Which of the following is an antiarrhythmic drug?

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

Explanation

Amiodarone is a Class III antiarrhythmic drug according to the Vaughan Williams classification.
Its primary mechanism is blocking potassium channels, which prolongs the action potential duration and the effective refractory period in cardiac tissues.
This action makes it effective for treating a wide range of both supraventricular (like atrial fibrillation) and ventricular arrhythmias (like ventricular tachycardia).

Option A: Alteplase is a thrombolytic (fibrinolytic) agent, not an antiarrhythmic. Its function is to dissolve existing blood clots.
Option B: Amlodipine is a dihydropyridine calcium channel blocker used primarily for hypertension and angina. It has minimal effect on cardiac conduction compared to non-dihydropyridine calcium channel blockers.
Option D: Atropine is an anticholinergic drug used to increase a slow heart rate (bradycardia). It is not used to suppress fast, irregular rhythms (tachyarrhythmias).

Clinical Relevance

Nursing practice connection: Knowing Pharmacology: Classification of Antiarrhythmic Drugs helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Amiodarone is a potent but high-risk medication. Nurses must monitor for its numerous and serious side effects.
Key monitoring includes continuous ECG for QT prolongation and bradycardia, blood pressure for hypotension, and regular lab tests for thyroid (TSH), liver (LFTs), and pulmonary function (PFTs) during long-term therapy.
Patient education is critical, focusing on the need to report symptoms like shortness of breath, persistent cough (pulmonary toxicity), yellowing of skin (hepatotoxicity), and to use sun protection due to photosensitivity.

How to Approach the Question

First, identify the core of the question, which is to find the 'antiarrhythmic drug' among the options.
Systematically review each option and recall its primary drug class and therapeutic use.
Analyze Option A: Alteplase. Recognize it as a thrombolytic ('clot-buster'), which is a different function.
Analyze Option B: Amlodipine. Recall it's a calcium channel blocker for hypertension, primarily affecting blood vessels.
Analyze Option D: Atropine. Identify it as a drug used to speed up a slow heart, not suppress a fast one.
Analyze Option C: Amiodarone. Recall this is a cornerstone drug for treating various tachyarrhythmias.

Concept Tested & Keywords

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E6 Pharmacology Nursing Lilley 11e Part 2 p. 94-96

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

E6 Pharmacology Katzung 16e p. 375-377

Practise the full SCTIMST Staff Nurse - 2015 (Set-B)

Attempt every question from this paper in a timed mock, then review the full solution for each one.