of Digoxin immune fab.