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
ACE inhibitors are a type of medication used to treat high blood pressure and heart failure. They work by blocking the production of a hormone called angiotensin II, which narrows the blood vessels and increases blood pressure.By preventing this hormone from acting, ACE inhibitors lower blood pressure and reduce the workload on the heart. One of the most common side effects of ACE inhibitors is a dry cough, which occurs in 12–19% of people who take them. The cough is caused by the accumulation of a substance called bradykinin, which is normally broken down by angiotensin-converting enzyme (ACE).When ACE is inhibited, bradykinin levels increase and cause irritation and inflammation in the airways.
Choice A is wrong because decreased white blood cells are not a common side effect of ACE inhibitors.
However, some people may develop a condition called neutropenia, which is a low level of a type of white blood cell called neutrophils.This can increase the risk of infections and may require stopping the medication.
Choice B is wrong because swelling of the face and lips is not a common side effect of ACE inhibitors.
However, some people may develop a rare but serious allergic reaction called angioedema, which is a swelling of the deeper layers of the skin and mucous membranes.
This can affect the face, lips, tongue, throat, or other parts of the body and can cause difficulty breathing or swallowing.Angioedema can be life-threatening and requires immediate medical attention.
Choice D is wrong because renal failure is not a common side effect of ACE inhibitors.
However, some people may experience a decrease in kidney function or an increase in blood levels of creatinine, which is a waste product filtered by the kidneys.
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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