Which of the following is the main function of Digitalis Drug?

Appeared in: AIIMS Bhopal NO - 2018 (Shift-1st)

Explanation

The primary function of Digitalis (a cardiac glycoside) is to produce a positive inotropic effect.
A positive inotropic effect means the drug increases the force and velocity of myocardial contraction.
This action is achieved by inhibiting the Na+/K+ ATPase pump in cardiac cells, which leads to increased intracellular calcium and enhanced contractility.
The stronger contraction improves cardiac output, which is the main therapeutic goal in treating heart failure.

Option A: This is a result of the drug's primary action, not the action itself. The direct function is increasing contractility, which in turn improves circulation.
Option C: This is incorrect. Digitalis enhances cardiac activity, specifically the force of contraction. Drugs that prevent cardiac activity (e.g., for cardioplegia in surgery) have a completely different purpose and mechanism.
Option D: This is the opposite of the drug's main inotropic effect. While Digitalis does decrease the heart rate (a negative chronotropic effect), its defining function is to increase contractility.

Clinical Relevance

Nursing practice connection: Knowing Pharmacology: Mechanism of Action of Digitalis helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Digitalis has a narrow therapeutic index (0.5 to 2 ng/mL), meaning the dose that is effective is very close to the dose that is toxic. Nurses must monitor patients closely for signs of toxicity.
Key nursing action: Always check the apical pulse for a full minute before administering Digitalis. Withhold the dose and notify the provider if the heart rate is below 60 bpm in an adult.
Signs of Digitalis toxicity include nausea, vomiting, anorexia, fatigue, confusion, and visual disturbances (e.g., seeing yellow-green halos around objects).

How to Approach the Question

First, identify the core subject of the question, which is the 'main function' of the 'Digitalis Drug'.
This is a factual recall question from pharmacology. Access your knowledge about cardiac medications.
Recall that Digitalis is a cardiac glycoside. What is this class of drugs known for?
Evaluate the options. 'Increase myocardial contractility' is the definition of a positive inotropic effect, which is the hallmark of cardiac glycosides.
Eliminate the other options. 'Maintain circulation' is a result, not a function. 'Prevent' and 'decrease' cardiac activity are incorrect or opposite to the drug's primary purpose.

Concept Tested & Keywords

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E6 Pharmacology KD Tripathi Essentials 9e Part 2 p. 188-190

E6 Pharmacology Nursing Lilley 11e Part 2 p. 73-75

E6 Physiology Guyton 4SAE Part 2A p. 20-22

Practise the full AIIMS Bhopal NO - 2018 (Shift-1st)

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