Which of the following drugs is withheld if the patient's pulse is less than 60/min?

AIIMS Raipur - 2017 (Shift-3)

Pharmacology

Easy

Appeared in: AIIMS Raipur - 2017 (Shift-3)

Explanation

Digoxin is a cardiac glycoside that has a negative chronotropic effect, meaning it slows down the heart rate.
Administering digoxin to a patient with a pulse already below 60 bpm can induce severe bradycardia or atrioventricular (AV) block, which is a life-threatening condition.
A critical nursing safety protocol is to measure the apical pulse for a full minute before giving digoxin and to withhold the dose if the rate is below the established threshold (typically 60 bpm for adults).
Clinical manifestations of digoxin toxicity include bradycardia, along with other symptoms like nausea, vomiting, and visual disturbances.

Option B: Dobutamine is a beta-1 adrenergic agonist. Its primary action is to increase heart rate and myocardial contractility.
Option C: Dopamine is a catecholamine and vasopressor. Depending on the dose, it increases heart rate, contractility, and blood pressure.
Option D: Phenytoin is an anticonvulsant medication used to treat seizures. Its primary monitoring does not involve holding the dose for a pulse rate below 60 bpm.

Visual 1: Infographic - A step-by-step guide on how to accurately measure an apical pulse for one full minute using a stethoscope. This reinforces the key nursing action required before administering digoxin.
Visual 2: Chart - A clear chart showing the different pulse rate thresholds for withholding digoxin in various age groups: adults (<60 bpm), children (<70 bpm), and infants (<90 bpm). This provides a quick reference for safe practice.

Clinical Relevance

Nursing practice connection: Knowing Medication Administration and Safety helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
This question highlights a fundamental patient safety principle in medication administration: the importance of pre-assessment. Failing to check the pulse before giving digoxin can lead to serious patient harm.
Nurses must not only perform this check but also document the pulse rate and their action (giving or holding the drug) and promptly report any deviation to the healthcare provider.
What if? If the patient is also taking a beta-blocker (e.g., metoprolol) or a calcium channel blocker (e.g., verapamil), the risk of severe bradycardia when combined with digoxin is significantly higher. This requires even more vigilant monitoring and possibly a lower dose or different medication choice by the provider.

How to Approach the Question

First, analyze the question's core requirement: identifying a drug that is held for a low pulse rate (bradycardia). The specific value given is <60/min, which is the standard threshold for adults.
Next, review the options and recall the primary pharmacological action of each drug on the cardiovascular system.
Consider Digoxin: Recall that it is a cardiac glycoside known for slowing the heart rate. This makes it a strong candidate.
Consider Dobutamine and Dopamine: Recall that these are sympathomimetics (catecholamines) used to increase heart rate and contractility. This makes them incorrect.
Consider Phenytoin: Recall that it is an anticonvulsant. While it has potential cardiac side effects with rapid IV use, it's not primarily known for requiring a pulse check before routine oral administration.
Based on this analysis, conclude that Digoxin is the only drug on the list for which withholding based on a pulse <60/min is a standard, critical safety practice.

Concept Tested & Keywords

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