An example of a cardiac glycoside?

Appeared in: NHM UP Staff Nurse - 2016

Explanation

Digoxin is a cardiac glycoside, a class of drugs derived from the Digitalis (foxglove) plant.
Its primary mechanism is the inhibition of the Na+/K+-ATPase pump in cardiac cells, which increases intracellular calcium and enhances myocardial contractility (positive inotropic effect).
It is used to improve cardiac output in heart failure and to control the ventricular rate in atrial fibrillation by slowing conduction through the AV node.

Option A: Nifedipine is a dihydropyridine calcium channel blocker, not a cardiac glycoside. It works by relaxing vascular smooth muscle, leading to vasodilation.
Option B: Lidocaine is a Class IB antiarrhythmic agent. It works by blocking sodium channels, primarily in ventricular tissue, to suppress arrhythmias.
Option C: Procainamide is a Class IA antiarrhythmic agent. It blocks sodium channels and prolongs the action potential duration to treat a variety of arrhythmias.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacology: Classification of Cardiac Drugs as background academic context rather than a clinical decision trigger.
A critical nursing responsibility is monitoring for Digoxin toxicity due to its narrow therapeutic index. Early signs like nausea, vomiting, and anorexia must be reported immediately.
Before administering Digoxin, the nurse must assess the patient's apical pulse for one full minute. The dose is typically held and the provider notified if the pulse is below 60 bpm for an adult.
Electrolyte levels, especially potassium, must be closely monitored. Hypokalemia (low potassium) significantly increases the risk of Digoxin toxicity.

How to Approach the Question

First, identify the key term in the question: 'cardiac glycoside'. This is a specific drug classification.
This is a factual recall question. You need to access your knowledge of pharmacological drug classes.
Systematically review each option and classify it.
Option A, Nifedipine, is a calcium channel blocker.
Option B, Lidocaine, is a Class IB antiarrhythmic.
Option C, Procainamide, is a Class IA antiarrhythmic.

Concept Tested & Keywords

QuVgJ3QQtg09U5Q6KDesDh

E6 Pharmacology Katzung 16e p. 335-337

E6 Pharmacology KD Tripathi Essentials 9e Part 2 pp. 187-189, 191-193

Practise the full NHM UP Staff Nurse - 2016

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