A nurse plans to give an infant a dose of amoxicillin that is measured at 320 mg. What is the correct volume to administer if the suspension is 400 mg/5 mL?

To determine the correct volume to administer for a dose of 320 mg of amoxicillin when the concentration of the suspension is 400 mg per 5 mL, you can use a ratio and proportion method.

First, convert the concentration into a simpler form. The suspension contains 400 mg in 5 mL, which can be expressed as 80 mg per 1 mL (since 400 mg divided by 5 mL equals 80 mg/mL).

Next, to find out how many milliliters are needed to provide a 320 mg dose, divide the desired dose (320 mg) by the concentration (80 mg/mL):

320 mg ÷ 80 mg/mL = 4 mL.

This calculation indicates that 4 mL of the amoxicillin suspension will deliver the required dose of 320 mg. Therefore, the correct volume to administer is indeed 4 mL, aligning with the provided answer.