Question

The prescription for a 4-month-old is penicillin G 150,000 units intramuscularly bid. The drug is supplied as a unit dose of 600,000 units in a 5-mL vial. The nurse should give the dose as _____ mL.

a) 1.25 mL
b) 2.5 mL
c) 3.75 mL
d) 5 mL

Answer 1

The correct answer is: a) 1.25 mL
To provide the prescribed 150,000 units of penicillin G, the nurse should administer 1.25 mL from the vial containing 600,000 units in 5 mL solution.

Step-by-step explanation:

The prescription is for penicillin G 150,000 units intramuscularly bid (twice a day), and it is supplied as a unit dose of 600,000 units in a 5-mL vial. To determine how many milliliters should be given for a single dose of 150,000 units, one can set up a proportion since the relationship between units of penicillin and milliliters of solution is linear. By comparing the prescribed units to the supplied units and aligning this with the milliliters of solution, we establish the proportion:

Prescribed units : Supplied units = X mL : Total mL in vial

150,000 units : 600,000 units = X mL : 5 mL

By cross-multiplying and solving for X, we find that X, the volume to administer, is 1.25 mL. Therefore, the nurse should give the dose as 1.25 mL, which represents the correct amount of penicillin G for the prescribed dosage of 150,000 units.

The correct answer is: a) 1.25 mL