Which of the following electrolytes should monitor in a patient with congestive heart failure receiving digox… - NORCET -4 , 2023

NORCET -4 , 2023

Pharmacology

Medium

Appeared in: NORCET -4 , 2023

Explanation

Furosemide is a loop diuretic, which works by inhibiting the reabsorption of sodium and chloride in the loop of Henle, leading to increased excretion of water and electrolytes.
A primary side effect of furosemide is the loss of potassium, which can lead to hypokalemia (serum potassium less than 3.5 mEq/L).
Digoxin's therapeutic and toxic effects are influenced by potassium levels. Potassium and digoxin compete for the same binding sites on the Na+/K+-ATPase pump in cardiac cells.
When potassium levels are low (hypokalemia), more binding sites are available for digoxin, increasing its effect and significantly raising the risk of digoxin toxicity.
Digoxin toxicity can manifest as life-threatening cardiac dysrhythmias, making the monitoring of potassium levels a top priority.

Option A: While furosemide does cause sodium excretion (natriuresis) and can lead to hyponatremia, fluctuations in sodium levels do not directly potentiate the toxic effects of digoxin in the same critical way that low potassium does.
Option B: Furosemide increases the urinary excretion of calcium, which can lead to hypocalcemia. However, it is hypercalcemia (high calcium), not hypocalcemia, that increases the risk of digoxin toxicity. Therefore, monitoring calcium is less critical in this specific interaction.
Option D: Zinc is a trace mineral and is not significantly affected by furosemide therapy, nor does it have a direct and critical interaction with digoxin that would necessitate routine monitoring in this context.

Visual 1: Diagram - A diagram illustrating the Na+/K+-ATPase pump on a cardiac muscle cell, showing how low extracellular potassium allows for increased binding of digoxin, leading to toxicity.
Visual 2: ECG Strip - An image showing ECG changes characteristic of hypokalemia (e.g., flattened T-waves, prominent U-waves) and digoxin toxicity (e.g., ST-segment depression, various arrhythmias).

Clinical Relevance

Nursing practice connection: Use the key finding related to Drug interaction between diuretics and cardiac glycosides, and associated electrolyte monitoring to guide bedside assessment, documentation, and the next nursing action.
A nurse's primary responsibility is to anticipate and prevent adverse drug reactions. Knowing that furosemide wastes potassium and that hypokalemia potentiates digoxin toxicity is a fundamental patient safety concept.
Nurses must educate patients on the signs of both hypokalemia (muscle weakness, fatigue, constipation) and digoxin toxicity (anorexia, nausea, vomiting, visual changes, confusion) and instruct them to report these symptoms immediately.
Nurses should also teach patients about dietary sources of potassium (e.g., bananas, potatoes, spinach) to help manage potassium levels.

How to Approach the Question

First, identify the drugs mentioned in the question: digoxin and furosemide.
Recall the drug class and primary mechanism of each. Furosemide is a loop diuretic, and digoxin is a cardiac glycoside.
Think about the major side effects and electrolyte imbalances associated with each drug. Furosemide is well-known for causing potassium loss (hypokalemia).
Consider how the side effects of one drug might interact with the other. The key interaction here is that furosemide-induced hypokalemia increases the risk of digoxin toxicity.
Evaluate the options based on this critical interaction. Potassium is the electrolyte most directly and dangerously involved, making it the priority for monitoring.

Concept Tested & Keywords

Concept Tested: Drug interaction between diuretics and cardiac glycosides, and associated electrolyte monitoring.
Stem keywords: congestive heart failure, digoxin, furosemide, electrolyte
Lead-in keywords: Which
Clinical cues: The combination of digoxin and furosemide is a major clinical cue, as this pairing is well-known for its potential to cause digoxin toxicity secondary to hypokalemia.

QrHjneh0f4OiS5fNhmqBbd