If a doctor prescribes 0.5 mg of a medication and it is available at 0.25 mg/mL, how much medication do you need to draw?

To determine how much of the medication to draw, we need to understand the relationship between the prescribed dosage and the concentration of the medication available.

The prescribed dose is 0.5 mg, and the concentration of the medication available is 0.25 mg/mL. To find out how many milliliters are needed to obtain the 0.5 mg dose, the following calculation can be done:

1. Start with the dosage to be administered: 0.5 mg.
2. Next, recognize the concentration: 0.25 mg/mL.

Now, divide the total amount of medication required (0.5 mg) by the concentration (0.25 mg/mL):

0.5 mg ÷ 0.25 mg/mL = 2.0 mL.

This tells us that to get 0.5 mg of the medication from a solution that provides 0.25 mg in each milliliter, you need to draw 2.0 mL. Therefore, the correct answer is 2.0 mL.

This option is the correct choice because it accurately reflects the volume required to deliver the prescribed medication based on its available concentration.