Function of Digitalis Drug?

PGIMER Chandigarh NO - 2015

Pharmacology

Easy

Appeared in: PGIMER Chandigarh NO - 2015

Explanation

Digitalis is a positive inotropic agent, meaning it increases the force and velocity of myocardial contractions.
This effect is achieved by inhibiting the Na+/K+ ATPase enzyme in cardiac cells, which leads to an increase in intracellular calcium levels.
The increased intracellular calcium enhances the contractile process of the heart muscle, improving its pumping efficiency.
This action makes it effective in treating systolic heart failure by increasing cardiac output.

Option A: This statement is too vague and non-specific. While the ultimate goal of cardiac medications is to improve circulation, this option does not describe the direct pharmacological mechanism of Digitalis.
Option C: This is the direct opposite of the primary effect of Digitalis. Drugs that decrease myocardial contractility are known as negative inotropes.
Option D: The intended therapeutic effect of Digitalis in heart failure is to increase the cardiac index and cardiac output by strengthening contractions. A decrease in the cardiac index would indicate worsening heart function or potential drug toxicity.

Clinical Relevance

Nursing practice connection: Knowing Pharmacological action of Digitalis (cardiac glycoside) helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
A critical nursing responsibility before administering Digitalis (digoxin) is to check the patient's apical pulse for one full minute. The dose must be held and the provider notified if the rate is below 60 beats/minute in an adult, as the drug has a negative chronotropic effect.
Nurses must diligently monitor serum potassium levels because hypokalemia (low potassium) significantly increases the risk of Digitalis toxicity. This is especially important for patients concurrently taking potassium-wasting diuretics.
Recognizing the signs of Digitalis toxicity is a key patient safety role. Early symptoms include anorexia, nausea, and vomiting, while later signs can include visual disturbances (like seeing yellow-green halos) and life-threatening arrhythmias.

How to Approach the Question

First, identify the core of the question. It asks for the primary 'function' of the Digitalis drug, which is a direct question about its pharmacological action.
Recall the drug class: Digitalis is a cardiac glycoside. This class is famous for its effect on the force of heart contractions.
Evaluate the options in the context of cardiac pharmacology. The term 'myocardial contractility' refers to the heart muscle's squeezing force.
Connect the drug to its known effect. Digitalis is a 'positive inotrope,' which means it increases contractility. Therefore, 'Increase myocardial contractility' is the most accurate description of its function.
Systematically eliminate the other options. 'Decrease contractility' is the opposite effect. 'Maintain circulation' is too general and not a specific mechanism. 'Decrease cardiac index' is an adverse outcome, not the intended therapeutic function.

Concept Tested & Keywords

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