Which drug class should not be used when a patient is taking nitrates?

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.

The nurse should contact the provider before administering furosemide because the patient has a low serum potassium level of 2.8 mEq/L, which is below the normal range of 3.5 to 5.0 mEq/L.Furosemide is a diuretic that can cause potassium loss and worsen hypokalemia, which can lead to cardiac arrhythmias, muscle weakness, and fatigue. The nurse should also monitor the patient’s blood pressure, weight, and urine output, as furosemide can lower blood pressure and cause dehydration.

Choice A. Administer medication is wrong because the nurse should not give furosemide without checking with the provider first, as it could be harmful to the patient with low potassium.

Choice C. Hold medication is wrong because the nurse should not withhold furosemide without a valid reason or an order from the provider, as it could cause fluid overload and worsen the patient’s condition.

Choice D. Give potassium supplement is wrong because the nurse should not give potassium supplement without an order from the provider, as it could cause hyperkalemia or interact with other medications.