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 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.
Correct Answer is B
Explanation
Class IV antidysrhythmics or calcium channel blockers decrease the flow of calcium ions into cardiac and vascular smooth muscle cells, thus decreasing heart rate and contractions.By reducing the calcium influx, they also decrease the slope of phase 0 and 4 and prolong phase 2 of the cardiac action potential.This results in vasodilation, reduced myocardial oxygen demand, and decreased conduction through the AV node.
Choice A is wrong because calcium channel blockers do not increase blood vessel spasm, but rather cause vasodilation.
Choice C is wrong because calcium channel blockers do not decrease refractory period, but rather prolong it by extending phase 2 of the cardiac action potential.
Choice D is wrong because calcium channel blockers do not increase heart rate, but rather decrease it by slowing down the pacemaker activity and AV nodal conduction.
Normal ranges for heart rate are 60 to 100 beats per minute, and for blood pressure are 120/80 mmHg or lower.
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