Which drugs act on the sympathetic nervous system, which regulates blood pressure by controlling heart rate, cardiac output, vascular tone, and renin release?

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.

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.