If a physician prescribes 2.5 mg of morphine for a client, how many mL should the nurse draw from a vial labeled 4 mg/mL?

To determine how many mL of morphine the nurse should draw from a vial that contains 4 mg/mL, the calculation involves understanding the concentration of the solution and the amount prescribed.

The physician prescribed 2.5 mg of morphine. The vial contains morphine at a concentration of 4 mg per 1 mL. To find out how many mL is needed for 2.5 mg, you can set up a proportion or use a simple formula:

Since the vial has 4 mg per 1 mL, you can calculate the volume by dividing the prescribed dose by the concentration:

Volume (mL) = prescribed dose (mg) / concentration (mg/mL)

Plugging in the values:

Volume (mL) = 2.5 mg / (4 mg/mL) = 0.625 mL

This calculation shows that to obtain 2.5 mg of morphine from a solution that contains 4 mg/mL, the nurse needs to draw 0.625 mL. This aligns with the correct answer. Understanding the relationship between dosage and concentration is crucial for safe medication administration.