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
Hypokalemia is a condition of low potassium levels in the blood, which can be caused by diuretics such as furosemide (Lasix) that increase the excretion of potassium in the urine. Potassium is an important electrolyte that helps regulate the function of nerves and muscles, including the heart.Low potassium levels can cause symptoms such as confusion, tremors, muscle cramps, and nausea, which are consistent with the patient’s presentation.
Choice B, renal failure, is wrong because furosemide is used to treat fluid retention and edema caused by kidney disease, not to cause it.Renal failure would also cause symptoms such as decreased urine output, swelling, fatigue, and shortness of breath, which are not mentioned in the question.
Choice C, hyperkalemia, is wrong because hyperkalemia is a condition of high potassium levels in the blood, which can be caused by kidney disease or certain medications that decrease the excretion of potassium in the urine.Hyperkalemia can cause symptoms such as weakness, irregular heartbeat, paralysis, and chest pain, which are different from the patient’s symptoms.
Choice D, heart failure, is wrong because furosemide is also used to treat fluid retention and edema caused by heart failure, not to cause it.Heart failure would also cause symptoms such as shortness of breath, coughing, fatigue, and rapid weight gain, which are not mentioned in the question.
Normal ranges for potassium levels in the blood are 3.5 to 5.0 milliequivalents per liter (mEq/L) for adults and 3.4 to 4.7 mEq/L for children.
A level below 3.5 mEq/L is considered hypokalemic and a level above 5.0 mEq/L is considered hyperkalemic.
Correct Answer is C
Explanation
Nitrates are a class of drugs that help to widen the blood vessels and increase blood flow to the heart muscle, which reduces the chest pain or discomfort caused by angina.Nitrates can be taken as a mouth spray or tablets that dissolve under the tongue during an angina attack, or as a preventive measure before physical activity.
Choice A is wrong because fatty oxidase enzyme inhibitors are not a real class of drugs.
Fatty acid oxidation is a process that breaks down fats for energy, and it is not related to angina treatment.
Choice B is wrong because beta adrenergic blockers are not the main class of drugs for angina treatment, although they can be used to prevent angina attacks by slowing down the heart rate and reducing the blood pressure.
Beta blockers block the effects of epinephrine (adrenaline) on the heart and blood vessels, which reduces the oxygen demand of the heart.
Choice D is wrong because statins are not used to treat angina attacks, but to lower the cholesterol levels in the blood and prevent plaque buildup in the arteries.
Statins can help reduce the risk of heart attacks and strokes in people with angina, but they do not relieve angina symptoms.
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