Digoxin (Lanoxin) is a cardiac glycoside that is among the oldest medications used for heart failure.
What are its two primary actions?
Positive chronotropy and negative inotropy.
Negative inotropy and negative chronotropy.
Positive inotropy and negative chronotropy.
Positive inotropy and positive chronotropy.
The Correct Answer is C
Digoxin is a cardiac glycoside that increases the force of heart contractions (positive inotropy) and decreases the heart rate (negative chronotropy) by inhibiting the sodium-potassium ATPase pump in the cardiac cell membranes and affecting the autonomic tone. This helps to improve the symptoms of heart failure and to control the ventricular rate in atrial fibrillation.
Choice A is wrong because positive chronotropy means increasing the heart rate, which is the opposite of what digoxin does.
Choice B is wrong because negative inotropy means decreasing the force of heart contractions, which is also the opposite of what digoxin does.
Choice D is wrong because positive inotropy and positive chronotropy would both increase the workload of the heart, which is not desirable in heart failure or atrial fibrillation.
Normal ranges for digoxin are 0.5 to 2 ng/mL for heart failure and 0.8 to 2 ng/mL for atrial fibrillation. Digoxin has a narrow therapeutic window and can cause serious side effects if overdosed or underdosed.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Atorvastatin is a type ofstatin, which are the most potent antilipidemic agents, and have proven to lower the risk of myocardial infarction by reducing the levels of low-density lipoprotein (LDL) cholesterol and triglycerides in the blood.Statins also slightly increase the level of high-density lipoprotein (HDL) cholesterol, which is beneficial for cardiovascular health.
Choice B, niacin, is a type ofnicotinic acid, which can lower LDL cholesterol and triglycerides, and increase HDL cholesterol, but it is less effective than statins and has more side effects, such as flushing, itching, and liver toxicity.
Choice C, gemfibrozil, is a type offibric acid derivative, which can lower triglycerides and increase HDL cholesterol, but have little effect on LDL cholesterol.They are mainly used for patients with high triglyceride levels or low HDL cholesterol levels.
Choice D, amlodipine, is not an antilipidemic agent at all.It is a type ofcalcium channel blocker, which is used to treat hypertension and angina by relaxing the blood vessels and reducing the workload of the heart.
Correct Answer is B
Explanation
Diuretics are drugs that increase the amount of urine and salt (sodium) excreted by the kidneys. They are used to treat high blood pressure, heart failure, and edema (fluid retention). However, some diuretics can cause low levels of potassium in the blood (hypokalemia), which can lead to muscle weakness, cramps, and arrhythmias. To prevent this, a combination of diuretics acting on different parts of the kidney (such as a loop diuretic and a thiazide diuretic) may be prescribed.This way, the potassium-sparing effect of one diuretic can balance the potassium-wasting effect of the other, while still achieving a net sodium loss.
Choice A is wrong because they are not a part of the initial diuretic therapy.Combination diuretic therapy is usually reserved for patients who are resistant to or intolerant of monotherapy.
Choice C is wrong because little follow up is not needed after the initial treatment.Patients on combination diuretic therapy require close monitoring of their blood pressure, electrolytes, renal function, and weight to avoid adverse effects such as dehydration, hyponatremia, hypotension, and worsening renal function.
Choice D is wrong because they do not increase the risk of hypokalemia.As explained above, combination diuretic therapy aims to reduce the risk of hypokalemia by using a potassium-sparing diuretic along with a potassium-wasting diuretic.
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