Question

10. Order states to administer cefazolin 250 mg IM. Available is cefazolin 1 gram vial.

The directions state to add 3 mL of NS to obtain a concentration of 1 gram per
4mL. How many mL will the nurse administer?

Answer 1

To administer 250 mg of cefazolin, we need to calculate the appropriate volume of the 1-gram vial to use.

First, we need to calculate the concentration of the solution after adding 3 ml of NS to the 1-gram vial:

1 gram cefazolin + 3 ml NS = 4 ml solution

1 gram cefazolin / 4 ml solution = 0.25 grams cefazolin per ml

Next, we can use dimensional analysis to calculate the volume of solution needed to provide 250 mg of cefazolin:

0.25 g cefazolin / 1 ml solution = 250 mg cefazolin / x ml solution

x = (250 mg cefazolin * 1 ml solution) / 0.25 g cefazolin

x = 1 ml solution

Therefore, the nurse will administer 1 ml of the cefazolin solution.

Explanation: