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 C
Explanation
Bile acid-binding resins are cholesterol-lowering agents that bind to bile acids in the intestine and prevent their reabsorption. This reduces the amount of bile acids available for cholesterol synthesis in the liver, which lowers the levels of LDL cholesterol in the blood. However, bile acids are also needed for the absorption of fat-soluble vitamins A, D, E, and K.Therefore, patients taking bile acid-binding resins may require supplements of these vitamins to prevent deficiency.
Choice A is wrong because nicotinic acid, or niacin, is a B vitamin that can lower cholesterol by limiting the production of fats in the liver.It does not affect the absorption of fat-soluble vitamins.
Choice B is wrong because nitroglycerin is not a cholesterol-lowering agent, but a vasodilator that relaxes the blood vessels and improves blood flow.It has no effect on fat-soluble vitamin absorption.
Choice D is wrong because beta blockers are not cholesterol-lowering agents, but drugs that lower blood pressure and heart rate by blocking the effects of adrenaline.They have no effect on fat-soluble vitamin absorption.
Correct Answer is D
Explanation
Choice A is wrong because calcium channel blockers (CCBs) are a class of drugs that prevent calcium from entering the cells of the heart and blood vessels, causing them to relax and lower blood pressure.
Examples of CCBs include amlodipine, diltiazem, verapamil, and nifedipine.CCBs are used to treat hypertension, angina, and arrhythmias.
Choice B is wrong because beta blockers are a class of drugs that reduce the heart rate and force of contraction, lowering the cardiac output and blood pressure.
Examples of beta blockers include atenolol, metoprolol, propranolol, and bisoprolol.Beta blockers are used to treat hypertension, angina, heart failure, and arrhythmias.
Choice C is wrong because platelet inhibitors are a class of drugs that prevent platelets from clumping together and forming blood clots.
Examples of platelet inhibitors include aspirin, clopidogrel, ticagrelor, and prasugrel.Platelet inhibitors are used to prevent or treat cardiovascular events such as heart attack or stroke.
Choice E is wrong because ACE inhibitors are a class of drugs that inhibit the enzyme that converts angiotensin I to angiotensin II, reducing the production of this vasoconstrictor hormone.
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