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 ["A","B","C","E"]
Explanation
Captopril is an angiotensin-converting enzyme (ACE) inhibitor that is used to treat heart failure by lowering blood pressure and reducing the workload on the heart.
The nurse should include the following instructions when teaching a client who is prescribed captopril:
• Avoid salt substitutes that contain potassium.Captopril can increase the potassium levels in the blood, which can lead to hyperkalemia.Salt substitutes that contain potassium can further increase the risk of hyperkalemia, which can cause cardiac arrhythmias and muscle weakness.
• Report any dry cough to the provider.A dry cough is a common side effect of captopril and other ACE inhibitors.It is caused by the accumulation of bradykinin, a substance that dilates blood vessels and causes inflammation in the lungs.
The cough can be annoying and interfere with sleep and quality of life.The provider may switch the client to another type of medication if the cough is bothersome.
• Take the medication on an empty stomach.Food can decrease the absorption and effectiveness of captopril.The client should take the medication at least 1 hour before or 2 hours after meals.
• Rise slowly from a sitting or lying position.Captopril can cause orthostatic hypotension, which is a sudden drop in blood pressure when changing positions.
This can lead to dizziness, fainting, and falls.The client should rise slowly and sit on the edge of the bed for a few minutes before standing up.
Choice D is wrong because drinking at least 3 L of fluids per day is not recommended for clients with heart failure.
Excessive fluid intake can worsen the symptoms of heart failure, such as edema, shortness of breath, and fatigue.The client should limit fluid intake to 2 L or less per day, unless instructed otherwise by the provider.
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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