A patient will be starting therapy with a corticosteroid. The nurse reviews the prescriber's orders and notes that an interaction may occur if the corticosteroid is taken with which of these drug classes?

The correct answer is c. 2,525 mL.

Choice A reason:

1,350 mL is calculated by considering only the lactated Ringer’s IV intake. The calculation is as follows:

• Lactated Ringer’s IV at 150 mL/hr for 9 hr: 150 mL/hr × 9 hr = 1,350 mL. This option does not include the intake from cefazolin, packed RBCs, sodium chloride boluses, or famotidine.

Choice B reason:

1,600 mL is not a correct calculation based on the given intake. This value does not accurately sum up any combination of the provided intake components.

Choice C reason:

2,525 mL is the correct total intake. The detailed calculation is:

• Lactated Ringer’s IV at 150 mL/hr for 9 hr: 150 mL/hr × 9 hr = 1,350 mL.
• Cefazolin in 100 mL of 0.9% sodium chloride: 100 mL.
• Two units of packed RBCs: 275 mL + 250 mL = 525 mL.
• Two IV bolus infusions of 250 mL of 6.0% sodium chloride: 250 mL + 250 mL = 500 mL.
• Famotidine in 50 mL of 0.9% sodium chloride: 50 mL.

Adding these together: 1,350 mL + 100 mL + 525 mL + 500 mL + 50 mL = 2,525 mL.

Choice D reason:

2,100 mL is not a correct calculation based on the given intake. This value does not accurately sum up any combination of the provided intake components.

Choice A reason: This is incorrect because sildenafil and nitrates do not affect each other's effectiveness, but rather their side effects. Sildenafil is a phosphodiesterase-5 inhibitor that enhances the effect of nitric oxide, which causes vasodilation and increases blood flow to the penis. Nitrates are vasodilators that also increase nitric oxide levels and reduce the workload of the heart.

Choice B reason: This is incorrect because sildenafil and nitrates do not cause a significant increase in pulse rate, but rather a decrease. This is because the vasodilation caused by both drugs lowers the blood pressure and the cardiac output, which reduces the heart rate.

Choice C reason: This is incorrect because sildenafil and nitrates do not increase the risk of bleeding, unless they are combined with other drugs that affect the blood clotting process, such as anticoagulants or antiplatelets.

Choice D reason: This is correct because sildenafil and nitrates can cause a significant decrease in blood pressure when taken together, as they both cause vasodilation and increase nitric oxide levels. This can lead to hypotension, dizziness, fainting, or even a heart attack or stroke. The patient should avoid taking sildenafil and nitrates within 24 hours of each other.