A patient with atrial fibrillation has been prescribed digoxin (Lanoxin). The nurse should monitor which laboratory value to evaluate therapeutic effectiveness?
Serum potassium level
Serum sodium level
Serum magnesium level
Serum calcium level.
The Correct Answer is A
Digoxin (Lanoxin) is a cardiac glycoside that is used to treat atrial fibrillation and heart failure.
It works by increasing the force of cardiac contraction and slowing down the heart rate.
However, digoxin can also cause toxicity, which can lead to life-threatening arrhythmias.
One of the risk factors for digoxin toxicity is hypokalemia, or low serum potassium level.
Potassium is an electrolyte that is essential for normal cardiac function and conduction. When the serum potassium level is low, digoxin binds more strongly to the cardiac cells and increases its effects, which can result in bradycardia, heart block, or ventricular tachycardia.
Therefore, the nurse should monitor the serum potassium level to evaluate the therapeutic effectiveness and safety of digoxin therapy.
Choice B) Serum sodium level is wrong because sodium is not directly related to digoxin action or toxicity.
Sodium is another electrolyte that is important for fluid balance and blood pressure regulation. However, sodium does not affect the binding of digoxin to the cardiac cells or its effects on the heart rate and contractility.
Therefore, the nurse does not need to monitor the serum sodium level to evaluate digoxin therapy.
Choice C) Serum magnesium level is wrong because magnesium is not directly related to digoxin action or toxicity.
Magnesium is another electrolyte that is involved in many enzymatic reactions and neuromuscular function. However, magnesium does not affect the binding of digoxin to the cardiac cells or its effects on the heart rate and contractility.
Therefore, the nurse does not need to monitor the serum magnesium level to evaluate digoxin therapy.
Choice D) Serum calcium level is wrong because calcium is not directly related to digoxin action or toxicity.
Calcium is another electrolyte that is essential for bone health and muscle contraction. However, calcium does not affect the binding of digoxin to the cardiac cells or its effects on the heart rate and contractility.
Therefore, the nurse does not need to monitor the serum calcium level to evaluate digoxin therapy.
The normal range for serum potassium level is 3.5-5.0 mEq
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
This is because diltiazem (Cardizem) is a calcium channel blocker that lowers blood pressure and can cause orthostatic hypotension, which is a sudden drop in blood pressure when standing up from a sitting or lying position. This can lead to dizziness and lightheadedness, which can increase the risk of falls and injuries. Changing positions slowly can help prevent or reduce these symptoms by allowing the body to adjust to the change in blood pressure.
Choice A) Administer diltiazem as ordered by physician is wrong because it does not address the patient’s complaint of dizziness and lightheadedness, which are side effects of the medication.
The nurse should monitor the patient’s blood pressure and heart rate before and after administering diltiazem, and report any abnormal findings to the physician.
Choice C) Notify physician immediately is wrong because it is not necessary to notify the physician immediately for a common and mild side effect of diltiazem, unless the patient has other signs of severe hypotension, such as fainting, chest pain, or confusion.
The nurse should educate the patient about the possible side effects of diltiazem and how to prevent or manage them.
Choice D) Hold diltiazem and notify physician if symptoms persist is wrong because it is not appropriate to hold a prescribed medication without a valid reason or an order from the physician.
Holding diltiazem could cause the patient’s blood pressure to rise and increase the risk of complications from atrial fibrillation, such as stroke or heart failure.
The nurse should administer diltiazem as ordered and monitor the patient’s response.
Correct Answer is A
Explanation
The nurse should monitor the serum potassium level to determine the therapeutic effectiveness of digoxin (Lanoxin), a cardiac glycoside that improves the contractility and pumping ability of the heart. Digoxin has a narrow therapeutic range and can cause toxicity if the serum level is too high or if the patient has hypokalemia (low potassium).Hypokalemia can result from diuretic therapy, which is often prescribed for heart failure patients to reduce fluid overload.
Therefore, the nurse should monitor the serum potassium level and report any abnormal values to the provider.The normal potassium level is 3.5 to 5.0 mEq/L.
Choice B) Serum sodium level is wrong because sodium level is not directly affected by digoxin therapy.
Sodium level may be altered in heart failure patients due to fluid retention or diuretic use, but it does not indicate the effectiveness of digoxin.
Choice C) Serum magnesium level is wrong because magnesium level is not directly affected by digoxin therapy.
Magnesium level may be altered in heart failure patients due to diuretic use or renal impairment, but it does not indicate the effectiveness of digoxin.
Choice D) Serum calcium level is wrong because calcium level is not directly affected by digoxin therapy.
Calcium level may be altered in heart failure patients due to renal impairment or vitamin D deficiency, but it does not indicate the effectiveness of digoxin.
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