Which one of the following is the drug of choice in ventricular arrhythmias?

SCTIMST Staff Nurse - 2015 (Set-A)

Pharmacology

Easy

Appeared in: SCTIMST Staff Nurse - 2015 (Set-A)

Explanation

Amiodarone is a potent, broad-spectrum Class III antiarrhythmic agent, although it possesses properties of all four Vaughan Williams classes.
It is highly effective for managing and terminating life-threatening ventricular arrhythmias, including ventricular tachycardia (VT) and ventricular fibrillation (VF).
According to Advanced Cardiac Life Support (ACLS) guidelines, amiodarone is a primary drug for shock-refractory VF/pulseless VT and for managing stable wide-complex tachycardia.
Its primary mechanism is blocking potassium channels, which prolongs the action potential duration and the effective refractory period, thereby terminating reentrant circuits.

Option A: Inderal (propranolol) is a Class II antiarrhythmic (beta-blocker). Its main role is in controlling heart rate in supraventricular tachycardias and suppressing arrhythmias caused by excessive sympathetic stimulation. It is not the first-line agent for terminating an active ventricular arrhythmia.
Option B: Digoxin is a cardiac glycoside used to improve contractility in heart failure and slow the ventricular rate in atrial fibrillation. It is not indicated for ventricular arrhythmias and can be proarrhythmic, meaning it can potentially worsen them.
Option C: Sorbitrate (isosorbide dinitrate) is a nitrate vasodilator. Its function is to relieve angina (chest pain) by dilating coronary arteries and reducing myocardial oxygen demand. It has no antiarrhythmic properties.

Clinical Relevance

Nursing practice connection: Prioritize focused assessment, early escalation, and real-time monitoring when managing Pharmacological management of ventricular arrhythmias in acute care settings.
Nurses administering IV amiodarone must use an infusion pump for precise delivery and provide continuous ECG and blood pressure monitoring due to the high risk of hypotension and bradycardia.
Long-term oral amiodarone therapy carries a risk of significant organ toxicity. Nurses must educate patients on the need for regular follow-up and monitoring of pulmonary, liver, and thyroid function.
Amiodarone has significant interactions with other common drugs, notably warfarin (increases bleeding risk) and digoxin (increases toxicity risk). Nurses must be vigilant in reviewing medication lists and monitoring for interaction effects.

How to Approach the Question

First, identify the key clinical condition in the question stem: 'ventricular arrhythmias'. This is a serious, often life-threatening heart rhythm disturbance.
Next, analyze the lead-in phrase 'drug of choice', which asks for the most appropriate or first-line agent among the options.
Systematically review each option and recall its drug class and primary clinical indication.
Inderal (propranolol) is a beta-blocker, mainly for rate control in atrial fibrillation or SVT.
Digoxin is a cardiac glycoside for heart failure and atrial fibrillation rate control.
Sorbitrate is a nitrate for angina (chest pain).

Concept Tested & Keywords

QlJTQ2-tv0FSRM57MxoJxY

E6 Pharmacology KD Tripathi Essentials 9e Part 2 p. 209-211

E6 Pharmacology Nursing Lilley 11e Part 2 p. 95-97

E6 Pharmacology Katzung 16e p. 375-377