A nurse in a provider's office is monitoring blood electrolytes for four clients who take digoxin.
Which of the following electrolyte values increases a client's risk for digoxin toxicity?
Potassium 3.0 mEq/L.
Calcium 9.2 mg/dL.
Sodium 140 mEq/L.
Magnesium 2.2 mg/dL.
The Correct Answer is A
This is because low potassium levels (hypokalemia) increase the sensitivity of the heart to digoxin and can lead to toxicity even with normal serum digoxin levels. Digoxin inhibits the sodium-potassium pump on the cardiac cells, which causes potassium to accumulate outside the cells. Low potassium levels in the blood create a larger gradient for potassium to move out of the cells, which enhances the effect of digoxin and can cause arrhythmias.
Choice B is wrong because calcium 9.2 mg/dL is within the normal range (8.5 to 10.2 mg/dL) and does not increase the risk of digoxin toxicity. However, high calcium levels (hypercalcemia) can potentiate the effects of digoxin and cause toxicity.
Choice C is wrong because sodium 140 mEq/L is within the normal range (135 to 145 mEq/L) and does not increase the risk of digoxin toxicity. However, high sodium levels (hypernatremia) can reduce the binding of digoxin to the sodium-potassium pump and decrease its efficacy.
Choice D is wrong because magnesium 2.2 mg/dL is within the normal range (1.7 to 2.4 mg/dL) and does not increase the risk of digoxin toxicity. However, low magnesium levels (hypomagnesemia) can increase the sensitivity of the heart to digoxin and cause toxicity.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Erectile dysfunction drugs should not be used when a patient is taking nitrates.This is because both types of drugs cause blood vessels to dilate, which can lead to a dangerous drop in blood pressure. This can increase the risk of heart attack, stroke or fainting.
Choice B is wrong because alpha-adrenergic blockers are sometimes used together with nitrates to treat high blood pressure and angina. They work by relaxing the smooth muscles of the blood vessels, which lowers blood pressure and improves blood flow.
Choice C is wrong because calcium channel blockers are also used to treat high blood pressure and angina. They work by blocking the entry of calcium into the muscle cells of the heart and blood vessels, which reduces the force of contraction and relaxes the blood vessels.
Choice D is wrong because beta-adrenergic blockers are another class of drugs that can be used with nitrates to treat high blood pressure and angina. They work by blocking the effects of adrenaline on the heart and blood vessels, which slows down the heart rate and lowers blood pressure.
Normal ranges for blood pressure vary depending on age, gender and other factors, but generally they are between 90/60 mmHg and 120/80 mmHg for healthy adults.
Correct Answer is D
Explanation
Thrombolytic agents are a classification of drugs that dissolve blood clots by activating the enzyme plasmin, which breaks down the proteins (fibrins) that form clots. They are used for serious conditions, such as stroke, pulmonary embolism, or heart attack when the blood flow needs to be restored quickly.
Choice A is wrong because salicylates are anti-inflammatory drugs that inhibit the synthesis of prostaglandins, which are involved in inflammation and pain. They also have antiplatelet effects, but they do not dissolve existing clots.
Choice B is wrong because antiplatelets are drugs that prevent platelets from sticking together and forming clots. They are used to prevent clotting in conditions such as coronary artery disease, stroke, or peripheral arterial disease. They do not dissolve existing clots either.
Choice C is wrong because anticoagulants are drugs that prevent clots from forming by interfering with the clotting factors that are normally present in the blood.
They are used to treat or prevent conditions such as deep vein thrombosis, pulmonary embolism, or atrial fibrillation. They do not dissolve existing clots.
Normal ranges for clotting factors vary depending on the laboratory and the method used, but some common values are:
• Prothrombin time (PT): 11 to 13 seconds
• International normalized ratio (INR): 0.8 to 1.2
• Activated partial thromboplastin time (aPTT): 25 to 35 seconds
• Fibrinogen: 200 to 400 mg/dL
• D-dimer: less than 0.5 mcg/mL
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