For a prescription of Compazine at 10 mg, how many milliliters should be ordered from a vial containing 5 mg/mL?

To determine the correct volume to administer for a prescription of Compazine at 10 mg when the vial concentration is 5 mg/mL, you need to calculate how many milliliters contain the required dosage of 10 mg.

First, understand the concentration of the medication: the vial provides 5 mg of Compazine in each milliliter. To find out how many milliliters are needed to achieve the total of 10 mg, you can use the formula:

[ \text{Volume (mL)} = \frac{\text{Desired Dose (mg)}}{\text{Concentration (mg/mL)}} ]

Substituting in the known values:

[ \text{Volume (mL)} = \frac{10 , \text{mg}}{5 , \text{mg/mL}} = 2 , \text{mL} ]

This calculation shows that to obtain a total of 10 mg, 2 mL of the solution must be administered. Therefore, the correct option indicates that the prescription should order 2 mL from the vial. This approach reflects proper calculations in pharmacology related to dosing and volume conversions, critical skills for ensuring accurate medication administration.